An evaluation of sedimentary molybdenum and iron as proxies for …myweb.fsu.edu/jdowens/Publications/Hardisty_2018.pdf · 2018. 7. 26. · Key words: paleoredox, iron speciation,

AN EVALUATION OF SEDIMENTARY MOLYBDENUM AND IRON ASPROXIES FOR PORE FLUID PALEOREDOX CONDITIONS

DALTON S HARDISTYdagger TIMOTHY W LYONSNATASCHA RIEDINGER TERRY T ISSONsect JEREMY D OWENSsectsect

ROBERT C ALLERsectsectsect DANNY M RYEsect NOAH J PLANAVSKYsectCHRISTOPHER T REINHARDsectsectsectsect BEN C GILLDagger ANDREW L MASTERSONDaggerDagger

DAN ASAELsect and DAVID T JOHNSTONDaggerDaggerDagger

ABSTRACT Iron speciation and trace metal proxies are commonly applied togetherin efforts to identify anoxic settings marked by the presence of free sulfide (euxinia)or dissolved iron (ferruginous) in the water column Here we use a literaturecompilation from modern localities to provide a new empirical evaluation of coupledFe speciation and Mo concentrations as a proxy for pore water sulfide accumulation atnon-euxinic localities We also present new Fe speciation Mo concentration and Sisotope data from the Friends of Anoxic Mud (FOAM) site in Long Island Soundwhich is marked by pore water sulfide accumulation of up to 3 mM beneath oxygen-containing bottom waters For the operationally defined Fe speciation scheme lsquohighlyreactiversquo Fe (FeHR) is the sum of pyritized Fe (Fepy) and Fe dominantly present in oxidephases that is available to react with pore water sulfide to form pyrite Observationsfrom FOAM and elsewhere confirm that FepyFeHR from non-euxinic sites is agenerally reliable indicator of pore fluid redox particularly the presence of pore watersulfide Molybdenum (Mo) concentration data for anoxic continental margin sedi-ments underlying oxic waters but with sulfidic pore fluids typically show authigenic Moenrichments (2ndash25 ppm) that are elevated relative to the upper crust (1ndash2 ppm)However compilations of Mo concentrations comparing sediments with and withoutsulfidic pore fluids underlying oxic and low oxygen (non-euxinic) water columnsexpose non-unique ranges for each exposing false positives and false negatives Falsepositives are most frequently found in sediments from low oxygen water columns (forexample Peru Margin) where Mo concentration ranges can also overlap with valuescommonly found in modern euxinic settings FOAM represents an example of a falsenegative where despite elevated pore water sulfide concentrations and evidence foractive Fe and Mn redox cycling in FOAM sediments sedimentary Mo concentrationsshow a homogenous vertical profile across 50 cm depth at 1 to 2 ppm A diageneticmodel for Mo provides evidence that muted authigenic enrichments are derived fromelevated sedimentation rates Consideration of a range of additional parameters mostprominently pore water Mo concentration can replicate the ranges of most sedimen-tary Mo concentrations observed in modern non-euxinic settings Together themodern Mo and Fe data compilations and diagenetic model provide a framework for

Department of Earth and Environmental Sciences Michigan State University East Lansing Michigan48824 USA

Department of Geology and Geophysics Woods Hole Oceanographic Institution Woods HoleMassachusetts 02543 USA

Department of Earth Sciences University of California-Riverside Riverside California 92521 USA Boone Pickens School of Geology Oklahoma State University Stillwater Oklahoma 74075 USAsect Department of Geology and Geophysics Yale University New Haven Connecticut 06511 USAsectsect Department of Earth Ocean and Atmospheric Science National High Magnetic Field Laboratory

Florida State University Tallahassee Florida 32310 USAsectsectsect School of Marine and Atmospheric Sciences Stony Brook University Stony Brook New York 11794

USAsectsectsectsect School of Earth and Atmospheric Sciences Georgia Institute of Technology Atlanta Georgia

30318 USADagger Department of Geosciences Virginia Polytechnic and State University Blacksburg Virginia 24061

USADaggerDagger Department of Earth and Planetary Sciences Northwestern University Evanston Illinois 60208 USADaggerDaggerDagger Department of Earth and Planetary Sciences Harvard University Cambridge Massachusetts 02138

USAdagger Corresponding author dhardistywhoiedu

[American Journal of Science Vol 318 May 2018 P 527ndash556 DOI 10247505201804]

527

identifying paleo-pore water sulfide accumulation in ancient settings and linkedprocesses regulating seawater Mo and sulfate concentrations and delivery to sedi-ments Among other utilities identifying ancient accumulation of sulfide in porewaters particularly beneath oxic bottom waters constrains the likelihood that thosesettings could have hosted organisms and ecosystems with thiotrophy at their founda-tions

Key words paleoredox iron speciation molybdenum pore water sulfide LongIsland Sound

introduction

Iron speciation and molybdenum concentrations have been well calibrated inmodern settings for recognizing end-member euxinic (anoxic and H2S-containing)and ferruginous (anoxic and iron-rich) settings in the geologic record (Berner 1970Raiswell and others 1988 Canfield and others 1992 Canfield and others 1996Raiswell and Canfield 1998 Poulton and Canfield 2005 2011 Lyons and Severmann2006 Algeo and Lyons 2006 Raiswell and others 2018) This past research hasresulted in extensive application of these proxies toward an improved understandingof water column redox evolution and dynamics through time including Phanerozoicocean anoxic events (Maumlrz and others 2008 Gill and others 2011) the Proterozoic(Poulton and others 2004 Canfield and others 2007 Scott and others 2008 Li andothers 2010 Planavsky and others 2011 Johnston and others 2012 Sperling andothers 2015) and the Archean (Reinhard and others 2009 Kendall and others 2010Scott and others 2011) Beyond the recognition of ancient euxinic and ferruginouswater columns more recent research has provided a context for using Fe and Moproxies to infer accumulation of sulfidic pore waters in ancient sediments includingthose deposited beneath water columns lacking dissolved sulfide and Fe (Scott andLyons 2012 Sperling and others 2015) Refined recognition of these conditions hasimportant implications for the evolution of the marine sulfate reservoir and forinterpretation of the geochemical impacts of sediment mixing induced by benthicinfaunal communities through time (Canfield and Farquhar 2009 Tarhan and others2015) Additionally pore water sulfide has implications for bottom water habitabilityand the evolution of thiotrophy and associated symbiotic relationships among com-bined micro-macrofaunal communities (Sperling and others 2015 Tarhan andothers 2015) However although a broad framework currently exists for understand-ing the conditions leading to Mo and Fe fixation in sulfidic sediments (see back-ground) few studies have systematically evaluated proxy expressions from modernsediments to assess their potential as uniquely pore fluid indicators of paleoredox inancient sediments

Here we specifically assess the paleoredox proxy potential of Fe speciation andMo concentrations to recognize the presence or absence of pore water sulfideaccumulation during early diagenesis from modern marine sediments underlyingwater columns without stable euxinia and a range of ambient oxygen concentrationsThis endeavor is grounded in a broad context provided by compilations of Fespeciation and Mo concentrations from modern localities where water column andpore water redox conditions are well characterized In addition we present an originalcase study with Fe-speciation Mo concentration and S concentration and isotope datafor sediments from the oxic FOAM (Friends of Anoxic Mud) site in Long Island Sound(LIS) USA where sedimentary pore fluids are well-known to host elevated andpersistent pore water sulfide concentrations Previous studies of LIS including theFOAM site have been fundamental to the initial development of the Fe paleoredoxproxies and a range of other sedimentary geochemical signatures (Aller and Cochran1976 Goldhaber and others 1977 Benninger and others 1979 Benoit and others

528 D Hardisty and othersmdashAn evaluation of sedimentary molybdenum

1979 Aller 1980a 1980b Krishnaswami and others 1980 Westrich ms 1983 Bernerand Westrich 1985 Canfield 1989 Canfield and Berner 1987 Canfield and others1992 Canfield and Thamdrup 1994 Raiswell and others 1994 Raiswell and Canfield1998) We use a diagenetic model for Mo to provide constraints on the environmentalfactors that best explain the observed modern sediment concentration ranges andprovide a context for interpreting non-euxinia related drivers of changes in Moconcentrations from ancient sediments

background and proxy framework

The Iron ProxiesThe utility of the Fe geochemical proxies is built on a foundation of extensive

work on the reactivity of Fe minerals with dissolved sulfide in sedimentary environ-ments (Berner 1970 Raiswell and others 1988 Canfield and others 1992 Raiswelland others 1994 Canfield and others 1996 Raiswell and Canfield 1998 Poulton andCanfield 2005) and a well-developed understanding of syngenetic (water column)versus diagenetic pyrite formation (Canfield and others 1996 Lyons 1997 Wijsmanand others 2001 Lyons and others 2003 Anderson and Raiswell 2004 Raiswell andAnderson 2005) The refined sequential extraction scheme of Poulton and Canfield(2005) is designed to target Fe phases emphasizing carbonate-bound Fe oxide Fe(dithionite extractable Fedith) and magnetite Fe (oxalate extractable Femag) whichall react with sulfide to form pyrite (Fepy) and Fe monosulfides (acid volatile sulfurFeAVS) on time scales relevant to early diagenesis (Canfield 1989 Canfield and others1992 Canfield and others 1996) These iron phases when summed with pyritecomprise the operationally defined lsquohighly reactiversquo Fe (FeHR) pool

Inputs of detrital FeHR into sediments permit the production of pyrite whenexposed to sulfide but typical lithogenic ratios of FeHRFeT 038 and FeTAl massratios 05 are maintained when anoxic (euxinic or ferruginous) conditions are notpresent in the water column (Raiswell and Canfield 1998 Lyons and others 2003Lyons and Severmann 2006) In contrast if anoxia develops and persists in the watercolumn both FeHRFeT and FeTAl are elevated beyond these crustal baselines andthose enrichments are often used to infer ancient anoxia According to one modelsoluble Fe(II) generated during reductive dissolution of Fe-oxides along continentalmargins diffuses out of sediments allowing enhanced delivery of FeHR through an lsquoFeshuttlersquo to the deep basin where it is captured as syngenetic pyrite (Canfield andothers 1996 Lyons 1997 Raiswell and Canfield 1998 Wijsman and others 2001Anderson and Raiswell 2004 Raiswell and Anderson 2005 Lyons and Severmann2006 Severmann and others 2008 Severmann and others 2010 Scholz and others2014b) This lsquoextrarsquo Fe is decoupled from the local delivery of silicate phases includingunreactive Fe fractions with the net result of FeHRFeT 038 (Raiswell and Canfield1998) and FeTAl 05 Under euxinic conditions near complete reaction of the FeHRto form pyrite leads to FepyFeHR ratios in excess of 07 to 08 (Poulton and others2004 Maumlrz and others 2008 Poulton and Canfield 2011)

In sulfidic sediments underlying non-euxinic or ferruginous water column condi-tions hence FeHRFeT038 and FeTAl 05 the FepyFeHR ratio is anticipated tobe 07 This prediction is based on work from the Long Island Sound FOAM site (seeFOAM background) where it was initially shown that pore water sulfide accumulationis preceded by the consumption of lsquohighly reactiversquo Fe minerals via reaction withsulfide to form pyrite (Canfield 1989 Canfield and others 1992) Sequential Feextractions and associated FepyFeHR of ancient shales have been applied previously tointerpret pore water redox in ancient sediments (Sperling and others 2015) but nostudy has evaluated the potential of FepyFeHR from modern non-euxinic settings touniquely indicate pore water sulfide accumulationmdashhence this study

529and iron as proxies for pore fluid paleoredox conditions

Molybdenum GeochemistryMolybdenum is the most abundant transition metal in the modern ocean with a

near uniform concentration of 104 nM (Broecker and Peng 1982 Emerson andHuested 1991) and a relatively long residence time of 450 kyr (Miller and others2011) Molybdenum exists almost entirely as molybdate (MoO4

2) under oxic condi-tions delivered primarily from oxidative weathering of sulfide minerals (Miller andothers 2011) Molybdate has a strong affinity for sorption to Mn and Fe oxides whichis a significant pathway of Mo deposition in the modern dominantly oxic ocean(Shimmield and Price 1986 Barling and Anbar 2004) In the absence of free sulfidein the water column and sediments Mo buried with oxides will often diffuse back tothe overlying water column following reductive dissolution of the oxides duringsediment diagenesis (Shimmield and Price 1986 Goldberg and others 2012 Scottand Lyons 2012) with the possibility of little to no authigenic sediment enrichmentand thus concentrations near those characteristic of average continental crust (1ndash2ppm)

Under sulfide-rich conditions however Mo is readily converted from MoO42 to

particle reactive thiomolybdate (MoO4-xSx2 (Helz and others 1996 Erickson and

Helz 2000 Zheng and others 2000) which is buried in association with organicmatter and pyrite (Algeo and Lyons 2006 Chappaz and others 2014 Dahl and others2017 Wagner and others 2017) This relationship has particular importance whenconsidering settings with sulfide restricted to the sediment pore fluids versus euxinicsites In either case if total dissolved sulfide concentrations exceed 100 M (withsome sensitivity to ambient pH) quantitative sulfidization of MoO4

2 to MoS42 is

expected (Helz and others 1996 Erickson and Helz 2000 Zheng and others 2000Helz and others 2011) Molybdenum enrichments under euxinic water columnconditions typically exceed the average continental crust value of approximately 1 to 2ppm (Taylor and McLennan 1995) by a significant marginmdashwith sediment concentra-tions of up to hundreds of ppm (Scott and Lyons 2012) and distinct relationships withthe abundance of organic carbon in the sediments (Algeo and Lyons 2006) Inmodern sulfidic sediments accumulating beneath an oxic water column Mo deliveredto the sedimentsmdashincluding that associated with oxide deposition and subsequentdissolutionmdashis retained upon oxide dissolution via reaction with dissolved sulfideamong other possibilities (Scholz and others 2017) Rather than diffusing back to theoverlying water column this Mo is sequestered with organic matter andor pyrite inthe subsurface layers (Helz and others 1996 Erickson and Helz 2000 Helz andothers 2011 Chappaz and others 2014 Dahl and others 2017 Wagner and others2017) A recent survey of Mo concentrations from non-euxinic settings with sulfidicpore fluids suggests that authigenic enrichments rarely exceed 25 ppm with most ofthese settings having enrichments below 10 ppm (Scott and Lyons 2012) A newdiagenetic model the new FOAM data and the literature data compilation presentedhere is intended to extend the proxy potential of Mo concentrations to differentiatesettings with pore fluid sulfide accumulation from those lacking sulfide or with sulfidealso present in the water column

FOAMmdashThe Historical ContextPast studies of FOAM and several nearby locations in Long Island Sound must get

credit for giving rise to the Fe-based paleoredox proxiesmdashspecifically degree ofpyritization (DOP) FeHRFeT and FepyFeHR The water column is oxygenated ateach of these localities (Lee and Lwiza 2005 Lee and Lwiza 2008 Wallace and others2014) and sedimentary sulfide concentrations range from 2 to 6 mM at FOAM and theadjacent study sites characterized by high rates of sulfate reduction (Goldhaber andothers 1977 Westrich ms 1983 Canfield 1989 Canfield and others 1992) Studies at


FOAM demonstrate that DOP data from sediments with sulfidic pore waters butunderlying oxic water columns are clearly distinguishable from those of euxinic watercolumn settings Specifically DOP values from FOAM and nearby LIS sediments donot exceed 04 (Berner 1970 Canfield and others 1992 Raiswell and Canfield1998) which are readily distinguished from the values of 07 found in sedimentsunderlying euxinic water columns (Raiswell and others 1988) Similarly comparisonsof FeHRFeT data from FOAM and other modern oxic localities to sediments inmodern euxinic basins established the FeHRFeT threshold of 038 now used widelyto identify ancient euxinic and ferruginous water columns (Raiswell and Canfield1998) These same studies also demonstrated the reactivity of common Fe mineralsmdashferrihydrite lepidocrocite goethite hematite magnetitemdashtowards sulfide to formpyrite Concurrently other Fe minerals (for example sheet silicates) were foundinstead to react with sulfide on much longer timescales well beyond those of earlydiagenesis (Canfield and Berner 1987 Canfield 1989 Canfield and others 1992Raiswell and others 1994)

The intermediate DOP values at FOAM despite high and persistent levels of porewater sulfide set the stage of a deeper exploration of reactive iron (reviewed in Lyonsand Severmann 2006) and the mechanistic underpinnings of the Fe-based paleoredoxproxiesmdashleading ultimately to the now widely used sequential extraction protocol(Poulton and Canfield 2005) This refined approach targets the lsquohighly reactiversquo Fephases described above Collectively data from FOAM and the modern Black Sea(Canfield and others 1996) exposed the need for lsquoextrarsquo highly reactive Fe in euxinicsettings to explain observations of elevated DOP and FeHRFeT (Canfield and others1996 Lyons 1997 Raiswell and Canfield 1998 Wijsman and others 2001 Andersonand Raiswell 2004 Raiswell and Anderson 2005 Lyons and Severmann 2006Severmann and others 2008 Severmann and others 2010 Scholz and others 2014b)Our study however is the first report of FeHRFeT data from FOAM using theexpanded suite of Fe extractions (Poulton and Canfield 2005) and to specificallyreport FepyFeHR for this location Comparisons with previous studies are possiblehowever since data for Fedith Fepy and FeAVS were already available for the upper 12cm of FOAM (Berner and Canfield 1989 Raiswell and Canfield 1998) Those studiesyielded FeHRFeT ratios of 02 to 03 and FepyFeHR values approaching 08 in thepresence of high concentrations of pore water sulfide

Beyond Fe proxy development and calibration the FOAM site has been the focusof numerous now classic studies on sulfate reduction and sulfur disproportionation(Goldhaber and others 1977 Westrich ms 1983 Canfield and Thamdrup 1994)bioturbation (Aller 1980a 1980b Berner and Westrich 1985) and sedimentationrates (Krishnaswami and others 1984) among other topics (Aller and Cochran 1976Benninger and others 1979 Benoit and others 1979 Krishnaswami and others 1980)

Sedimentation rates at FOAM and adjacent study sites have been found to rangefrom 003 to 03 cmyr (Goldhaber and others 1977 Krishnaswami and others 1984)The presence of bioturbation and infaunal irrigation to depths of 8 to 10 cm(Goldhaber and others 1977) has left the upper 4 cm of the sediment well mixed(Aller 1980a Krishnaswami and others 1984) The activities of these burrowingorganisms have been documented to change on seasonal time scales (Goldhaber andothers 1977 Aller 1980a 1980b) thus enhancing infaunal irrigation of sulfate to thesediments in the summer compared to winter and creating distinct differences in thedepth of sulfide accumulation from winter to summer Bioturbation is the dominanttransport mechanism in the summer and diffusion dominates during the winter(Goldhaber and others 1977) Previous FOAM studies have suggested that diageneticprocesses are not in steady state in the upper 10 cm where active bioturbation andmaximum seasonal temperature variation occur and are approximately at steady state


at depth (Aller 1980a 1980b Westrich ms 1983 Boudreau and Canfield 1988)Occasional dredging of portions of the Sound may cause sediment reworking but nodirect impacts of dredging have been observed at FOAM

methodsOur FOAM core was collected in October 2010 using a modified piston-gravity

corer (fig 1) The site is located at 41deg14rsquo2682rsquorsquoN 72deg44rsquo4478rsquorsquoW at a water depth ofapproximately 10 m Cores were sectioned into 1 to 2 cm intervals within 2 hours ofcollection and the sediment was transferred into 50 mL centrifuge tubes Pore waterswere extracted within an N2-flushed glove bag using rhizons within several hours ofcore retrieval (SeebergElverfeldt and others 2005) Pore water subsamples forhydrogen sulfide (H2S) were fixed with zinc acetate while subsamples for metalanalysis were acidified with trace metal grade HCl Residual sediment samples weresealed and frozen immediately minimizing oxidation

Pore water H2S concentrations were measured using the methylene blue method(Cline 1969) Sulfate concentrations were determined by suppressed ion chromatog-raphy with conductivity detection (ICS-2000 AS11 column Dionex) at the StableIsotope Geobiology Laboratory at Harvard University Pore water concentrations ofMn Fe and Mo were measured via inductively coupled plasma-mass spectrometry(ICP-MS Agilent 7500ce) at the University of California Riverside Sample replicatesyielded standard deviations 5 percent for Mn Fe and Mo

Acid volatile sulfur (AVS) and chromium reducible sulfur (CRS) were determinedsequentially using freshly thawed frozen samples and quantified by iodometric titra-tion (Canfield and others 1986) Recoveries of sulfur for pure pyrite standardsaveraged 86 92 percent of the expected amount (n 8) however duplicateanalyses of FOAM samples revealed better reproducibility To determine the degree ofpyritization (DOP) for FOAM sediments Fe was extracted using the boiling HClmethod of Berner (1970) and Raiswell and others (1988) Following from previouswork (Berner 1970 Raiswell and others 1988) DOP was calculated as Fepy(Fepy FeHCl)

Samples with the bulk of pore water previously extracted but still wet were thawedand weighed for determination of Fe speciation using a modified version of the

Fig 1 Map showing FOAM location Image is taken from Google Earth


sequential Fe extraction of Poulton and Canfield (2005) An ascorbate step targetingferrihydrite (Ferdelman ms 1988 Kostka and Luther 1994 Raiswell and others2010) or Feasc was added and replaced a sodium acetate extraction that targetscarbonate-bound Fe given the unlikelihood of Fe carbonate precipitation in thesesulfide-rich sediments To minimize oxidation of Fe sulfide phases during the extrac-tion procedures the solutions were bubbled with N2 gas prior to extraction and theheadspace extraction vials were filled with N2 gas and sealed throughout the extrac-tions Replicate samples yielded precisions of 7 percent for Feasc Fedith and FemagAll iron phase values are reported on dry sediment basis corrected for water contentsCombined Fepy FeAVS Feasc Fedith and Femag represent the total lsquohighly reactiversquo Fepool (FeHR)

FOAM sediment samples were dried and then homogenized via mortar and pestleafter removal of visible shell material Total carbon was measured using an Eltra CS-500carbon-sulfur analyzer Total inorganic carbon was determined by measuring CO2liberated after addition of 25 N HCl Total organic carbon (TOC) was determined asthe difference between total carbon and total inorganic carbon

Bulk concentrations of Fe Mn Al and Mo were determined using a totaldigestion of ashed samples (450 degC) in trace metal grade HFHNO3HCl Contents ofFe Mn Al and Mo were measured using an Agilent 7500ce ICP-MS at the University ofCalifornia-Riverside Repeated analyses of USGS reference material SDO-1 were in-cluded to assess accuracy and precision with all elements analyzed in this study fallingwithin the reported ranges The SDO-1 standard contains elevated concentrations ofeach of the elements of interest relative to FOAM samples and was therefore dilutedduring ICP-MS analysis to mimic the concentration range observed at FOAM Diges-tion and analysis of duplicate and triplicate FOAM sediment samples revealed standarddeviations (1) of 01 weight percent for Al Mn and Fe and 02 ppm for Mo

For the sake of comparison to past studies we also include previously unpublishedS isotope data from FOAM The FOAM-1 core was collected in August 1974 andsectioned in 1 to 2 cm intervals under N2 in a glove bag within 12 hours of collectionPore waters were extracted by squeezing and filtered (Kalil and Goldhaber 1973)Additional details can be found in Aller (1980a 1980b)

To determine the isotopic composition of pore water sulfate in FOAM-1 porewater samples were diluted with 70 mL distilled water acidified with HCl andheated BaSO4 was precipitated following addition of BaCl2 (10 wv) The acidvolatile sulfur was extracted immediately following sample collection by reaction withcold 12 N HCl and the resulting H2S was stripped with N2 and precipitated as Ag2S in aAgNO3 trap (Aller 1980a 1980b) BaSO4 and Ag2S were combusted to SO2 (Ag2S bythe cupric oxide method) and the sulfur isotope compositions were measured via aNuclide 6ndash60 isotope ratio mass spectrometer at Yale University For both SO4

2 andAVS the sulfur isotope data are presented in conventional delta notation (34S) inpermil (permil) relative to the Vienna Canyon Diablo Troilite (VCDT) standard andequation 1 below which also applies to 33S Park City pyrite a synthetic ZnS anda synthetic PbS were used as secondary standards Standard deviations (1) for theanalyses of secondary standards and duplicate samples were less than 01 permil

3XS [(3XS32S)sample(3XS32S)standard 1] 13 1000 (1)

For the 2010 FOAM core sulfur isotope analyses were performed at the StableIsotope Geobiology Laboratory at Harvard University Minor isotopes were measuredvia fluorination of Ag2S as shown below in equation 2 For sulfate the samples are firstreduced to Ag2S with a mixture of hydriodic acid (HI) hypophosphorous acid(H3PO4) and hydrochloric acid (HCl) at 90 degC for 3 hours (Forrest and Newman1977 Johnston and others 2007) Powdered Ag2S samples were fluorinated at 300 degC


in an F2 atmosphere at 1013 stoichiometric excess Product SF6 was cryogenically andchromatographically purified and analyzed on a ThermoFinnigan 253 in Dual Inletmode Repeated analyses of standards IAEA-S1 S2 S3 yielded a reproducibility of 02permil and 0006 permil for 34S and 33S respectively Samples are reported versusVCDT which is calibrated from the long-term running average of IAEA-S1 versus theworking standard gas at Harvard University

33S 33S [(34S1000 1)0515 1] 13 1000 (2)

resultsWe compiled literature data (figs 2 and 3) that includes new data and earlier

results from FOAM Fe speciation from diverse modern settings (n 1068) and Moconcentrations from modern non-euxinic settings (n 1421) All citations are given inthe respective figure captions For both Fe speciation and Mo concentrations lsquooxicrsquo isdefined as settings with 15 M O2 and low oxygen conditions are defined as having15 M O2 but without persistent sulfide accumulation in the water column For Modata from the Namibian Shelf are included in the low oxygen settings In some casesthese low oxygen settings such as the Peru Margin are reported to have transientwater column sulfide plumes (Scholz and others 2016) We distinguish between dataassociated with dissolved hydrogen sulfide in the pore waters and pore waters witheither dissolved sulfide below detection or appreciable dissolved Fe which impliesnegligible sulfide When available the compiled FepyFeHR data include iron associ-ated with acid-volatile sulfide (AVS or lsquoFeSrsquo the iron monosulfide precursors to pyriteformation) In figure 3 intervals with Mo associated with surface Mn enrichments (2wt Mn in most cases) are not included

Our pore water sulfide concentrations at FOAM are near 3 mM which are withinthe range of concentrations previously observed (6 mM Goldhaber and others1977 Canfield and others 1992) with measureable sulfide accumulation limited todepths of approximately 8 cm and greater (fig 4A) Consistent with the down coreincrease in sulfide pore water sulfate concentrations decrease with depth (fig 4A)The TOC content ranges from 05 to 20 weight percent (fig 4B) Pyrite is observedat all depths (fig 4C) and is consistent with previously reported ranges at FOAM(Canfield 1989 Canfield and others 1992 Raiswell and Canfield 1998) AVS wasnot detected in this study Because some AVS has been reported from past FOAMstudies (Aller 1980b Canfield 1989 Canfield and others 1992 Raiswell andCanfield 1998) it may be missing in our samples due to oxidation Sulfur isotopedata (32S 33S and 34S) for pyrite acid volatile sulfide and sulfate are shown forboth the FOAM-1 (1974) and FOAM 2010 cores (fig 4D) and are remarkablysimilar despite collection separated by nearly 40 years For the minor sulfurisotopes (fig 4E) the data mimic previous observations from similar sites (John-ston and others 2008) with sulfate showing increasing 33S in parallel with 34Sincreases Sulfide 33S compositions are also enriched (averaging 016permil) Sulfurisotope data are show in tables 1 and 2

Results for individual Fe fractions are shown in table 3 and figure 5 Dissolved porewater Fe concentrations peak in the upper 4 cm rising from 424 M at 05 cm to 629M at 2 cm before decreasing to 094 M at 10 cm (fig 5A) These dissolved Fe valuesare notably similar to autumn cores from previous studies at FOAM (Aller 1980b)Dithionite Fe is the most abundant measured highly reactive Fe fraction in the upper10 cm other than pyrite peaking at 014 weight percent (fig 5B) while other Fefractions are negligible (table 3) Calculated values for DOP are mostly near 04FeTAl ratios are approximately 05 and FeHRFeT remains 038 (figs 5C and 5D)Ratios of FepyFeHR ratios decline in the upper 5 cm of the core from 086 to 055 andare persistently 08 starting at 8 cm (fig 5D) Our values for FeTAl FeHRFeT


Fig

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mea

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ated

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olve

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s


Fig

4FO

AM

con

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trat

ion

profi

les

for

(A)

pore

wat

ersu

lfat

ean

dh

ydro

gen

sulfi

de(

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tota

lor

gan

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(TO

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(C)

wei

ght

perc

ent

sulf

urin

pyri

te

Als

oin

clud

edar

eis

otop

eco

mpo

siti

ons

of(D

)34S

(34S)

ofsu

lfat

ean

ddi

ssol

ved

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dean

d(E

)33S

(33S)

for

sulf

ate

and

diss

olve

dsu

lfide

In

part

Dd

ata

are

show

nfr

ombo

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(201

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show

nin

tabl

es1

and

2


FepyFeHR and DOP are all similar to those reported or calculated from datapublished in previous FOAM studies (Krishnaswami and others 1984 Canfield 1989Canfield and others 1992 Raiswell and Canfield 1998)

TABLE 1

Sulfur isotope values for pore water sulfate and AVS for samples from FOAM

Core Depth (cm) δ34S sulfate (permil) δ34S AVS (permil) δ34S pyrite (permil)FOAM-1 0 205FOAM-1 05 234 -201FOAM-1 15 251 -184FOAM-1 25 247 -211 -230FOAM-1 35 262 -203 -232FOAM-1 45 258 -199 -234FOAM-1 55 268 -207 -229FOAM-1 65 282 -227FOAM-1 75 286 -231FOAM-1 105 309FOAM-1 115 309FOAM-1 125 32 -232FOAM-1 135 333 -221FOAM-1 145 -218FOAM-1 145 -217FOAM-1 155 338 -216FOAM-1 165 335 -211FOAM-1 175 343FOAM-1 185 346 -191

The data are presented in figure 4

TABLE 2

Multiple sulfur isotope data from the 2010 FOAM core

sulfate sulfideDepth δ 34S (permil) Δ33S (permil) δ 34S (permil) Δ 33S (permil)0 (bw) 2085 0040

2 2187 00324 2144 00418 2398 003612 3735 0113 -1895 014916 3600 0104 -1948 015520 3797 0122 -1780 015924 4216 0115 -1707 017928 4363 011732 4428 011936 4365 010240 4380 0116



TA

BL

E3

Res

ults

for

Fe

spec

iati

on

degr

eeof

pyri

tiza

tion

(DO

P)

bulk

sedi

men

tary

Fe

and

Al

conc

entr

atio

ns

and

tota

lor

gani

cca

rbon

(TO

C)

Dep

th

(cm

)Fe

asc

(wt

)Fe

dith

(wt

)Fe

mag

(wt

)Fe

py(w

t )

FeH

Cl(

wt

)

FeT

(wt

)A

l T(w

t )

FeH

RF

e TFe

pyF

e HR

FeTA

lD

OP

TO

C(w

t )

05

002

lt D

L

009

068

137

318

582

025

086

055

033

175

2ltD

L

011

006

065

114

344

661

024

079

052

036

185

40

060

130

050

311

183

166

430

180

550

490

211

206

003

010

006

036

133

296

567

019

065

052

022

122

80

010

040

020

351

053

136

450

140

840

480

251

3110

001

003

002

060

094

272

551

024

091

049

039

101

120

010

020

060

661

022

775

710

270

860

480

392

5014

lt D

L

lt D

L

001

074

116

303

603

025

098

050

039

121

160

010

020

010

650

943

116

190

220

940

500

410

7118

002

003

003

069

100

253

495

031

089

051

041

104

200

050

040

070

711

253

216

040

270

820

530

361

3222

lt D

L

lt D

L

006

093

092

332

667

030

094

050

050

142

240

01lt

DL

0

051

061

243

124

850

360

950

640

461

5226

lt D

L

lt D

L

007

083

112

369

738

024

093

050

043

165

28lt

DL

lt

DL

0

040

931

513

457

010

280

960

490

381

2430

lt D

L

lt D

L

002

086

097

303

569

028

099

053

047

145

320

040

020

080

681

213

176

120

260

830

520

361

4134

003

001

008

059

124

279

589

026

083

047

032

087

36lt

DL

lt

DL

0

030

701

103

196

090

230

960

520

391

5438

lt D

L

001

007

069

120

306

587

025

090

052

036

191

400

030

030

080

661

173

005

730

270

830

520

361

0042

002

001

006

055

114

328

647

019

087

051

033

147

440

020

010

070

711

133

045

700

270

880

530

391

6446

001

lt D

L

009

081

099

331

648

027

089

051

045

149

480

020

010

060

600

773

165

840

220

860

540

441

4250

lt D

L

lt D

L

002

085

084

284

522

031

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054

050

127

DL

D

etec

tion

lim

it

The

data

are

pres

ente

din

figu

re5


Fig

5(A

)D

isso

lved

pore

wat

erFe

con

cen

trat

ion

s(B

)di

thio

nit

eFe

toto

tal

Fera

tios

(Fe d

ithF

e T)

(C)

degr

eeof

pyri

tiza

tion

(DO

P)a

nd

(D)

rati

osof

hig

hly

reac

tive

Feto

tota

lFe

con

cen

trat

ion

s(F

e HRF

e T)

tota

lFe

toA

lrat

ios

(Fe T

Al T

)an

dpy

riti

zed

Feov

erh

igh

lyre

acti

veFe

(Fe p

yFe

HR)

Th

eve

rtic

alba

rre

pres

ents

the

ran

geof

DO

Ppr

evio

usly

mea

sure

dat

FOA

Mfr

omC

anfi

eld

and

oth

ers

(199

2)


Solid-phase Mo concentrations at FOAM do not exceed 2 ppm (figs 6A and 6Btable 4) There is a subsurface pore water Mo maximum of 300 nM at 5 to 7 cm (fig6C) Sedimentary Mn concentrations are in the same range as previous work (Aller1980b) which also show a homogenous distribution in the upper 10 cm (fig 6D) Therange in pore water Mn (fig 6E) is similar to that reported for autumn cores in aprevious FOAM study (Aller 1980b) Pore water Mn accumulation overlies the depthof initial sulfide accumulation and overlaps with pore water Mo concentrationselevated above those of seawater (fig 6)

discussion

Iron Speciation as a Pore Fluid Paleoredox IndicatorIron speciation has been widely used to infer water column paleoredox

conditions but only recently has this application been extended to recognizepaleo-pore water sulfide accumulation (Sperling and others 2015) Applicationstoward recognizing ancient pore water sulfide accumulation are well grounded inwork from modern sites such as FOAM but no previous study has evaluated theability of Fe speciation to uniquely discern pore water sulfide in a diverse range ofmodern localities Pore water sulfide does not accumulate until the most lsquohighlyreactiversquo Fe mineralsmdashfor example ferrihydrite and hematitemdashare quantitativelytitrated in the sediments to form pyrite or other Fe sulfides (Canfield 1989Canfield and others 1992 Raiswell and others 1994) thus elevated FepyFeHR areanticipated for these settings

In line with expectations the Fe speciation data compilation in figure 2 providesbroad evidence that FepyFeHRvalues are 07 in modern sediments where sulfide isindependently constrained to be absent Data from sulfidic pore water systems are lesscommon but with few exceptions (discussed next paragraph) display FepyFeHR ratios07 Examples of sites with sulfidic pore waters include the FOAM site (this studyCanfield 1989) Peru Margin (Boumlning and others 2004 Scholz and others 2011)Santa Barbara Basin (Raven and others 2016) and Argentine Margin (Riedinger andothers 2017) Our FOAM data reveal up to 3 mM of pore water sulfide (fig 4) andFepyFeHR 07 (fig 5) Though the collective data from sites without pore watersulfide have FepyFeHR 07 portions of the FOAM sediment profile without porewater sulfide do have elevated FepyFeHR (fig 5) In the upper 4 cm at FOAM ratios ofFepyFeHR and DOP are elevated compared to the remainder of the upper lsquosulfidefreersquo zone in part because of dissolution of Fe-oxides to produce dissolved Fe in thepore watersmdasha lsquohighly reactiversquo Fe phase not included in these proxy calculationsFactors leading to the presence of pyrite in the lsquosulfide freersquo zone may result fromsediment mixing terriginous input as well as ongoing sulfate reduction (Canfield andothers 1992 Riedinger and others 2017) Regardless the collective data support thatpaleo-pore water sulfide accumulation can be recognized in the geologic record viaFepyFeHR values 07 FeHRFeT ratios of 038 DOP 04 and FeTAl 05(Raiswell and others 1988 Raiswell and Canfield 1998 Lyons and others 2003)although threshold values should be applied with caution

The collective data from sites without stable euxinia suggest that FepyFeHR ratiosof 07 are generally a consistent indicator of pore water sulfide accumulation (fig2A) but lower values lower do not necessarily imply a lack of pore water sulfideExceptions include sediments from the Santa Barbara Basin and the ArgentineMargin where pore water sulfide concentrations approach mM levels yet FepyFeHRratios are 07 The trends in the Argentine Margin are likely a combination of highsedimentation rates and an abundance of magnetite and anomalously high levels ofFe-oxides that react with sulfide to form pyrite (Riedinger and others 2017) As wasshown in a landmark study at the FOAM site dissolved sulfide reacts with lsquoreactiversquo Fe


Fig

6Se

dim

enta

ry(A

)M

oco

nce

ntr

atio

ns

(B)

Mo

Alm

assr

atio

s(C

)po

rew

ater

Mo

con

cen

trat

ion

s(D

)se

dim

enta

ryM

nco

nce

ntr

atio

ns

and

(E)

pore

wat

erM

nco

nce

ntr

atio

ns

Hor

izon

tald

ash

edlin

esre

pres

entt

he

dept

hof

sign

ifica

nts

ulfi

deac

cum

ulat

ion

Sh

aded

area

srep

rese

ntM

oA

lave

rage

shal

eva

lues

from

Tur

ekia

nan

dW

edep

ohl(

1961

)


minerals such as Fe-(oxy)hydroxides and hematite prior to dissolved sulfide accumula-tion but the kinetics of the reaction with magnetite are up to seven orders of magnitudeslower thus allowing for pore water sulfide accumulation despite the presence of lsquohighlyreactiversquo Fe as magnetite (Canfield and others 1992) Sulfur isotope data at FOAM areconsistent with continued pyrite formation from magnetite well below the onset of sulfideaccumulation (Canfield and others 1992) Along the Argentine Margin sporadic andrapid sedimentation maintain non-steady state geochemical conditions and decreasethe residence time of sediments and lsquoreactiversquo Fe minerals including magnetite in athin zone of sulfide accumulation (Riedinger and others 2017) In this zone the rateof sulfate reduction exceeds reaction rates between dissolved sulfide and the abun-dance of various lsquohighly reactiversquo Fe phases (Riedinger and others 2017)

To our knowledge the Fe speciation data compilation in figure 2 is the first toconsider both FeHRFeT and FepyFeHR from the full range of modern settings withavailable data The original work of Raiswell and Canfield (1998) did not considerFepyFeHR but the data compilation presented here generally reinforces their conclu-sions Specifically only sediments from the euxinic Black Sea Cariaco Basin and

TABLE 4

Sedimentary and pore water Mo concentrations

Depth (cm)

Pore water Mo (nM)

Bulk Mo (ppm)

05 1574 11 2 1398 11 4 11 6 2965 10 8 10

10 799 10 12 12 14 1151 10 16 13 18 359 11 20 09 22 30 24 09 26 45 28 10 30 139 10 32 09 34 36 10 38 342 09 40 11 42 144 10 44 10 46 148 11 48 10 50 84 12



Framvaren Fjord record clear indications of euxinia from the collective Fe speciationdata Raiswell and Canfield (1998) made the same observation based on their FeHRFeT compilation Other euxinic sites (for example Orca Basin and Kau Bay) and lowoxygen or lsquonitrogenousrsquo settings with and without intermittent euxinia (for examplePeru Margin) have FeHRFeT 038 and FepyFeHR values that are not consistentlyelevated Other euxinic settings can fall in this group particularly when marked by veryrapid sedimentation such as along the Black Sea margin (Lyons and Kashgarian2005) For the sample set in figure 2 the only low oxygen (in this case seasonallyanoxic) non-euxinic site to yield FeHRFeT ratios of 038 from multiple samples isthe Santa Barbara Basin (Raven and others 2016) where the Fe speciation data are ina range typically interpreted as reflective of ferruginous conditions Redox boundarieseither temporal or spatial have been suggested as necessary for elevated Fe-oxidedelivery relative to detrital values and thus Fe speciation indications of ferruginousconditions (Scholz and others 2014a Scholz and others 2014b Hardisty and others2016) but such settings are seemingly rare in the modern ocean It is possiblehowever that Fe speciation evidence for ferruginous conditions may be more commonthan currently known in sediments from modern low oxygen settings lacking persistentwater column sulfide accumulation To date each of the modern low oxygen oreuxinic localities measured for Fe speciation only include Fepy and Fedith as part of thelsquohighly reactiversquo Fe pool (Raiswell and Canfield 1998 Scholz and others 2014b Ravenand others 2016) Consideration of FeHRFeT and FepyFeHR without Femag and Fecarbspecifically makes ferruginous settings more difficult to identify (Raiswell and others2018)

Lastly some oxic localitiesmdashspecifically nearshore deltaic and fjordic sites charac-terized by rapid sediment reworking and high FeHRFeT in the source sedimentsmdashyield Fe speciation values also consistent with ferruginous conditions (Poulton andRaiswell 2002 Aller and others 2004 Maumlrz and others 2012) Similar trends can befound in FeTAl for some of these localities with mass ratios exceeding the 05typical of sediments underlying oxic waters Such observations stress the necessity toconsider local FeHRFeT and FeTAl detrital baselines the sedimentary context andindependent paleoredox proxies when interpreting Fe geochemistry from ancientsettings (Cole and others 2017 Raiswell and others 2018)

Molybdenum Concentrations as a Pore Fluid Paleoredox IndicatorConcentrations of Mo and Fe speciation are commonly used to infer the presence

of ancient water column sulfide and some recent studies provide evidence that uniqueranges exist for Mo concentrations beneath modern non-euxinic water columnscontaining pore water sulfide (Scott and Lyons 2012) Our compilation of Moconcentrations from oxic settings with and without pore water sulfide support theseapplications and past studies (fig 3) Specifically sedimentary Mo concentrationsabove crustal values but 40 ppmmdashbut mostly 10 ppmmdashand with independentconstraints of oxic water column conditions can generally be attributed to thepresence of pore water sulfide (fig 3A) The authigenic Mo enrichments in oxicsettings with sulfidic pore fluids is largely a function of a Mn or Fe oxide shuttle thatdelivers Mo to the sediments and then fixation with sulfide following reductivedissolution of the oxides (Zheng and others 2000 Scott and Lyons 2012) Indeed therange in Mo concentrations from oxic settings with sulfidic pore fluids is largelyderived from settings with a clear enrichment in Mn and Mo at the surface (omittedfrom compilation in fig 3) and a secondary enrichment in Mo following a decrease inMn concentrations below the zone of sulfide accumulation (Scott and Lyons 2012)For example this relationship is observed from sediment at Loch Etive Scotland(Malcolm 1985) and an estuary in British Columbia (Pedersen 1985) These observa-tions can be clearly contrasted by environments with surficial Mn enrichments that lack


an adjacent subsurface zone of sulfide accumulation such as some hemipelagicsediments (Shimmield and Price 1986) In hemipelagic sediments large Mo enrich-mentsmdashin some cases 100s of ppmmdashcan occur in MnFe-crusts in the upper sedimentzone but decrease to near-detrital values upon Mn and Fe dissolution and thuselevated concentrations are not preserved in the geologic record

Importantly we acknowledge that Mo concentrations from low oxygen settingswith intermittent water column and pore water sulfide have concentrations similar tomany stable euxinic settings and oxic settings with pore water sulfide (fig 3B) This isimportant for the proxy perspective presented here as the current FeHRFeT datafrom low oxygen and intermittently euxinic localities overlap with that of oxic settings(fig 2) indicating a need for further proxies for distinction Additional redox proxieswhich can discriminate low oxygen settings from oxic settings include U concentra-tions (Sundby and others 2004 McManus and others 2006 Algeo and Tribovillard2009 Scholz and others 2011) Mo isotopes (Poulson Brucker and others 2009Hardisty and others 2016 Scholz and others 2017) nitrogen isotopes (Scholz andothers 2017) and iodine contents (Owens and others 2017 Zhou and others 2017)In addition a relationship between TOC and Mo concentrations like that from thePeruvian (Boumlning and others 2004 Scholz and others 2011 Scholz and others 2017)and Namibian (Calvert and Price 1983 Algeo and Lyons 2006) oxygen minimumzones (OMZs) is not observed in oxic settings (Algeo and Lyons 2006)

One possible explanation of the elevated Mo concentrations in these mostlylsquonitrogenousrsquo localities is the intermittent accumulation of low water column hydrogensulfide however thermodynamic considerations and observations from weakly sulfidicplumes (15 M) in the Peru OMZ have been suggested as inconsistent with Moscavenging in these waters (Scholz and others 2016 Scholz and others 2017) Wepoint out that multiple field and theoretical studies indicate a requirement ofsignificant dissolved sulfide accumulation (100 M) prior to authigenic Mo accumu-lation (Helz and others 1996 Erickson and Helz 2000 Zheng and others 2000 Helzand others 2011 Helz and others 2011 Chappaz and others 2014 Dahl and others2017 Wagner and others 2017) In addition a distinct relationship between Mo andTOC like that observed in the Peruvian (Boumlning and others 2004 Scholz and others2011 Scholz and others 2017) and Namibian (Calvert and Price 1983 Algeo andLyons 2006) upwelling zones is otherwise uniquely attributed to settings with at leastintermittent water column sulfide accumulation (Algeo and Lyons 2006) Additionalmechanisms of authigenic Mo enrichments from low oxygen localities include sedimen-tary delivery via oxides during episodic bottom water oxygenation and Mo fixationfollowing reaction with pore water sulfide (Algeo and Tribovillard 2009 Scholz andothers 2011 Scholz and others 2017) In our data compilation Mo concentrationsfrom low oxygen settings with and without pore water sulfide present during samplingare not distinguishable (fig 3C) This observation likely stems from intermittent orpast pore water and water column sulfide accumulation not captured or recognizedduring sampling

Lastly even with elevated pore water sulfide concentrations a number of factorsin oxic localities can lead to a lack of Mo enrichments beyond detrital values This isevident from figure 3 which shows that there is an overlap in the Mo concentrationrange from oxic settings with and without pore water sulfide accumulation In the nextsection we provide a case study from the FOAM site where we observe elevated porewater sulfide but sedimentary Mo concentrations are near detrital values Ultimatelyoxic settings with and without pore water sulfide accumulation can be discerned viaFepyFeHR values (fig 2) However as discussed below the lack of authigenic Moenrichments from sediments with FepyFeHR 08 may provide additional insights toearly diagenetic processes in ancient settings including sedimentation rates and


seasonal oxidative processes A diagenetic model is used to demonstrate the conditionsleading to the range of authigenic Mo enrichments observed in figure 3

FOAM Case Study and Diagenetic ModelPrevious studies have not measured Mo at FOAM but localities with water column

redox and diagenetic regimes similar to FOAM such as an adjacent site in New HavenHarbor and Boston Harbor Massachusetts USA have reported sedimentary Moenrichments up to 8 ppm (Bertine and Turekian 1973 Morford and others 2007)These Mo concentrations are easily distinguished from detrital values (1ndash2 ppm) andare well below Mo concentrations typical of sediments underlying euxinic watercolumns (Scott and Lyons 2012) The up to 3 mM sulfide levels at FOAM are wellabove the 100 M lsquoaction pointrsquo for total dissolved sulfide concentration that favors thetransformation of molybdate to tetrathiomolybdate which can then be efficientlyoften quantitatively scavenged (Helz and others 1996 Zheng and others 2000) Insulfidic sediments following Mn and Fe oxide dissolution near-complete authigenicMo removal from pore waters typically occurs at the transition zone to sulfideaccumulation forming a deeper second solid-phase Mo peak (Scott and Lyons 2012)Sedimentary Mo peaks are not observed at all at FOAM despite pore water Mo levelsgreater than those of the overlying seawater and a clear indication of subsurface Mnand Fe oxide reduction seen in both pore water and sediment data (figs 5 and 6)Below we consider sediment mass balance and a diagenetic model for Mo to determinethe factors that influence authigenic Mo enrichments at FOAM and other non-euxiniclocalities

We use estimates of the lithogenic Mo (Molith) input relative to the observed bulkMo concentrations (Mobulk) to determine the contribution if any from authigenic Mo(Moauth)

Mobulk Molith Moauth (3)

Although constraints on the lithogenic input of Mo to sediments in Long IslandSound are lacking we can estimate this component using a bulk average value ofMoAl for granite- and sandstone-derived lithogenic material of 8ndash18x106 (Turekianand Wedepohl 1961 McLennan 2001 Poulson Brucker and others 2009) Both rocktypes are common regionally near FOAM This lithogenic Mo range also overlaps withbaseline Mo concentrations found in Buzzards Bay and Boston Harbor Massachusetts(Morford and others 2007 Morford and others 2009) which have similar weatheringsource rocks Considering an average sedimentary Al concentration of 60 weightpercent at FOAM (table 3) we calculate a lithologic Mo input of 036 to 14 ppm Thiscontribution is negligible for sediments with large authigenic Mo enrichments butconsidering an average Mo concentration for FOAM sediments of 102 ppm Molith hasthe potential to make up anywhere from 35 to 100 percent of the bulk Mo concentra-tions If authigenic Mo is accumulating at FOAM it is clearly at very low concentra-tions

The total authigenic consumption flux of dissolved Mo within marine sedimentscan be quantitatively estimated using an early diagenetic model (eq 4) The modeltracks solid (organic matter accumulation and authigenic tetrathiomolybdate forma-tion) and dissolved phases (Mo H2S O2) in diffusional exchange with seawater withinthe upper 200 cm of the sediment column

[X]t

D2[X]

z2 [X]

z rxn (4)

Parameters and associated citations are given in table 5 The sum reaction of thetime rate of change of dissolved species in pore waters can be described as the sum of


the diffusion term (D2[X]

z2 ) the advection term (X

z) and the reaction term

(rxn) The variable D is the diffusion coefficient is the sedimentation rate and z thedepth away from the sediment-water interface (Boudreau 1997) The consumption ofoxygen through aerobic respiration of organic matter was parameterized as

korg[org][O2]

[O2] kO2 where korg is the reaction rate constant and kO2 the limiting

concentration for O2 The term[Mo]

zconsiders the gradient in pore water Mo

concentrations from the depth of O2 consumptionmdashand hence the onset of oxidedissolution and associated release of sorbed Momdashto the depth where Mo concentra-tions decrease to stable values within the zone of pore water sulfide accumulation Thereaction term for tetrathiomolybdate is expressed as kth [H2S] [Mo] where kth is thereaction rate constant The korg and kth were determined by calibrating the model topore water Mo and sulfide data derived from the FOAM site (table 5) Dissolved sulfidelevels were set at a constant value under conditions where oxygen has been quantita-tively consumed through respiration Further if [O2] is greater than zero [H2S] isassumed to be zero

Next we explore the sensitivity of authigenic Mo enrichments within marinesediments over a wide range of parameter space considered in figure 3 and theassociated discussionsmdashbut using FOAM site values as a baseline (fig 7 table 5) At themost basic level the delivery of organic carbon and the associated accumulation ofpore water sulfide through sulfate reduction is a requirement from the model in orderto achieve even muted authigenic Mo enrichments (figs 7D and 7E) The model issensitive to pore water Mo concentrations at the depth of O2 consumption (fig 7A)which implies that higher delivery of Mo to the sediments via oxides and burial anddiffusion of seawater will increase authigenic enrichments upon reaction of the

TABLE 5

Variables and values used for model calibration and sensitivity tests in figure 7

Parameters Values Units SourcesDissolved seawater [Mo] 150 nM (this study ndash FOAM)Dissolved seawater [O2] 150 μMMo Diffusion coefficient

(DMo)391 cm2 yr-1 (Malinovsky and others 2007)

O2 Diffusion coefficient (DO2)

621 cm2 yr-1 (Ferrell and Himmelblau 1967 Hayduk and Laudie 1974)

Sedimentation rate (ω) 02 cm yr-1 (Goldhaber and others 1977 Krishnaswami and others 1984)

Sediment porosity (φ) 08 - (Boudreau 1997)Organic rate constant (korg) 40times10-3 yr-1 (Arndt and others 2009) (this

study ndash FOAM)Thiomolybdate rate

constant (k th)1times103 mmol cm-2 yr-1 (this study ndash FOAM)

Limiting concentration forO2 (KO2)

20times10-6 mmol cm-3 (Reed and others 2011)

Organic rain flux (Forg) 03 mmol cm-2 yr-1 (this study ndash FOAM)


Fig

7D

iage

net

icm

odel

resu

lts

Bas

elin

eva

lues

(red

dot)

are

para

met

ersd

eter

min

edfr

omth

eFO

AM

site

and

are

pres

ente

din

tabl

e5

Un

less

oth

erw

ise

indi

cate

dth

em

odel

sen

siti

vity

anal

yses

use

the

FOA

Mva

lues

for

rele

van

tpar

amet

ers

We

expl

ore

the

sen

siti

vity

ofm

arin

eau

thig

enic

Mo

enri

chm

ents

todi

ssol

ved

seaw

ater

Mo

and

O2s

edim

enta

tion

rate

sor

gan

icm

atte

rra

infl

uxan

dpo

rew

ater

H2S

leve

lsov

era

wid

era

nge

ofpa

ram

eter

spac

ere

leva

ntt

oth

atco

nsi

dere

din

figu

re3


dissolved Mo with appreciable pore water sulfide As in similar previous models(Morford and others 2009) we find authigenic Mo enrichment to be most highlysensitive to sedimentation rates (figs 7A and 7C) For example sedimentation of 02cm yr1 can severely mute authigenic enrichments in marginal settings such as FOAMexplaining the observed sediment Mo concentration values (fig 6) Muted Moconcentrations have even been observed from euxinic portions of the Black Sea wheresedimentation rates are elevated (Lyons and Kashgarian 2005) Conversely particu-larly low sedimentation rates in combination with elevated pore water Mo at the depthof O2 consumption can allow for relatively elevated authigenic Mo concentrations(figs 7A and 7C) These conditions replicate the ranges of Mo concentrationsobserved from other oxic sites with pore water sulfide and elevated authigenicenrichments (fig 3) In addition if we consider a sensitivity analysis that integrates the

most extreme[Mo]

zand from Peru Margin Sites with available data (350 nM and

0025 cm yr-1 respectively Scholz and others 2011) the model provides evidencethat sedimentary Mo concentration of up to 70 ppm are possible (figs 7A and 7C)mdasharange which explains the bulk of the existing sedimentary Mo data from low oxygenenvironments (fig 3) However under no relevant conditions can the model replicatethe 100 ppm Mo found in some of these low oxygen environments (Brongersma-Sanders and others 1980 Calvert and Price 1983 Boumlning and others 2004 Scholzand others 2011 Scholz and others 2017) Such a result provides evidence that watercolumn sulfide accumulation or additional sedimentary Mo delivery parameters notconsidered in our model are likely necessary to explain the extreme elevated Moenrichments from these low oxygen settings (fig 3 Scholz and others 2017)

Lastly though sedimentation rates and sedimentary Mo delivery can explain theranges of authigenic Mo accumulation from oxic settings seasonal variations insediment chemistry not considered in our model are all likely to contribute to mutedauthigenic Mo formation Previous studies have shown that sediments with seasonalvariations in redox state metabolic rates or biogenic mixing of particles betweenredox zones of the sediments like FOAM (Goldhaber and others 1977 Aller 1980a1980b) minimize retention of authigenic Mo phases (Morford and others 2009 Wangand others 2011) At FOAM a range of previous work provides evidence thatbioturbation pore water redox and organic matter remineralization rates all varyseasonally within the upper few cm of the sediment pile (Goldhaber and others 1977Aller 1980a 1980b) Specifically lower temperatures during the winter monthsdecrease infaunal activity and metabolic rates Together these processes result inrelatively more oxidizing conditions near the sediment water interface during thewinter relative to summer through decreased upward mixing of reduced sedimentsand decreased rates of sulfate reduction with the consequence of net oxidation ofreduced sedimentary phases such as pyrite (Goldhaber and others 1977 Aller 1980a1980b Westrich and Berner 1988 Green and Aller 1998 2001) However despitethese known dynamics data generated for this study that overlap with that of previousFOAM works [S isotopes (fig 4D) dissolved Fe and Mn and sulfide sedimentary Fespeciation Mn and S concentrations] are remarkably comparable despite in somecases nearly 40 years difference in the time of our sampling (see Results section fordetails) Indeed despite temperature metabolic and faunal seasonal dynamics whichinduce non-steady state sedimentary and geochemical conditions in the upper 10cm previous seasonal observations have also proven a consistency of dissolved andsedimentary geochemical characteristics for a given season from year to year (Aller1980a 1980b) Non-steady state factors should be considered in future models butprevious studies and ours provide evidence that FOAM may be best characterized as alsquodynamic steady statersquo


conclusions

Based on observations from modern settings we provide constraints on the use ofsedimentary Fe speciation and Mo concentrations as paleoredox proxies to uniquelyidentify the presenceabsence of pore water sulfide accumulation during early diagen-esis in ancient non-euxinic water column settings To this end we compare ratios ofpyrite-to-lsquohighly reactiversquo Fe (FepyFeHR) and Mo concentrations from modern non-euxinic settings with and without observations of sedimentary pore water sulfideaccumulation We also provide original Fe speciation sedimentary Mo and S isotopedata from the FOAM site in Long Island Sound where pore water sulfide concentra-tions are in excess of 3 mM The FOAM site has played an essential role in ourunderstanding of Fe reactivity toward sulfide and the development of a commonlyapplied Fe speciation scheme (Canfield and Berner 1987 Berner and Canfield 1989Canfield and others 1992 Raiswell and Canfield 1998) and the earlier DOP approach(Berner 1970 Raiswell and others 1988 Canfield and others 1992)mdashin large partthrough proximity to Yale University and the research group of Bob Berner Givenprevious observations at FOAM and other similar localities with pore water sulfide weexpected FeHRFeT values of 038 (Raiswell and Canfield 1998) FeTAl ratios of05 (Krishnaswami and others 1984) FepyFeHR 08 and Mo concentrations 2 to25 ppm (Scott and Lyons 2012) Deviations from these predictions are explored in thecontext of the broader data compilation and sensitivity analyses of an authigenic Momodel

Iron speciation data from the literature and our new FOAM results fit thepredicted ranges with most of the lsquohighly reactiversquo Fe pool reacted with H2S to formpyrite and resulting with few exceptions in FepyFeHR values as a generally confidentindicator of the presenceabsence of pore water sulfide accumulation during earlydiagenesis Molybdenum concentrations at FOAM by contrast did not fall within thetypical range for sulfidic pore fluids (Scott and Lyons 2012) Oxic settings with porewater sulfide accumulation including FOAM commonly display Mo concentrationssimilar to detrital values hence overlapping with that observed in oxic settings lackingpore water sulfide A diagenetic model that considers pore water dissolved Mo bottomwater O2 pore water sulfide sedimentation rate and organic rain rates providesevidence that there is indeed an authigenic Mo flux to the sediments at FOAM butthat episodic and generally high sedimentation rates likely prevent expression beyondtypical lithologic values In addition low oxygen (but non-euxinic) water columnenvironmentsmdashmost prominently the Peru Marginmdashhave the potential for a largerange of Mo concentrations regardless of pore water redox overlapping with botheuxinic settings and oxic environments with pore water sulfide The additionalapplication of Fe speciation differentiates euxinic and low oxygen (non-euxinic)settings but other paleoredox proxies (for example U concentrations N isotopes Moisotopes iodine contents) are necessary to discern low oxygen environments from oxicsettings If paleoredox indicators beyond Fe speciation and Mo concentrations provideindependent constraints on oxic water column conditions Mo concentrations are agenerally reliable indicator of pore water sulfide accumulation

Overall our results confirm that Fe speciation applications to identify ancientpore water sulfide accumulation are reasonable similar to applications of Sperling andothers (2015) but point to the requirement of more nuanced considerations forsimilar applications of Mo concentrations When Fe speciation and Mo concentrationsare applied together to ancient sediments the modern framework and authigenic Momodel combined here may be used to constrain trends in pore water sulfide accumula-tion and modes and ranges of Mo delivery to non-euxinic sediments These constraintsprovide a context for tracking evolutionary trends in benthic habitation as well ascontrols on seawater sulfate and Mo concentrations through time


ACKNOWLEDGMENTSAn iron-sulfur study of the FOAM site requires acknowledgment and gratitude for

the decades of preceding work at the site fundamental to our understanding of earlydiagenesis and commonly applied paleo proxies We note first and foremost thepioneering work of the late Bob Berner His contributions as well as his explicit andimplicit anticipation of all the important next steps in iron biogeochemistry made thisstudy possible We dedicate this paper to his memory with respect admiration andgratitude Others Don Canfield and Rob Raiswell in particular are no less deserving ofacknowledgment and gratitude

DSH TWL NJP and CTR acknowledge support from the NASA AstrobiologyInstitute under Cooperative Agreement No NNA15BB03A issued through the ScienceMission Directorate Financial support was provided to NR and TWL by NSF-OCE andan appointment to the NASA Postdoctoral Program as well as to BCG via a postdoc-toral fellowship from the Agouron Institute DSH was supported by a WHOI postdoc-toral fellowship This manuscript benefited considerably from reviews from JackMiddleburg and one anonymous reviewer

REFERENCES

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Algeo T J and Tribovillard N 2009 Environmental analysis of paleoceanographic systems based onmolybdenumndashuranium covariation Chemical Geology v 268 n 3ndash4 p 211ndash225 httpsdoiorg101016jchemgeo200909001

Aller R C 1980a Diagenetic processes near the sediment-water interface of Long Island sound IDecomposition and nutrient element geochemistry (S N P) Advances in Geophysics v 22 p 237ndash350httpsdoiorg101016S0065-2687(08)60067-9

ndashndashndashndashndashndash 1980b Diagenetic processes near the sediment-water interface of Long Island Sound II Fe and MnAdvances in Geophysics v 22 p 351ndash415 httpsdoiorg101016S0065-2687(08)60068-0

Aller R C and Cochran J K 1976 234Th238U disequilibrium in near-shore sediment Particle reworkingand diagenetic time scales Earth and Planetary Science Letters v 29 n 1 p 37ndash50 httpsdoiorg1010160012-821X(76)90024-8

Aller R C Hannides A Heilbrun C and Panzeca C 2004 Coupling of early diagenetic processes andsedimentary dynamics in tropical shelf environments The Gulf of Papua deltaic complex ContinentalShelf Research v 24 n 19 p 2455ndash2486 httpsdoiorg101016jcsr200407018

Anderson T F and Raiswell R 2004 Sources and mechanisms for the enrichment of highly reactive ironin euxinic Black Sea sediments American Journal of Science v 304 n 3 p 203ndash233 httpsdoiorg102475ajs3043203

Aquilina A Homoky W B Hawkes J A Lyons T W and Mills R A 2014 Hydrothermal sediments area source of water column Fe and Mn in the Bransfield Strait Antarctica Geochimica et CosmochimicaActa v 137 p 64ndash80 httpsdoiorg101016jgca201404003

Arndt S Hetzel A and Brumsack H-J 2009 Evolution of organic matter degradation in Cretaceous blackshales inferred from authigenic barite A reaction-transport model Geochimica et Cosmochimica Actav 73 n 7 p 2000ndash2022 httpsdoiorg101016jgca200901018

Barling J and Anbar A D 2004 Molybdenum isotope fractionation during adsorption by manganeseoxides Earth and Planetary Science Letters v 217 n 3ndash4 p 315ndash329 httpsdoiorg101016S0012-821X(03)00608-3

Benninger L Aller R Cochran J and Turekian K 1979 Effects of biological sediment mixing on the210Pb chronology and trace metal distribution in a Long Island Sound sediment core Earth andPlanetary Science Letters v 43 n 2 p 241ndash259 httpsdoiorg1010160012-821X(79)90208-5

Benoit G J Turekian K K and Benninger L K 1979 Radiocarbon dating of a core from Long IslandSound Estuarine and Coastal Marine Science v 9 n 2 p 171ndash180 httpsdoiorg1010160302-3524(79)90112-9

Berner R A 1970 Sedimentary pyrite formation American Journal of Science v 268 n 1 p 1ndash23httpsdoiorg102475ajs26811

Berner R A and Canfield D E 1989 A new model for atmospheric oxygen over Phanerozoic timeAmerican Journal of Science v 289 n 4 p 333ndash361 httpsdoiorg102475ajs2894333

Berner R A and Westrich J T 1985 Bioturbation and the early diagenesis of carbon and sulfur AmericanJournal of Science v 285 n 3 p 193ndash206 httpsdoiorg102475ajs2853193

Bertine K K and Turekian K K 1973 Molybdenum in marine deposits Geochimica et CosmochimicaActa v 37 n 6 p 1415ndash1434 httpsdoiorg1010160016-7037(73)90080-X

Boumlning P Brumsack H-J Boumlttcher M E Schnetger B Kriete C Kallmeyer J and Borchers S L2004 Geochemistry of Peruvian near-surface sediments Geochimica et Cosmochimica Acta v 68 n 21p 4429ndash4451 httpsdoiorg101016jgca200404027


Boudreau B P 1997 Diagenetic models and their implementation Berlin Springer 430 pBoudreau B P and Canfield D E 1988 A provisional diagenetic model for pH in anoxic porewaters

Application to the FOAM site Journal of Marine Research v 46 n 2 p 429ndash455 httpsdoiorg101357002224088785113603

Broecker W S and Peng T-H 1982 Tracers in the Sea Palisades New York Lahmont Doherty GeologicalObservatory Eldigio Press 690 p

Brongersma-Sanders M Stephan K Kwee T G and De Bruin M 1980 Distribution of minor elementsin cores from the Southwest Africa shelf with notes on plankton and fish mortality Marine Geologyv 37 n 1ndash2 p 91ndash132 httpsdoiorg1010160025-3227(80)90013-4

Calvert S E and Price N B 1983 Geochemistry of Namibian shelf sediments in Suess E and Thiede Jeditors Coastal Upwelling Its Sediment Record NATO Conference Series v 108 p 337ndash375httpsdoiorg101007978-1-4615-6651-9_17

Canfield D E 1989 Reactive iron in marine sediments Geochimica et Cosmochimica Acta v 53 n 3p 619ndash632 httpsdoiorg1010160016-7037(89)90005-7

Canfield D E and Berner R A 1987 Dissolution and pyritization of magnetite in anoxie marinesediments Geochimica et Cosmochimica Acta v 51 n 3 p 645ndash659 httpsdoiorg1010160016-7037(87)90076-7

Canfield D E and Farquhar J 2009 Animal evolution bioturbation and the sulfate concentration of theoceans Proceedings of the National Academy of Sciences of the United States of America v 106 n 20p 8123ndash8127 httpsdoiorg101073pnas0902037106

Canfield D E and Thamdrup B 1994 The production of 34S-depleted sulfide during bacterial dispropor-tionation of elemental sulfur Science v 266 n 5193 p 1973ndash1975 httpsdoiorg101126science11540246

Canfield D E Raiswell R Westrich J T Reaves C M and Berner R A 1986 The use of chromiumreduction in the analysis of reduced inorganic sulfur in sediments and shales Chemical Geology v 54n 1ndash2 p 149ndash155 httpsdoiorg1010160009-2541(86)90078-1

Canfield D E Raiswell R and Bottrell S H 1992 The reactivity of sedimentary iron minerals towardsulfide American Journal of Science v 292 n 9 p 659ndash683 httpsdoiorg102475ajs2929659

Canfield D E Lyons T W and Raiswell R 1996 A model for iron deposition to euxinic Black Seasediments American Journal of Science v 296 n 7 p 818 ndash 834 httpsdoiorg102475ajs2967818

Canfield D E Poulton S W and Narbonne G M 2007 Late-Neoproterozoic deep-ocean oxygenationand the rise of animal life Science v 315 n 5808 p 92ndash95 httpsdoiorg101126science1135013

Chappaz A Lyons T W Gregory D D Reinhard C T Gill B C Li C and Large R R 2014 Doespyrite act as an important host for molybdenum in modern and ancient euxinic sediments Geochimicaet Cosmochimica Acta v 126 p 112ndash122 httpsdoiorg101016jgca201310028

Cline J D 1969 Spectrophotometric determination of hydrogen sulfide in natural waters Limnology andOceanography v 14 n 3 p 454ndash458 httpsdoiorg104319lo19691430454

Cole D B Zhang S and Planavsky N J 2017 A new estimate of detrital redox-sensitive metalconcentrations and variability in fluxes to marine sediments Geochimica et Cosmochimica Acta v 215p 337ndash353 httpsdoiorg101016jgca201708004

Dahl T Chappaz A Hoek J McKenzie C J Svane S and Canfield D 2017 Evidence of molybdenumassociation with particulate organic matter under sulfidic conditions Geobiology v 15 n 2 p 311ndash323httpsdoiorg101111gbi12220

Emerson S R and Huested S S 1991 Ocean anoxia and the concentrations of molybdenum andvanadium in seawater Marine Chemistry v 34 n 3ndash4 p 177ndash196 httpsdoiorg1010160304-4203(91)90002-E

Erickson B E and Helz G R 2000 Molybdenum (VI) speciation in sulfidic waters Stability and lability ofthiomolybdates Geochimica et Cosmochimica Acta v 64 n 7 p 1149ndash1158 httpsdoiorg101016S0016-7037(99)00423-8

Ferdelman T G ms 1988 The distribution of sulfur iron manganese copper and uranium in a salt marshsediment core as determined by a sequential extraction method Delaware University of Delaware MSthesis 244 p

Ferrell R T and Himmelblau D M 1967 Diffusion coefficients of nitrogen and oxygen in water Journalof Chemical and Engineering Data v 12 n 1 p 111ndash115 httpsdoiorg101021je60032a036

Forrest J and Newman L 1977 Silver-110 microgram sulfate analysis for the short time resolution ofambient levels of sulfur aerosol Analytical Chemistry v 49 n 11 p 1579ndash1584 httpsdoiorg101021ac50019a030

Gill B C Lyons T W Young S A Kump L R Knoll A H and Saltzman M R 2011 Geochemicalevidence for widespread euxinia in the Later Cambrian ocean Nature v 469 p 80ndash83 httpsdoiorg101038nature09700

Goldberg T Archer C Vance D Thamdrup B McAnena A and Poulton S W 2012 Controls on Moisotope fractionations in a Mn-rich anoxic marine sediment Gullmar Fjord Sweden Chemical Geologyv 296ndash297 p 73ndash82 httpsdoiorg101016jchemgeo201112020

Goldhaber M B Aller R C Cochran J K Rosenfeld J K Martens C S and Berner R A 1977 Sulfatereduction diffusion and bioturbation in Long Island Sound sediments Report of the FOAM GroupAmerican Journal of Science v 277 n 3 p 193ndash237 httpsdoiorg102475ajs2773193

Green M A and Aller R C 1998 Seasonal patterns of carbonate diagenesis in nearshore terrigenousmuds Relation to spring phytoplankton bloom and temperature Journal of Marine Research v 56n 5 p 1097ndash1123 httpsdoiorg101357002224098765173473

ndashndashndashndashndashndash 2001 Early diagenesis of calcium carbonate in Long Island Sound sediments Benthic fluxes of Ca2


and minor elements during seasonal periods of net dissolution Journal of Marine Research v 59 n 5p 769ndash794 httpsdoiorg101357002224001762674935

Hardisty D S Riedinger N Planavsky N J Asael D Andren T Joslashrgensen B B and Lyons T W 2016A Holocene history of dynamic water column redox conditions in the Landsort Deep Baltic SeaAmerican Journal of Science v 316 n 8 p 713ndash745 httpsdoiorg 10247508201601

Hayduk W and Laudie H 1974 Prediction of diffusion coefficients for nonelectrolytes in dilute aqueoussolutions AIChE Journal v 20 n 3 p 611ndash615 httpsdoiorg101002aic690200329

Helz G R Miller C V Charnock J M Mosselmans J F W Pattrick R A D Garner C D andVaughan D J 1996 Mechanism of molybdenum removal from the sea and its concentration in blackshales EXAFS evidence Geochimica et Cosmochimica Acta v 60 n 19 p 3631ndash3642 httpsdoiorg1010160016-7037(96)00195-0

Helz G R Bura-Nakic E Mikac N and Ciglenecki I 2011 New model for molybdenum behavior ineuxinic waters Chemical Geology v 284 n 3ndash4 p 323ndash332 httpsdoiorg101016jchemgeo201103012

Henkel S Kasten S Poulton S W and Staubwasser M 2016 Determination of the stable iron isotopiccomposition of sequentially leached iron phases in marine sediments Chemical Geology v 421p 93ndash102 httpsdoiorg101016jchemgeo201512003

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Johnston D T Farquhar J Habicht K S and Canfield D E 2008 Sulphur isotopes and the search forlife Strategies for identifying sulphur metabolisms in the rock record and beyond Geobiology v 6 n 5p 425ndash435 httpsdoiorg101111j1472-4669200800171x

Johnston D T Poulton S W Goldberg T Sergeev V N Podkovyrov V Vorobrsquoeva N G Bekker Aand Knoll A H 2012 Late Ediacaran redox stability and metazoan evolution Earth and PlanetaryScience Letters v 335ndash336 p 25ndash35 httpsdoiorg101016jepsl201205010

Kalil E K and Goldhaber M 1973 A sediment squeezer for removal of pore waters without air contactJournal of Sedimentary Research v 43 n 2 p 553ndash557 httpsdoiorg10130674D727E8-2B21-11D7-8648000102C1865D

Kendall B Reinhard C T Lyons T W Kaufman A J Poulton S W and Anbar A D 2010 Pervasiveoxygenation along late Archaean ocean margins Nature Geoscience v 3 p 647ndash652 httpsdoiorg101038ngeo942

Kostka J E and Luther G W III 1994 Partitioning and speciation of solid phase iron in saltmarshsediments Geochimica et Cosmochimica Acta v 58 n 7 p 1701ndash1710 httpsdoiorg1010160016-7037(94)90531-2

Krishnaswami S Benninger L K Aller R C and Von Damm K L 1980 Atmospherically-derivedradionuclides as tracers of sediment mixing and accumulation in near-shore marine and lake sedi-ments Evidence from 7Be 210Pb and 239240Pu Earth and Planetary Science Letters v 47 n 3p 307ndash318 httpsdoiorg1010160012-821X(80)90017-5

Krishnaswami S Monaghan M C Westrich J Bennett J and Turekian K 1984 Chronologies ofsedimentary processes in sediments of the FOAM site Long Island Sound Connecticut AmericanJournal of Science v 284 n 6 p 706ndash733 httpsdoiorg102475ajs2846706

Lee Y J and Lwiza K 2005 Interannual variability of temperature and salinity in shallow water LongIsland Sound New York Journal of Geophysical Research Oceans v 110 httpsdoiorg1010292004JC002507

Lee Y J and Lwiza K M M 2008 Characteristics of bottom dissolved oxygen in Long Island Sound NewYork Estuarine Coastal and Shelf Science v 76 n 2 p 187ndash200 httpsdoiorg101016jecss200707001

Li C Love G D Lyons T W Fike D A Sessions A L and Chu X 2010 A stratified redox model forthe Ediacaran ocean Science v 328 n 5974 p 80ndash83 httpsdoiorg101126science1182369

Lyons T W 1997 Sulfur isotopic trends and pathways of iron sulfide formation in upper Holocenesediments of the anoxic Black Sea Geochimica et Cosmochimica Acta v 61 n 16 p 3367ndash3382httpsdoiorg101016S0016-7037(97)00174-9

Lyons T W and Kashgarian M 2005 Paradigm Lost Paradigm Found Oceanography v 18 n 2p 86ndash99 httpsdoiorg105670oceanog200544

Lyons T W and Severmann S 2006 A critical look at iron paleoredox proxies New insights from moderneuxinic marine basins Geochimica et Cosmochimica Acta v 70 n 23 p 5698ndash5722 httpsdoiorg101016jgca200608021

Lyons T W Werne J P Hollander D J and Murray R 2003 Contrasting sulfur geochemistry and FeAland MoAl ratios across the last oxic-to-anoxic transition in the Cariaco Basin Venezuela ChemicalGeology v 195 n 1ndash4 p 131ndash157 httpsdoiorg101016S0009-2541(02)00392-3

Malcolm S 1985 Early diagenesis of molybdenum in estuarine sediments Marine Chemistry v 16 n 3p 213ndash225 httpsdoiorg1010160304-4203(85)90062-3

Malinovsky D Baxter D C and Rodushkin I 2007 Ion-specific isotopic fractionation of molybdenumduring diffusion in aqueous solutions Environmental Science amp Technology v 41 p 1596ndash1600httpsdoiorg101021es062000q

Maumlrz C Poulton S W Beckmann B Kuster K Wagner T and Kasten S 2008 Redox sensitivity of Pcycling during marine black shale formation Dynamics of sulfidic and anoxic non-sulfidic bottomwaters Geochimica et Cosmochimica Acta v 72 n 15 p 3703ndash3717 httpsdoiorg101016jgca200804025

Maumlrz C Poulton S W Brumsack H-J and Wagner T 2012 Climate-controlled variability of iron


deposition in the Central Arctic Ocean (southern Mendeleev Ridge) over the last 130000 yearsChemical Geology v 330ndash331 p 116ndash126 httpsdoiorg101016jchemgeo201208015

McLennan S M 2001 Relationships between the trace element composition of sedimentary rocks andupper continental crust Geochemistry Geophysics Geosystems v 2 n 4 httpsdoiorg1010292000GC000109

McManus J Berelson W M Severmann S Poulson R L Hammond D E Klinkhammer G P andHolm C 2006 Molybdenum and uranium geochemistry in continental margin sediments Paleoproxypotential Geochimica et Cosmochimica Acta v 70 n 5 p 4643ndash4662 httpsdoiorg101016jgca2006061564

Miller C A Peucker-Ehrenbrink B Walker B D and Marcantonio F 2011 Re-assessing the surfacecycling of molybdenum and rhenium Geochimica et Cosmochimica Acta v 75 n 22 p 7146ndash7179httpsdoiorg101016jgca201109005

Morford J L and Emerson S 1999 The geochemistry of redox sensitive trace metals in sedimentsGeochimica et Cosmochimica Acta v 63 n 11ndash12 p 1735ndash1750 httpsdoiorg101016S0016-7037(99)00126-X

Morford J L Martin W R Kalnejais L H Francois R Bothner M and Karle I-M 2007 Insights ongeochemical cycling of U Re and Mo from seasonal sampling in Boston Harbor Massachusetts USAGeochimica et Cosmochimica Acta v 71 n 4 p 895ndash917 httpsdoiorg101016jgca200610016

Morford J L Martin W R Francois R and Carney C M 2009 A model for uranium rhenium andmolybdenum diagenesis in marine sediments based on results from coastal locations Geochimicaet Cosmochimica Acta v 73 n 10 p 2938ndash2960 httpsdoiorg101016jgca200902029

Nameroff T Balistrieri L S and Murray J W 2002 Suboxic trace metal geochemistry in the easterntropical North Pacific Geochimica et Cosmochimica Acta v 66 n 7 p 1139ndash1158 httpsdoiorg101016S0016-7037(01)00843-2

Owens J D Lyons T W Hardisty D S Lowery C M Lu Z Lee B and Jenkyns H C 2017 Patterns oflocal and global redox variability during the CenomanianndashTuronian Boundary Event (Oceanic AnoxicEvent 2) recorded in carbonates and shales from central Italy Sedimentology v 64 n 1 p 168ndash185httpsdoiorg101111sed12352

Pedersen T F 1985 Early diagenesis of copper and molybdenum in mine tailings and natural sediments inRupert and Holberg inlets British Columbia Canadian Journal of Earth Sciences v 22 p 1474ndash1484httpsdoiorg101139e85-153

Peketi A Mazumdar A Joao H Patil D Usapkar A and Dewangan P 2015 Coupled CndashSndashFegeochemistry in a rapidly accumulating marine sedimentary system Diagenetic and depositionalimplications Geochemistry Geophysics Geosystems v 16 n 9 p 2865ndash2883 httpsdoiorg1010022015GC005754

Planavsky N J McGoldrick P Scott C T Li C Reinhard C T Kelly A E Chu X Bekker A LoveG D and Lyons T W 2011 Widespread iron-rich conditions in the mid-Proterozoic ocean Naturev 477 p 448ndash451 httpsdoiorg101038nature10327

Poulson Brucker R L McManus J Severmann S and Berelson W M 2009 Molybdenum behaviorduring early diagenesis Insights from Mo isotopes Geochemistry Geophysics Geosystems v 10 n 6httpsdoiorg1010292008GC002180

Poulson R L Siebert C McManus J and Berelson W M 2006 Authigenic molybdenum isotopesignatures in marine sediments Geology v 34 n 8 p 617ndash620 httpsdoiorg101130G224851

Poulton S W and Canfield D E 2005 Development of a sequential extraction procedure for ironImplications for iron partitioning in continentally derived particulates Chemical Geology v 214n 3ndash4 p 209ndash221 httpsdoiorg101016jchemgeo200409003

ndashndashndashndashndashndash 2011 Ferruginous conditions A dominant feature of the ocean through Earthrsquos history Elements v 7n 2 p 107ndash112 httpsdoiorg102113gselements72107

Poulton S W and Raiswell R 2002 The low-temperature geochemical cycle of iron From continentalfluxes to marine sediment deposition American Journal of Science v 302 n 9 p 774ndash805httpsdoiorg102475ajs3029774

Poulton S W Fralick P W and Canfield D E 2004 The transition to a sulphidic ocean 184 billionyears ago Nature v 431 p 173ndash177 httpsdoiorg101038nature02912

Raiswell R and Anderson T F 2005 Reactive iron enrichment in sediments deposited beneath euxinicbottom waters Constraints on supply by shelf recycling Geological Society London Special Publica-tions v 248 p 179ndash194 httpsdoiorg101144GSLSP20052480110

Raiswell R and Canfield D E 1998 Sources of iron for pyrite formation in marine sediments AmericanJournal of Science v 298 n 3 p 219ndash245 httpsdoiorg102475ajs2983219

Raiswell R Buckley F Berner R A and Anderson T F 1988 Degree of pyritization of iron as apaleoenvironmental indicator of bottom-water oxygenation Journal of Sedimentary Research v 58n 5 p 812ndash819 httpsdoiorg101306212F8E72-2B24-11D7-8648000102C1865D

Raiswell R Canfield D E and Berner R A 1994 A comparison of iron extraction methods for thedetermination of degree of pyritisation and the recognition of iron-limited pyrite formation ChemicalGeology v 111 n 1ndash4 p 101ndash110 httpsdoiorg1010160009-2541(94)90084-1

Raiswell R Vu H P Brinza L and Benning L G 2010 The determination of labile Fe in ferrihydrite byascorbic acid extraction Methodology dissolution kinetics and loss of solubility with age and de-watering Chemical Geology v 278 p 70ndash79

Raiswell R Hardisty D S Lyons T W Canfield D E Owens J D Planavsky N J Poulton S W andReinhard C T 2018 The iron paleoredox proxies A guide to the pitfalls problems and properpractice American Journal of Science v 318 n 5 p httpsdoiorg10247505201803

Raven M R Sessions A L Fischer W W and Adkins J F 2016 Sedimentary pyrite 34S differs from


porewater sulfide in Santa Barbara Basin Proposed role of organic sulfur Geochimica et CosmochimicaActa v 186 p 120ndash134 httpsdoiorg101016jgca201604037

Reed D C Slomp C P and Gustafsson B G 2011 Sedimentary phosphorus dynamics and the evolutionof bottomwater hypoxia A coupled benthicndashpelagic model of a coastal system Limnology andOceanography v 56 n 3 p 1075ndash1092 httpsdoiorg104319lo20115631075

Reinhard C T Raiswell R Scott C Anbar A D and Lyons T W 2009 A late Archean sulfidic seastimulated by early oxidative weathering of the continents Science v 326 n 5953 p 713ndash716httpsdoiorg101126science1176711

Riedinger N Brunner B Krastel S Arnold G L Wehrmann L M Formolo M J Beck A Bates S MHenkel S Kasten S and Lyons T W 2017 Sulfur cycling in an iron oxide-dominated dynamicmarine depositional system The Argentine continental margin Frontiers in Earth Science article 33httpsdoiorg103389feart201700033

Scholz F Hensen C Noffke A Rohde A Liebetrau V and Wallmann K 2011 Early diagenesis ofredox-sensitive trace metals in the Peru upwelling areandashresponse to ENSO-related oxygen fluctuationsin the water column Geochimica et Cosmochimica Acta v 75 n 22 p 7257ndash7276 httpsdoiorg101016jgca201108007

Scholz F Severmann S McManus J and Hensen C 2014a Beyond the Black Sea paradigm Thesedimentary fingerprint of an open-marine iron shuttle Geochimica et Cosmochimica Acta v 127p 368ndash380 httpsdoiorg101016jgca201311041

Scholz F Severmann S McManus J Noffke A Lomnitz U and Hensen C 2014b On the isotopecomposition of reactive iron in marine sediments Redox shuttle versus early diagenesis ChemicalGeology v 389 p 48ndash59 httpsdoiorg101016jchemgeo201409009

Scholz F Loumlscher C R Fiskal A Sommer S Hensen C Lomnitz U Wuttig K Goumlttlicher J KosselE Steininger R and Canfield D E 2016 Nitrate-dependent iron oxidation limits iron transport inanoxic ocean regions Earth and Planetary Science Letters v 454 p 272ndash281 httpsdoiorg101016jepsl201609025

Scholz F Siebert C Dale A W and Frank M 2017 Intense molybdenum accumulation in sedimentsunderneath a nitrogenous water column and implications for the reconstruction of paleo-redoxconditions based on molybdenum isotopes Geochimica et Cosmochimica Acta v 213 p 400ndash417httpsdoiorg101016jgca201706048

Scott C and Lyons T W 2012 Contrasting molybdenum cycling and isotopic properties in euxinic versusnon-euxinic sediments and sedimentary rocks Refining the paleoproxies Chemical Geologyv 324ndash325 p 19ndash27 httpsdoiorg101016jchemgeo201205012

Scott C Lyons T W Bekker A Shen Y Poulton S W Chu X and Anbar A D 2008 Tracing thestepwise oxygenation of the Proterozoic ocean Nature v 452 p 456ndash459 httpsdoiorg101038nature06811

Scott C T Bekker A Reinhard C T Schnetger B Krapež B Rumble D III and Lyons T W 2011Late Archean euxinic conditions before the rise of atmospheric oxygen Geology v 39 n 2 p 119ndash122httpsdoiorg101130G315711

SeebergElverfeldt J Schluter M Feseker T and Koumllling M 2005 Rhizon sampling of porewaters nearthe sedimentwater interface of aquatic systems Limnology and oceanography Methods v 3 n 8p 361ndash371 httpsdoiorg104319lom20053361

Severmann S Lyons T W Anbar A McManus J and Gordon G 2008 Modern iron isotope perspectiveon the benthic iron shuttle and the redox evolution of ancient oceans Geology v 36 n 6 p 487ndash490httpsdoiorg101130G24670A1

Severmann S McManus J Berelson W M and Hammond D E 2010 The continental shelf benthiciron flux and its isotope composition Geochimica et Cosmochimica Acta v 74 n 14 p 3984ndash4004httpsdoiorg101016jgca201004022

Shimmield G B and Price N B 1986 The behaviour of molybdenum and manganese during earlysediment diagenesismdashoffshore Baja California Mexico Marine Chemistry v 19 n 3 p 261ndash280httpsdoiorg1010160304-4203(86)90027-7

Sperling E A Wolock C J Morgan A S Gill B C Kunzmann M Halverson G P Macdonald F AKnoll A H and Johnston D T 2015 Statistical analysis of iron geochemical data suggests limited lateProterozoic oxygenation Nature v 523 p 451ndash454 httpsdoiorg101038nature14589

Sundby B Martinez P and Gobeil C 2004 Comparative geochemistry of cadmium rhenium uraniumand molybdenum in continental margin sediments Geochimica et Cosmochimica Acta v 68 n 11p 2485ndash2493 httpsdoiorg101016jgca200308011

Tarhan L G Droser M L Planavsky N J and Johnston D T 2015 Protracted development ofbioturbation through the early Palaeozoic Era Nature Geoscience v 8 p 865ndash869 httpsdoiorg101038ngeo2537

Taylor S R and McLennan S M 1995 The geochemical evolution of the continental crust Reviews ofGeophysics v 33 p 241ndash265 httpsdoiorg10102995RG00262

Turekian K K and Wedepohl K H 1961 Distribution of the elements in some major units of the earthrsquoscrust Geological Society of America Bulletin v 72 n 2 p 175ndash192 httpsdoiorg1011300016-7606(1961)72[175DOTEIS]20CO2

Wagner M Chappaz A and Lyons T W 2017 Molybdenum speciation and burial pathway in weaklysulfidic environments Insights from XAFS Geochimica et Cosmochimica Acta v 206 p 18ndash29httpsdoiorg101016jgca201702018

Wallace R B Baumann H Grear J S Aller R C and Gobler C J 2014 Coastal ocean acidificationThe other eutrophication problem Estuarine Coastal and Shelf Science v 148 p 1ndash13 httpsdoiorg101016jecss201405027

Wang D Aller R C and Sanudo-Wilhelmy S A 2011 Redox speciation and early diagenetic behavior of


dissolved molybdenum in sulfidic muds Marine Chemistry v 125 n 1ndash4 p 101ndash107 httpsdoiorg101016jmarchem201103002

Wehrmann L M Formolo M J Owens J D Raiswell R Ferdelman T G Riedinger N and LyonsT W 2014 Iron and manganese speciation and cycling in glacially influenced high-latitude fjordsediments (West Spitsbergen Svalbard) Evidence for a benthic recycling-transport mechanismGeochimica et Cosmochimica Acta v 141 p 628ndash655 httpsdoiorg101016jgca201406007

Westrich J T ms 1983 The consequences and controls of bacterial sulfate reduction in marine sedimentsNew Haven Connecticut Yale University Ph D thesis 530 p

Westrich J T and Berner R A 1988 The effect of temperature on rates of sulfate reduction in marinesediments Geomicrobiology Journal v 6 n 2 p 99ndash117 httpsdoiorg10108001490458809377828

Wijsman J W M Middelburg J J and Heip C H R 2001 Reactive iron in Black Sea sedimentsImplications for iron cycling Marine Geology v 172 n 3ndash4 p 167ndash180 httpsdoiorg101016S0025-3227(00)00122-5

Zheng Y Anderson R F van Geen A and Kuwabara J 2000 Authigenic molybdenum formation inmarine sediments A link to pore water sulfide in the Santa Barbara Basin Geochimica et CosmochimicaActa v 64 n 25 p 4165ndash4178 httpsdoiorg101016S0016-7037(00)00495-6

Zhou X Jenkyns H C Lu W Hardisty D S Owens J D Lyons T W and Lu Z 2017 Organicallybound iodine as a bottom-water redox proxy Preliminary validation and application ChemicalGeology v 457 p 95ndash106 httpsdoiorg101016jchemgeo201703016

Zhu M-X Hao X-C Shi X-N Yang G-P and Li T 2012 Speciation and spatial distribution ofsolid-phase iron in surface sediments of the East China Sea continental shelf Applied Geochemistryv 27 n 4 p 892ndash905 httpsdoiorg101016japgeochem201201004

Zhu M-X Huang X-L Yang G-P and Chen L-J 2015 Iron geochemistry in surface sediments of atemperate semi-enclosed bay North China Estuarine Coastal and Shelf Science v 165 p 25ndash35httpsdoiorg101016jecss201508018

556 D Hardisty and others

identifying paleo-pore water sulfide accumulation in ancient settings and linkedprocesses regulating seawater Mo and sulfate concentrations and delivery to sedi-ments Among other utilities identifying ancient accumulation of sulfide in porewaters particularly beneath oxic bottom waters constrains the likelihood that thosesettings could have hosted organisms and ecosystems with thiotrophy at their founda-tions

Key words paleoredox iron speciation molybdenum pore water sulfide LongIsland Sound

introduction

Iron speciation and molybdenum concentrations have been well calibrated inmodern settings for recognizing end-member euxinic (anoxic and H2S-containing)and ferruginous (anoxic and iron-rich) settings in the geologic record (Berner 1970Raiswell and others 1988 Canfield and others 1992 Canfield and others 1996Raiswell and Canfield 1998 Poulton and Canfield 2005 2011 Lyons and Severmann2006 Algeo and Lyons 2006 Raiswell and others 2018) This past research hasresulted in extensive application of these proxies toward an improved understandingof water column redox evolution and dynamics through time including Phanerozoicocean anoxic events (Maumlrz and others 2008 Gill and others 2011) the Proterozoic(Poulton and others 2004 Canfield and others 2007 Scott and others 2008 Li andothers 2010 Planavsky and others 2011 Johnston and others 2012 Sperling andothers 2015) and the Archean (Reinhard and others 2009 Kendall and others 2010Scott and others 2011) Beyond the recognition of ancient euxinic and ferruginouswater columns more recent research has provided a context for using Fe and Moproxies to infer accumulation of sulfidic pore waters in ancient sediments includingthose deposited beneath water columns lacking dissolved sulfide and Fe (Scott andLyons 2012 Sperling and others 2015) Refined recognition of these conditions hasimportant implications for the evolution of the marine sulfate reservoir and forinterpretation of the geochemical impacts of sediment mixing induced by benthicinfaunal communities through time (Canfield and Farquhar 2009 Tarhan and others2015) Additionally pore water sulfide has implications for bottom water habitabilityand the evolution of thiotrophy and associated symbiotic relationships among com-bined micro-macrofaunal communities (Sperling and others 2015 Tarhan andothers 2015) However although a broad framework currently exists for understand-ing the conditions leading to Mo and Fe fixation in sulfidic sediments (see back-ground) few studies have systematically evaluated proxy expressions from modernsediments to assess their potential as uniquely pore fluid indicators of paleoredox inancient sediments

Here we specifically assess the paleoredox proxy potential of Fe speciation andMo concentrations to recognize the presence or absence of pore water sulfideaccumulation during early diagenesis from modern marine sediments underlyingwater columns without stable euxinia and a range of ambient oxygen concentrationsThis endeavor is grounded in a broad context provided by compilations of Fespeciation and Mo concentrations from modern localities where water column andpore water redox conditions are well characterized In addition we present an originalcase study with Fe-speciation Mo concentration and S concentration and isotope datafor sediments from the oxic FOAM (Friends of Anoxic Mud) site in Long Island Sound(LIS) USA where sedimentary pore fluids are well-known to host elevated andpersistent pore water sulfide concentrations Previous studies of LIS including theFOAM site have been fundamental to the initial development of the Fe paleoredoxproxies and a range of other sedimentary geochemical signatures (Aller and Cochran1976 Goldhaber and others 1977 Benninger and others 1979 Benoit and others















2 to MoS42 is




























33S 33S [(34S1000 1)0515 1] 13 1000 (2)






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nin

tabl

es1

and

2



TABLE 1




TABLE 2



2 2187 00324 2144 00418 2398 003612 3735 0113 -1895 014916 3600 0104 -1948 015520 3797 0122 -1780 015924 4216 0115 -1707 017928 4363 011732 4428 011936 4365 010240 4380 0116



TA

BL

E3

Res

ults

for

Fe

spec

iati

on

degr

eeof

pyri

tiza

tion

(DO

P)

bulk

sedi

men

tary

Fe

and

Al

conc

entr

atio

ns

and

tota

lor

gani

cca

rbon

(TO

C)

Dep

th

(cm

)Fe

asc

(wt

)Fe

dith

(wt

)Fe

mag

(wt

)Fe

py(w

t )

FeH

Cl(

wt

)

FeT

(wt

)A

l T(w

t )

FeH

RF

e TFe

pyF

e HR

FeTA

lD

OP

TO

C(w

t )

05

002

lt D

L

009

068

137

318

582

025

086

055

033

175

2ltD

L

011

006

065

114

344

661

024

079

052

036

185

40

060

130

050

311

183

166

430

180

550

490

211

206

003

010

006

036

133

296

567

019

065

052

022

122

80

010

040

020

351

053

136

450

140

840

480

251

3110

001

003

002

060

094

272

551

024

091

049

039

101

120

010

020

060

661

022

775

710

270

860

480

392

5014

lt D

L

lt D

L

001

074

116

303

603

025

098

050

039

121

160

010

020

010

650

943

116

190

220

940

500

410

7118

002

003

003

069

100

253

495

031

089

051

041

104

200

050

040

070

711

253

216

040

270

820

530

361

3222

lt D

L

lt D

L

006

093

092

332

667

030

094

050

050

142

240

01lt

DL

0

051

061

243

124

850

360

950

640

461

5226

lt D

L

lt D

L

007

083

112

369

738

024

093

050

043

165

28lt

DL

lt

DL

0

040

931

513

457

010

280

960

490

381

2430

lt D

L

lt D

L

002

086

097

303

569

028

099

053

047

145

320

040

020

080

681

213

176

120

260

830

520

361

4134

003

001

008

059

124

279

589

026

083

047

032

087

36lt

DL

lt

DL

0

030

701

103

196

090

230

960

520

391

5438

lt D

L

001

007

069

120

306

587

025

090

052

036

191

400

030

030

080

661

173

005

730

270

830

520

361

0042

002

001

006

055

114

328

647

019

087

051

033

147

440

020

010

070

711

133

045

700

270

880

530

391

6446

001

lt D

L

009

081

099

331

648

027

089

051

045

149

480

020

010

060

600

773

165

840

220

860

540

441

4250

lt D

L

lt D

L

002

085

084

284

522

031

097

054

050

127

DL

D

etec

tion

lim

it

The

data

are

pres

ente

din

figu

re5


Fig

5(A

)D

isso

lved

pore

wat

erFe

con

cen

trat

ion

s(B

)di

thio

nit

eFe

toto

tal

Fera

tios

(Fe d

ithF

e T)

(C)

degr

eeof

pyri

tiza

tion

(DO

P)a

nd

(D)

rati

osof

hig

hly

reac

tive

Feto

tota

lFe

con

cen

trat

ion

s(F

e HRF

e T)

tota

lFe

toA

lrat

ios

(Fe T

Al T

)an

dpy

riti

zed

Feov

erh

igh

lyre

acti

veFe

(Fe p

yFe

HR)

Th

eve

rtic

alba

rre

pres

ents

the

ran

geof

DO

Ppr

evio

usly

mea

sure

dat

FOA

Mfr

omC

anfi

eld

and

oth

ers

(199

2)



discussion






Fig

6Se

dim

enta

ry(A

)M

oco

nce

ntr

atio

ns

(B)

Mo

Alm

assr

atio

s(C

)po

rew

ater

Mo

con

cen

trat

ion

s(D

)se

dim

enta

ryM

nco

nce

ntr

atio

ns

and

(E)

pore

wat

erM

nco

nce

ntr

atio

ns

Hor

izon

tald

ash

edlin

esre

pres

entt

he

dept

hof

sign

ifica

nts

ulfi

deac

cum

ulat

ion

Sh

aded

area

srep

rese

ntM

oA

lave

rage

shal

eva

lues

from

Tur

ekia

nan

dW

edep

ohl(

1961

)




TABLE 4


Depth (cm)

Pore water Mo (nM)

Bulk Mo (ppm)

05 1574 11 2 1398 11 4 11 6 2965 10 8 10

10 799 10 12 12 14 1151 10 16 13 18 359 11 20 09 22 30 24 09 26 45 28 10 30 139 10 32 09 34 36 10 38 342 09 40 11 42 144 10 44 10 46 148 11 48 10 50 84 12




















[X]t

D2[X]

z2 [X]

z rxn (4)







korg[org][O2]






TABLE 5














Fig

7D

iage

net

icm

odel

resu

lts

Bas

elin

eva

lues

(red

dot)

are

para

met

ersd

eter

min

edfr

omth

eFO

AM

site

and

are

pres

ente

din

tabl

e5

Un

less

oth

erw

ise

indi

cate

dth

em

odel

sen

siti

vity

anal

yses

use

the

FOA

Mva

lues

for

rele

van

tpar

amet

ers

We

expl

ore

the

sen

siti

vity

ofm

arin

eau

thig

enic

Mo

enri

chm

ents

todi

ssol

ved

seaw

ater

Mo

and

O2s

edim

enta

tion

rate

sor

gan

icm

atte

rra

infl

uxan

dpo

rew

ater

H2S

leve

lsov

era

wid

era

nge

ofpa

ram

eter

spac

ere

leva

ntt

oth

atco

nsi

dere

din

figu

re3



most extreme[Mo]





conclusions








REFERENCES



















































































































































2 to MoS42 is




























33S 33S [(34S1000 1)0515 1] 13 1000 (2)






Fig

2C

ompi

lati

onof

Fesp

ecia

tion

data

from

mod

ern

sedi

men

ts

(A)

Non

-eux

inic

wat

erco

lum

ns

wit

h(C

anfi

eld

1989

Sc

hol

zan

dot

her

s20

14b

Rav

enan

dot

her

s20

16R

iedi

nge

ran

dot

her

s20

17)

and

wit

hou

t(C

anfi

eld

1989

Wijs

man

and

oth

ers

2001

Alle

ran

dot

her

s20

04G

oldb

erg

and

oth

ers

2012

Sch

olz

and

oth

ers

2014

bW

ehrm

ann

and

oth

ers

2014

Hen

kela

nd

oth

ers

2016

Rie

din

ger

and

oth

ers

2017

)po

rew

ater

sulfi

dein

the

hos

tsed

imen

ts(

B)

Eux

inic

(Rai

swel

lan

dC

anfi

eld

1998

Wijs

man

and

oth

ers

2001

Lyo

ns

and

oth

ers

2003

)lo

wox

ygen

(Rai

swel

lan

dC

anfi

eld

1998

Sch

olz

and

oth

ers

2014

bR

aven

and

oth

ers

2016

)an

dox

icw

ater

colu

mn

s(C

anfi

eld

1989

Rai

swel

lan

dC

anfi

eld

1998

Alle

ran

dot

her

s20

04G

oldb

erg

and

oth

ers

2012

Maumlr

zan

dot

her

s20

12Z

hu

and

oth

ers

2012

Aqu

ilin

aan

dot

her

s20

14S

chol

zan

dot

her

s20

14b

Weh

rman

nan

dot

her

s20

14P

eket

ian

dot

her

s20

15Z

hu

and

oth

ers

2015

Hen

kela

nd

oth

ers

2016

Rie

din

ger

and

oth

ers

2017

)L

owox

ygen

isde

fin

edas

15

M

O2

butl

acki

ng

dete

cted

sulfi

deN

otab

lyt

he

lsquohig

hly

reac

tive

rsquoFe

isde

term

ined

diff

eren

tly

betw

een

the

publ

icat

ion

sin

clud

ing

the

sequ

enti

alex

trac

tion

ofPo

ulto

nan

dC

anfi

eld

(200

5)i

tspr

edec

esso

rs(f

orex

ampl

eR

aisw

ella

nd

Can

fiel

d19

98A

ller

and

oth

ers

2004

)an

dot

her

mod

ifica

tion

s(f

orex

ampl

eR

aven

and

oth

ers

2016

)W

hen

avai

labl

eFe

py

FeH

Rin

clud

esir

onfr

omth

eac

idvo

lati

leS

extr

acti

onin

the

num

erat

orT

he

hor

izon

tall

ine

repr

esen

tsth

esu

gges

ted

boun

dary

for

oxic

wat

erco

lum

nco

ndi

tion

sfo

rm

oder

nse

dim

ents

03

8(C

anfi

eld

and

Rai

swel

l19

98)

Th

eve

rtic

allin

ere

pres

ents

the

Fep

yFe

HR

boun

dary

for

indi

cati

onof

sulfi

deac

cum

ulat

ion

of0

7w

hic

his

disc

usse

din

the

mai

nte

xtT

he

solid

bars

repr

esen

t1

ofth

ere

spec

tive

data


Fig

3B

oxan

dw

his

ker

plot

sco

mpa

rin

gse

dim

enta

ryM

oco

nce

ntr

atio

ns

from

(A

)O

xic

wat

erco

lum

nse

ttin

gsw

ith

(Mal

colm

198

5Pe

ders

en1

985

Mor

ford

and

oth

ers

2007

Po

ulso

nB

ruck

eran

dot

her

s20

09)

and

wit

hou

t(Z

hen

gan

dot

her

s20

00

Boumln

ing

and

oth

ers

2004

M

orfo

rdan

dot

her

s20

09

Poul

son

Bru

cker

and

oth

ers

2009

Sch

olz

and

oth

ers

2011

Gol

dber

gan

dot

her

s20

12)

appr

ecia

ble

pore

wat

ersu

lfide

con

cen

trat

ion

sIn

terv

alsw

her

eM

ois

asso

ciat

edw

ith

Mn

enri

chm

ents

(2

wt

M

nin

mos

tcas

es)

are

not

incl

uded

Not

eth

edi

ffer

ence

insc

ale

inpa

rtA

rela

tive

toB

and

C(

B)

Oxi

c(M

alco

lm1

985

Pede

rsen

198

5Sh

imm

ield

and

Pric

e19

86M

orfo

rdan

dE

mer

son

199

9Z

hen

gan

dot

her

s20

00B

oumlnin

gan

dot

her

s20

04S

undb

yan

dot

her

s20

04M

cMan

usan

dot

her

s20

06P

ouls

onan

dot

her

s20

06

Mor

ford

and

oth

ers

2007

Pou

lson

Bru

cker

and

oth

ers

2009

Mor

ford

and

oth

ers

2009

Sch

olz

and

oth

ers

2011

Gol

dber

gan

dot

her

s20

12)

and

low

oxyg

enw

ater

colu

mn

s(B

ron

gers

ma-

San

ders

and

oth

ers

1980

Cal

vert

and

Pric

e19

83M

orfo

rdan

dE

mer

son

199

9Z

hen

gan

dot

her

s20

00N

amer

offa

nd

oth

ers

2002

Boumln

ing

and

oth

ers

2004

McM

anus

and

oth

ers

2006

Pou

lson

and

oth

ers

2006

Pou

lson

Bru

cker

and

oth

ers

2009

Sch

olz

and

oth

ers

2011

)mdashde

fin

edas

15

M

O2

butl

acki

ng

diss

olve

dsu

lfide

(C

)L

owox

ygen

wat

erco

lum

nsi

tes

wit

h(Z

hen

gan

dot

her

s20

00B

oumlnin

gan

dot

her

s20

04P

ouls

onB

ruck

eran

dot

her

s20

09S

chol

zan

dot

her

s20

11)

and

wit

hou

t(Z

hen

gan

dot

her

s20

00

Nam

erof

fan

dot

her

s20

02

Sch

olz

and

oth

ers

2011

)ap

prec

iabl

esu

lfide

con

cen

trat

ion

sin

the

pore

wat

ers

Ala

ckof

appr

ecia

ble

sulfi

deis

defi

ned

bysu

lfide

mea

sure

dbu

t

100

M

su

lfide

mea

sure

dbu

tbe

low

dete

ctio

n

orsu

lfide

not

mea

sure

dbu

tw

ith

elev

ated

diss

olve

dFe

con

cen

trat

ion

s


Fig

4FO

AM

con

cen

trat

ion

profi

les

for

(A)

pore

wat

ersu

lfat

ean

dh

ydro

gen

sulfi

de(

B)

tota

lor

gan

icca

rbon

(TO

C)

and

(C)

wei

ght

perc

ent

sulf

urin

pyri

te

Als

oin

clud

edar

eis

otop

eco

mpo

siti

ons

of(D

)34S

(34S)

ofsu

lfat

ean

ddi

ssol

ved

sulfi

dean

d(E

)33S

(33S)

for

sulf

ate

and

diss

olve

dsu

lfide

In

part

Dd

ata

are

show

nfr

ombo

thth

eco

res

utili

zed

for

mea

sure

men

tin

AB

CE

ofth

isfi

gure

(201

0co

re)

and

prev

ious

lyun

publ

ish

edda

tafr

omco

reFO

AM

-1(A

ller

1980

a19

80b)

Sul

fur

isot

ope

data

are

show

nin

tabl

es1

and

2



TABLE 1




TABLE 2



2 2187 00324 2144 00418 2398 003612 3735 0113 -1895 014916 3600 0104 -1948 015520 3797 0122 -1780 015924 4216 0115 -1707 017928 4363 011732 4428 011936 4365 010240 4380 0116



TA

BL

E3

Res

ults

for

Fe

spec

iati

on

degr

eeof

pyri

tiza

tion

(DO

P)

bulk

sedi

men

tary

Fe

and

Al

conc

entr

atio

ns

and

tota

lor

gani

cca

rbon

(TO

C)

Dep

th

(cm

)Fe

asc

(wt

)Fe

dith

(wt

)Fe

mag

(wt

)Fe

py(w

t )

FeH

Cl(

wt

)

FeT

(wt

)A

l T(w

t )

FeH

RF

e TFe

pyF

e HR

FeTA

lD

OP

TO

C(w

t )

05

002

lt D

L

009

068

137

318

582

025

086

055

033

175

2ltD

L

011

006

065

114

344

661

024

079

052

036

185

40

060

130

050

311

183

166

430

180

550

490

211

206

003

010

006

036

133

296

567

019

065

052

022

122

80

010

040

020

351

053

136

450

140

840

480

251

3110

001

003

002

060

094

272

551

024

091

049

039

101

120

010

020

060

661

022

775

710

270

860

480

392

5014

lt D

L

lt D

L

001

074

116

303

603

025

098

050

039

121

160

010

020

010

650

943

116

190

220

940

500

410

7118

002

003

003

069

100

253

495

031

089

051

041

104

200

050

040

070

711

253

216

040

270

820

530

361

3222

lt D

L

lt D

L

006

093

092

332

667

030

094

050

050

142

240

01lt

DL

0

051

061

243

124

850

360

950

640

461

5226

lt D

L

lt D

L

007

083

112

369

738

024

093

050

043

165

28lt

DL

lt

DL

0

040

931

513

457

010

280

960

490

381

2430

lt D

L

lt D

L

002

086

097

303

569

028

099

053

047

145

320

040

020

080

681

213

176

120

260

830

520

361

4134

003

001

008

059

124

279

589

026

083

047

032

087

36lt

DL

lt

DL

0

030

701

103

196

090

230

960

520

391

5438

lt D

L

001

007

069

120

306

587

025

090

052

036

191

400

030

030

080

661

173

005

730

270

830

520

361

0042

002

001

006

055

114

328

647

019

087

051

033

147

440

020

010

070

711

133

045

700

270

880

530

391

6446

001

lt D

L

009

081

099

331

648

027

089

051

045

149

480

020

010

060

600

773

165

840

220

860

540

441

4250

lt D

L

lt D

L

002

085

084

284

522

031

097

054

050

127

DL

D

etec

tion

lim

it

The

data

are

pres

ente

din

figu

re5


Fig

5(A

)D

isso

lved

pore

wat

erFe

con

cen

trat

ion

s(B

)di

thio

nit

eFe

toto

tal

Fera

tios

(Fe d

ithF

e T)

(C)

degr

eeof

pyri

tiza

tion

(DO

P)a

nd

(D)

rati

osof

hig

hly

reac

tive

Feto

tota

lFe

con

cen

trat

ion

s(F

e HRF

e T)

tota

lFe

toA

lrat

ios

(Fe T

Al T

)an

dpy

riti

zed

Feov

erh

igh

lyre

acti

veFe

(Fe p

yFe

HR)

Th

eve

rtic

alba

rre

pres

ents

the

ran

geof

DO

Ppr

evio

usly

mea

sure

dat

FOA

Mfr

omC

anfi

eld

and

oth

ers

(199

2)



discussion






Fig

6Se

dim

enta

ry(A

)M

oco

nce

ntr

atio

ns

(B)

Mo

Alm

assr

atio

s(C

)po

rew

ater

Mo

con

cen

trat

ion

s(D

)se

dim

enta

ryM

nco

nce

ntr

atio

ns

and

(E)

pore

wat

erM

nco

nce

ntr

atio

ns

Hor

izon

tald

ash

edlin

esre

pres

entt

he

dept

hof

sign

ifica

nts

ulfi

deac

cum

ulat

ion

Sh

aded

area

srep

rese

ntM

oA

lave

rage

shal

eva

lues

from

Tur

ekia

nan

dW

edep

ohl(

1961

)




TABLE 4


Depth (cm)

Pore water Mo (nM)

Bulk Mo (ppm)

05 1574 11 2 1398 11 4 11 6 2965 10 8 10

10 799 10 12 12 14 1151 10 16 13 18 359 11 20 09 22 30 24 09 26 45 28 10 30 139 10 32 09 34 36 10 38 342 09 40 11 42 144 10 44 10 46 148 11 48 10 50 84 12




















[X]t

D2[X]

z2 [X]

z rxn (4)







korg[org][O2]






TABLE 5














Fig

7D

iage

net

icm

odel

resu

lts

Bas

elin

eva

lues

(red

dot)

are

para

met

ersd

eter

min

edfr

omth

eFO

AM

site

and

are

pres

ente

din

tabl

e5

Un

less

oth

erw

ise

indi

cate

dth

em

odel

sen

siti

vity

anal

yses

use

the

FOA

Mva

lues

for

rele

van

tpar

amet

ers

We

expl

ore

the

sen

siti

vity

ofm

arin

eau

thig

enic

Mo

enri

chm

ents

todi

ssol

ved

seaw

ater

Mo

and

O2s

edim

enta

tion

rate

sor

gan

icm

atte

rra

infl

uxan

dpo

rew

ater

H2S

leve

lsov

era

wid

era

nge

ofpa

ram

eter

spac

ere

leva

ntt

oth

atco

nsi

dere

din

figu

re3



most extreme[Mo]





conclusions








REFERENCES












































































































































2 to MoS42 is




























33S 33S [(34S1000 1)0515 1] 13 1000 (2)






Fig

2C

ompi

lati

onof

Fesp

ecia

tion

data

from

mod

ern

sedi

men

ts

(A)

Non

-eux

inic

wat

erco

lum

ns

wit

h(C

anfi

eld

1989

Sc

hol

zan

dot

her

s20

14b

Rav

enan

dot

her

s20

16R

iedi

nge

ran

dot

her

s20

17)

and

wit

hou

t(C

anfi

eld

1989

Wijs

man

and

oth

ers

2001

Alle

ran

dot

her

s20

04G

oldb

erg

and

oth

ers

2012

Sch

olz

and

oth

ers

2014

bW

ehrm

ann

and

oth

ers

2014

Hen

kela

nd

oth

ers

2016

Rie

din

ger

and

oth

ers

2017

)po

rew

ater

sulfi

dein

the

hos

tsed

imen

ts(

B)

Eux

inic

(Rai

swel

lan

dC

anfi

eld

1998

Wijs

man

and

oth

ers

2001

Lyo

ns

and

oth

ers

2003

)lo

wox

ygen

(Rai

swel

lan

dC

anfi

eld

1998

Sch

olz

and

oth

ers

2014

bR

aven

and

oth

ers

2016

)an

dox

icw

ater

colu

mn

s(C

anfi

eld

1989

Rai

swel

lan

dC

anfi

eld

1998

Alle

ran

dot

her

s20

04G

oldb

erg

and

oth

ers

2012

Maumlr

zan

dot

her

s20

12Z

hu

and

oth

ers

2012

Aqu

ilin

aan

dot

her

s20

14S

chol

zan

dot

her

s20

14b

Weh

rman

nan

dot

her

s20

14P

eket

ian

dot

her

s20

15Z

hu

and

oth

ers

2015

Hen

kela

nd

oth

ers

2016

Rie

din

ger

and

oth

ers

2017

)L

owox

ygen

isde

fin

edas

15

M

O2

butl

acki

ng

dete

cted

sulfi

deN

otab

lyt

he

lsquohig

hly

reac

tive

rsquoFe

isde

term

ined

diff

eren

tly

betw

een

the

publ

icat

ion

sin

clud

ing

the

sequ

enti

alex

trac

tion

ofPo

ulto

nan

dC

anfi

eld

(200

5)i

tspr

edec

esso

rs(f

orex

ampl

eR

aisw

ella

nd

Can

fiel

d19

98A

ller

and

oth

ers

2004

)an

dot

her

mod

ifica

tion

s(f

orex

ampl

eR

aven

and

oth

ers

2016

)W

hen

avai

labl

eFe

py

FeH

Rin

clud

esir

onfr

omth

eac

idvo

lati

leS

extr

acti

onin

the

num

erat

orT

he

hor

izon

tall

ine

repr

esen

tsth

esu

gges

ted

boun

dary

for

oxic

wat

erco

lum

nco

ndi

tion

sfo

rm

oder

nse

dim

ents

03

8(C

anfi

eld

and

Rai

swel

l19

98)

Th

eve

rtic

allin

ere

pres

ents

the

Fep

yFe

HR

boun

dary

for

indi

cati

onof

sulfi

deac

cum

ulat

ion

of0

7w

hic

his

disc

usse

din

the

mai

nte

xtT

he

solid

bars

repr

esen

t1

ofth

ere

spec

tive

data


Fig

3B

oxan

dw

his

ker

plot

sco

mpa

rin

gse

dim

enta

ryM

oco

nce

ntr

atio

ns

from

(A

)O

xic

wat

erco

lum

nse

ttin

gsw

ith

(Mal

colm

198

5Pe

ders

en1

985

Mor

ford

and

oth

ers

2007

Po

ulso

nB

ruck

eran

dot

her

s20

09)

and

wit

hou

t(Z

hen

gan

dot

her

s20

00

Boumln

ing

and

oth

ers

2004

M

orfo

rdan

dot

her

s20

09

Poul

son

Bru

cker

and

oth

ers

2009

Sch

olz

and

oth

ers

2011

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dber

gan

dot

her

s20

12)

appr

ecia

ble

pore

wat

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lfide

con

cen

trat

ion

sIn

terv

alsw

her

eM

ois

asso

ciat

edw

ith

Mn

enri

chm

ents

(2

wt

M

nin

mos

tcas

es)

are

not

incl

uded

Not

eth

edi

ffer

ence

insc

ale

inpa

rtA

rela

tive

toB

and

C(

B)

Oxi

c(M

alco

lm1

985

Pede

rsen

198

5Sh

imm

ield

and

Pric

e19

86M

orfo

rdan

dE

mer

son

199

9Z

hen

gan

dot

her

s20

00B

oumlnin

gan

dot

her

s20

04S

undb

yan

dot

her

s20

04M

cMan

usan

dot

her

s20

06P

ouls

onan

dot

her

s20

06

Mor

ford

and

oth

ers

2007

Pou

lson

Bru

cker

and

oth

ers

2009

Mor

ford

and

oth

ers

2009

Sch

olz

and

oth

ers

2011

Gol

dber

gan

dot

her

s20

12)

and

low

oxyg

enw

ater

colu

mn

s(B

ron

gers

ma-

San

ders

and

oth

ers

1980

Cal

vert

and

Pric

e19

83M

orfo

rdan

dE

mer

son

199

9Z

hen

gan

dot

her

s20

00N

amer

offa

nd

oth

ers

2002

Boumln

ing

and

oth

ers

2004

McM

anus

and

oth

ers

2006

Pou

lson

and

oth

ers

2006

Pou

lson

Bru

cker

and

oth

ers

2009

Sch

olz

and

oth

ers

2011

)mdashde

fin

edas

15

M

O2

butl

acki

ng

diss

olve

dsu

lfide

(C

)L

owox

ygen

wat

erco

lum

nsi

tes

wit

h(Z

hen

gan

dot

her

s20

00B

oumlnin

gan

dot

her

s20

04P

ouls

onB

ruck

eran

dot

her

s20

09S

chol

zan

dot

her

s20

11)

and

wit

hou

t(Z

hen

gan

dot

her

s20

00

Nam

erof

fan

dot

her

s20

02

Sch

olz

and

oth

ers

2011

)ap

prec

iabl

esu

lfide

con

cen

trat

ion

sin

the

pore

wat

ers

Ala

ckof

appr

ecia

ble

sulfi

deis

defi

ned

bysu

lfide

mea

sure

dbu

t

100

M

su

lfide

mea

sure

dbu

tbe

low

dete

ctio

n

orsu

lfide

not

mea

sure

dbu

tw

ith

elev

ated

diss

olve

dFe

con

cen

trat

ion

s


Fig

4FO

AM

con

cen

trat

ion

profi

les

for

(A)

pore

wat

ersu

lfat

ean

dh

ydro

gen

sulfi

de(

B)

tota

lor

gan

icca

rbon

(TO

C)

and

(C)

wei

ght

perc

ent

sulf

urin

pyri

te

Als

oin

clud

edar

eis

otop

eco

mpo

siti

ons

of(D

)34S

(34S)

ofsu

lfat

ean

ddi

ssol

ved

sulfi

dean

d(E

)33S

(33S)

for

sulf

ate

and

diss

olve

dsu

lfide

In

part

Dd

ata

are

show

nfr

ombo

thth

eco

res

utili

zed

for

mea

sure

men

tin

AB

CE

ofth

isfi

gure

(201

0co

re)

and

prev

ious

lyun

publ

ish

edda

tafr

omco

reFO

AM

-1(A

ller

1980

a19

80b)

Sul

fur

isot

ope

data

are

show

nin

tabl

es1

and

2



TABLE 1




TABLE 2



2 2187 00324 2144 00418 2398 003612 3735 0113 -1895 014916 3600 0104 -1948 015520 3797 0122 -1780 015924 4216 0115 -1707 017928 4363 011732 4428 011936 4365 010240 4380 0116



TA

BL

E3

Res

ults

for

Fe

spec

iati

on

degr

eeof

pyri

tiza

tion

(DO

P)

bulk

sedi

men

tary

Fe

and

Al

conc

entr

atio

ns

and

tota

lor

gani

cca

rbon

(TO

C)

Dep

th

(cm

)Fe

asc

(wt

)Fe

dith

(wt

)Fe

mag

(wt

)Fe

py(w

t )

FeH

Cl(

wt

)

FeT

(wt

)A

l T(w

t )

FeH

RF

e TFe

pyF

e HR

FeTA

lD

OP

TO

C(w

t )

05

002

lt D

L

009

068

137

318

582

025

086

055

033

175

2ltD

L

011

006

065

114

344

661

024

079

052

036

185

40

060

130

050

311

183

166

430

180

550

490

211

206

003

010

006

036

133

296

567

019

065

052

022

122

80

010

040

020

351

053

136

450

140

840

480

251

3110

001

003

002

060

094

272

551

024

091

049

039

101

120

010

020

060

661

022

775

710

270

860

480

392

5014

lt D

L

lt D

L

001

074

116

303

603

025

098

050

039

121

160

010

020

010

650

943

116

190

220

940

500

410

7118

002

003

003

069

100

253

495

031

089

051

041

104

200

050

040

070

711

253

216

040

270

820

530

361

3222

lt D

L

lt D

L

006

093

092

332

667

030

094

050

050

142

240

01lt

DL

0

051

061

243

124

850

360

950

640

461

5226

lt D

L

lt D

L

007

083

112

369

738

024

093

050

043

165

28lt

DL

lt

DL

0

040

931

513

457

010

280

960

490

381

2430

lt D

L

lt D

L

002

086

097

303

569

028

099

053

047

145

320

040

020

080

681

213

176

120

260

830

520

361

4134

003

001

008

059

124

279

589

026

083

047

032

087

36lt

DL

lt

DL

0

030

701

103

196

090

230

960

520

391

5438

lt D

L

001

007

069

120

306

587

025

090

052

036

191

400

030

030

080

661

173

005

730

270

830

520

361

0042

002

001

006

055

114

328

647

019

087

051

033

147

440

020

010

070

711

133

045

700

270

880

530

391

6446

001

lt D

L

009

081

099

331

648

027

089

051

045

149

480

020

010

060

600

773

165

840

220

860

540

441

4250

lt D

L

lt D

L

002

085

084

284

522

031

097

054

050

127

DL

D

etec

tion

lim

it

The

data

are

pres

ente

din

figu

re5


Fig

5(A

)D

isso

lved

pore

wat

erFe

con

cen

trat

ion

s(B

)di

thio

nit

eFe

toto

tal

Fera

tios

(Fe d

ithF

e T)

(C)

degr

eeof

pyri

tiza

tion

(DO

P)a

nd

(D)

rati

osof

hig

hly

reac

tive

Feto

tota

lFe

con

cen

trat

ion

s(F

e HRF

e T)

tota

lFe

toA

lrat

ios

(Fe T

Al T

)an

dpy

riti

zed

Feov

erh

igh

lyre

acti

veFe

(Fe p

yFe

HR)

Th

eve

rtic

alba

rre

pres

ents

the

ran

geof

DO

Ppr

evio

usly

mea

sure

dat

FOA

Mfr

omC

anfi

eld

and

oth

ers

(199

2)



discussion






Fig

6Se

dim

enta

ry(A

)M

oco

nce

ntr

atio

ns

(B)

Mo

Alm

assr

atio

s(C

)po

rew

ater

Mo

con

cen

trat

ion

s(D

)se

dim

enta

ryM

nco

nce

ntr

atio

ns

and

(E)

pore

wat

erM

nco

nce

ntr

atio

ns

Hor

izon

tald

ash

edlin

esre

pres

entt

he

dept

hof

sign

ifica

nts

ulfi

deac

cum

ulat

ion

Sh

aded

area

srep

rese

ntM

oA

lave

rage

shal

eva

lues

from

Tur

ekia

nan

dW

edep

ohl(

1961

)




TABLE 4


Depth (cm)

Pore water Mo (nM)

Bulk Mo (ppm)

05 1574 11 2 1398 11 4 11 6 2965 10 8 10

10 799 10 12 12 14 1151 10 16 13 18 359 11 20 09 22 30 24 09 26 45 28 10 30 139 10 32 09 34 36 10 38 342 09 40 11 42 144 10 44 10 46 148 11 48 10 50 84 12




















[X]t

D2[X]

z2 [X]

z rxn (4)







korg[org][O2]






TABLE 5














Fig

7D

iage

net

icm

odel

resu

lts

Bas

elin

eva

lues

(red

dot)

are

para

met

ersd

eter

min

edfr

omth

eFO

AM

site

and

are

pres

ente

din

tabl

e5

Un

less

oth

erw

ise

indi

cate

dth

em

odel

sen

siti

vity

anal

yses

use

the

FOA

Mva

lues

for

rele

van

tpar

amet

ers

We

expl

ore

the

sen

siti

vity

ofm

arin

eau

thig

enic

Mo

enri

chm

ents

todi

ssol

ved

seaw

ater

Mo

and

O2s

edim

enta

tion

rate

sor

gan

icm

atte

rra

infl

uxan

dpo

rew

ater

H2S

leve

lsov

era

wid

era

nge

ofpa

ram

eter

spac

ere

leva

ntt

oth

atco

nsi

dere

din

figu

re3



most extreme[Mo]





conclusions








REFERENCES





























































































































































33S 33S [(34S1000 1)0515 1] 13 1000 (2)






Fig

2C

ompi

lati

onof

Fesp

ecia

tion

data

from

mod

ern

sedi

men

ts

(A)

Non

-eux

inic

wat

erco

lum

ns

wit

h(C

anfi

eld

1989

Sc

hol

zan

dot

her

s20

14b

Rav

enan

dot

her

s20

16R

iedi

nge

ran

dot

her

s20

17)

and

wit

hou

t(C

anfi

eld

1989

Wijs

man

and

oth

ers

2001

Alle

ran

dot

her

s20

04G

oldb

erg

and

oth

ers

2012

Sch

olz

and

oth

ers

2014

bW

ehrm

ann

and

oth

ers

2014

Hen

kela

nd

oth

ers

2016

Rie

din

ger

and

oth

ers

2017

)po

rew

ater

sulfi

dein

the

hos

tsed

imen

ts(

B)

Eux

inic

(Rai

swel

lan

dC

anfi

eld

1998

Wijs

man

and

oth

ers

2001

Lyo

ns

and

oth

ers

2003

)lo

wox

ygen

(Rai

swel

lan

dC

anfi

eld

1998

Sch

olz

and

oth

ers

2014

bR

aven

and

oth

ers

2016

)an

dox

icw

ater

colu

mn

s(C

anfi

eld

1989

Rai

swel

lan

dC

anfi

eld

1998

Alle

ran

dot

her

s20

04G

oldb

erg

and

oth

ers

2012

Maumlr

zan

dot

her

s20

12Z

hu

and

oth

ers

2012

Aqu

ilin

aan

dot

her

s20

14S

chol

zan

dot

her

s20

14b

Weh

rman

nan

dot

her

s20

14P

eket

ian

dot

her

s20

15Z

hu

and

oth

ers

2015

Hen

kela

nd

oth

ers

2016

Rie

din

ger

and

oth

ers

2017

)L

owox

ygen

isde

fin

edas

15

M

O2

butl

acki

ng

dete

cted

sulfi

deN

otab

lyt

he

lsquohig

hly

reac

tive

rsquoFe

isde

term

ined

diff

eren

tly

betw

een

the

publ

icat

ion

sin

clud

ing

the

sequ

enti

alex

trac

tion

ofPo

ulto

nan

dC

anfi

eld

(200

5)i

tspr

edec

esso

rs(f

orex

ampl

eR

aisw

ella

nd

Can

fiel

d19

98A

ller

and

oth

ers

2004

)an

dot

her

mod

ifica

tion

s(f

orex

ampl

eR

aven

and

oth

ers

2016

)W

hen

avai

labl

eFe

py

FeH

Rin

clud

esir

onfr

omth

eac

idvo

lati

leS

extr

acti

onin

the

num

erat

orT

he

hor

izon

tall

ine

repr

esen

tsth

esu

gges

ted

boun

dary

for

oxic

wat

erco

lum

nco

ndi

tion

sfo

rm

oder

nse

dim

ents

03

8(C

anfi

eld

and

Rai

swel

l19

98)

Th

eve

rtic

allin

ere

pres

ents

the

Fep

yFe

HR

boun

dary

for

indi

cati

onof

sulfi

deac

cum

ulat

ion

of0

7w

hic

his

disc

usse

din

the

mai

nte

xtT

he

solid

bars

repr

esen

t1

ofth

ere

spec

tive

data


Fig

3B

oxan

dw

his

ker

plot

sco

mpa

rin

gse

dim

enta

ryM

oco

nce

ntr

atio

ns

from

(A

)O

xic

wat

erco

lum

nse

ttin

gsw

ith

(Mal

colm

198

5Pe

ders

en1

985

Mor

ford

and

oth

ers

2007

Po

ulso

nB

ruck

eran

dot

her

s20

09)

and

wit

hou

t(Z

hen

gan

dot

her

s20

00

Boumln

ing

and

oth

ers

2004

M

orfo

rdan

dot

her

s20

09

Poul

son

Bru

cker

and

oth

ers

2009

Sch

olz

and

oth

ers

2011

Gol

dber

gan

dot

her

s20

12)

appr

ecia

ble

pore

wat

ersu

lfide

con

cen

trat

ion

sIn

terv

alsw

her

eM

ois

asso

ciat

edw

ith

Mn

enri

chm

ents

(2

wt

M

nin

mos

tcas

es)

are

not

incl

uded

Not

eth

edi

ffer

ence

insc

ale

inpa

rtA

rela

tive

toB

and

C(

B)

Oxi

c(M

alco

lm1

985

Pede

rsen

198

5Sh

imm

ield

and

Pric

e19

86M

orfo

rdan

dE

mer

son

199

9Z

hen

gan

dot

her

s20

00B

oumlnin

gan

dot

her

s20

04S

undb

yan

dot

her

s20

04M

cMan

usan

dot

her

s20

06P

ouls

onan

dot

her

s20

06

Mor

ford

and

oth

ers

2007

Pou

lson

Bru

cker

and

oth

ers

2009

Mor

ford

and

oth

ers

2009

Sch

olz

and

oth

ers

2011

Gol

dber

gan

dot

her

s20

12)

and

low

oxyg

enw

ater

colu

mn

s(B

ron

gers

ma-

San

ders

and

oth

ers

1980

Cal

vert

and

Pric

e19

83M

orfo

rdan

dE

mer

son

199

9Z

hen

gan

dot

her

s20

00N

amer

offa

nd

oth

ers

2002

Boumln

ing

and

oth

ers

2004

McM

anus

and

oth

ers

2006

Pou

lson

and

oth

ers

2006

Pou

lson

Bru

cker

and

oth

ers

2009

Sch

olz

and

oth

ers

2011

)mdashde

fin

edas

15

M

O2

butl

acki

ng

diss

olve

dsu

lfide

(C

)L

owox

ygen

wat

erco

lum

nsi

tes

wit

h(Z

hen

gan

dot

her

s20

00B

oumlnin

gan

dot

her

s20

04P

ouls

onB

ruck

eran

dot

her

s20

09S

chol

zan

dot

her

s20

11)

and

wit

hou

t(Z

hen

gan

dot

her

s20

00

Nam

erof

fan

dot

her

s20

02

Sch

olz

and

oth

ers

2011

)ap

prec

iabl

esu

lfide

con

cen

trat

ion

sin

the

pore

wat

ers

Ala

ckof

appr

ecia

ble

sulfi

deis

defi

ned

bysu

lfide

mea

sure

dbu

t

100

M

su

lfide

mea

sure

dbu

tbe

low

dete

ctio

n

orsu

lfide

not

mea

sure

dbu

tw

ith

elev

ated

diss

olve

dFe

con

cen

trat

ion

s


Fig

4FO

AM

con

cen

trat

ion

profi

les

for

(A)

pore

wat

ersu

lfat

ean

dh

ydro

gen

sulfi

de(

B)

tota

lor

gan

icca

rbon

(TO

C)

and

(C)

wei

ght

perc

ent

sulf

urin

pyri

te

Als

oin

clud

edar

eis

otop

eco

mpo

siti

ons

of(D

)34S

(34S)

ofsu

lfat

ean

ddi

ssol

ved

sulfi

dean

d(E

)33S

(33S)

for

sulf

ate

and

diss

olve

dsu

lfide

In

part

Dd

ata

are

show

nfr

ombo

thth

eco

res

utili

zed

for

mea

sure

men

tin

AB

CE

ofth

isfi

gure

(201

0co

re)

and

prev

ious

lyun

publ

ish

edda

tafr

omco

reFO

AM

-1(A

ller

1980

a19

80b)

Sul

fur

isot

ope

data

are

show

nin

tabl

es1

and

2



TABLE 1




TABLE 2



2 2187 00324 2144 00418 2398 003612 3735 0113 -1895 014916 3600 0104 -1948 015520 3797 0122 -1780 015924 4216 0115 -1707 017928 4363 011732 4428 011936 4365 010240 4380 0116



TA

BL

E3

Res

ults

for

Fe

spec

iati

on

degr

eeof

pyri

tiza

tion

(DO

P)

bulk

sedi

men

tary

Fe

and

Al

conc

entr

atio

ns

and

tota

lor

gani

cca

rbon

(TO

C)

Dep

th

(cm

)Fe

asc

(wt

)Fe

dith

(wt

)Fe

mag

(wt

)Fe

py(w

t )

FeH

Cl(

wt

)

FeT

(wt

)A

l T(w

t )

FeH

RF

e TFe

pyF

e HR

FeTA

lD

OP

TO

C(w

t )

05

002

lt D

L

009

068

137

318

582

025

086

055

033

175

2ltD

L

011

006

065

114

344

661

024

079

052

036

185

40

060

130

050

311

183

166

430

180

550

490

211

206

003

010

006

036

133

296

567

019

065

052

022

122

80

010

040

020

351

053

136

450

140

840

480

251

3110

001

003

002

060

094

272

551

024

091

049

039

101

120

010

020

060

661

022

775

710

270

860

480

392

5014

lt D

L

lt D

L

001

074

116

303

603

025

098

050

039

121

160

010

020

010

650

943

116

190

220

940

500

410

7118

002

003

003

069

100

253

495

031

089

051

041

104

200

050

040

070

711

253

216

040

270

820

530

361

3222

lt D

L

lt D

L

006

093

092

332

667

030

094

050

050

142

240

01lt

DL

0

051

061

243

124

850

360

950

640

461

5226

lt D

L

lt D

L

007

083

112

369

738

024

093

050

043

165

28lt

DL

lt

DL

0

040

931

513

457

010

280

960

490

381

2430

lt D

L

lt D

L

002

086

097

303

569

028

099

053

047

145

320

040

020

080

681

213

176

120

260

830

520

361

4134

003

001

008

059

124

279

589

026

083

047

032

087

36lt

DL

lt

DL

0

030

701

103

196

090

230

960

520

391

5438

lt D

L

001

007

069

120

306

587

025

090

052

036

191

400

030

030

080

661

173

005

730

270

830

520

361

0042

002

001

006

055

114

328

647

019

087

051

033

147

440

020

010

070

711

133

045

700

270

880

530

391

6446

001

lt D

L

009

081

099

331

648

027

089

051

045

149

480

020

010

060

600

773

165

840

220

860

540

441

4250

lt D

L

lt D

L

002

085

084

284

522

031

097

054

050

127

DL

D

etec

tion

lim

it

The

data

are

pres

ente

din

figu

re5


Fig

5(A

)D

isso

lved

pore

wat

erFe

con

cen

trat

ion

s(B

)di

thio

nit

eFe

toto

tal

Fera

tios

(Fe d

ithF

e T)

(C)

degr

eeof

pyri

tiza

tion

(DO

P)a

nd

(D)

rati

osof

hig

hly

reac

tive

Feto

tota

lFe

con

cen

trat

ion

s(F

e HRF

e T)

tota

lFe

toA

lrat

ios

(Fe T

Al T

)an

dpy

riti

zed

Feov

erh

igh

lyre

acti

veFe

(Fe p

yFe

HR)

Th

eve

rtic

alba

rre

pres

ents

the

ran

geof

DO

Ppr

evio

usly

mea

sure

dat

FOA

Mfr

omC

anfi

eld

and

oth

ers

(199

2)



discussion






Fig

6Se

dim

enta

ry(A

)M

oco

nce

ntr

atio

ns

(B)

Mo

Alm

assr

atio

s(C

)po

rew

ater

Mo

con

cen

trat

ion

s(D

)se

dim

enta

ryM

nco

nce

ntr

atio

ns

and

(E)

pore

wat

erM

nco

nce

ntr

atio

ns

Hor

izon

tald

ash

edlin

esre

pres

entt

he

dept

hof

sign

ifica

nts

ulfi

deac

cum

ulat

ion

Sh

aded

area

srep

rese

ntM

oA

lave

rage

shal

eva

lues

from

Tur

ekia

nan

dW

edep

ohl(

1961

)




TABLE 4


Depth (cm)

Pore water Mo (nM)

Bulk Mo (ppm)

05 1574 11 2 1398 11 4 11 6 2965 10 8 10

10 799 10 12 12 14 1151 10 16 13 18 359 11 20 09 22 30 24 09 26 45 28 10 30 139 10 32 09 34 36 10 38 342 09 40 11 42 144 10 44 10 46 148 11 48 10 50 84 12




















[X]t

D2[X]

z2 [X]

z rxn (4)







korg[org][O2]






TABLE 5














Fig

7D

iage

net

icm

odel

resu

lts

Bas

elin

eva

lues

(red

dot)

are

para

met

ersd

eter

min

edfr

omth

eFO

AM

site

and

are

pres

ente

din

tabl

e5

Un

less

oth

erw

ise

indi

cate

dth

em

odel

sen

siti

vity

anal

yses

use

the

FOA

Mva

lues

for

rele

van

tpar

amet

ers

We

expl

ore

the

sen

siti

vity

ofm

arin

eau

thig

enic

Mo

enri

chm

ents

todi

ssol

ved

seaw

ater

Mo

and

O2s

edim

enta

tion

rate

sor

gan

icm

atte

rra

infl

uxan

dpo

rew

ater

H2S

leve

lsov

era

wid

era

nge

ofpa

ram

eter

spac

ere

leva

ntt

oth

atco

nsi

dere

din

figu

re3



most extreme[Mo]





conclusions








REFERENCES
























































































































































33S 33S [(34S1000 1)0515 1] 13 1000 (2)






Fig

2C

ompi

lati

onof

Fesp

ecia

tion

data

from

mod

ern

sedi

men

ts

(A)

Non

-eux

inic

wat

erco

lum

ns

wit

h(C

anfi

eld

1989

Sc

hol

zan

dot

her

s20

14b

Rav

enan

dot

her

s20

16R

iedi

nge

ran

dot

her

s20

17)

and

wit

hou

t(C

anfi

eld

1989

Wijs

man

and

oth

ers

2001

Alle

ran

dot

her

s20

04G

oldb

erg

and

oth

ers

2012

Sch

olz

and

oth

ers

2014

bW

ehrm

ann

and

oth

ers

2014

Hen

kela

nd

oth

ers

2016

Rie

din

ger

and

oth

ers

2017

)po

rew

ater

sulfi

dein

the

hos

tsed

imen

ts(

B)

Eux

inic

(Rai

swel

lan

dC

anfi

eld

1998

Wijs

man

and

oth

ers

2001

Lyo

ns

and

oth

ers

2003

)lo

wox

ygen

(Rai

swel

lan

dC

anfi

eld

1998

Sch

olz

and

oth

ers

2014

bR

aven

and

oth

ers

2016

)an

dox

icw

ater

colu

mn

s(C

anfi

eld

1989

Rai

swel

lan

dC

anfi

eld

1998

Alle

ran

dot

her

s20

04G

oldb

erg

and

oth

ers

2012

Maumlr

zan

dot

her

s20

12Z

hu

and

oth

ers

2012

Aqu

ilin

aan

dot

her

s20

14S

chol

zan

dot

her

s20

14b

Weh

rman

nan

dot

her

s20

14P

eket

ian

dot

her

s20

15Z

hu

and

oth

ers

2015

Hen

kela

nd

oth

ers

2016

Rie

din

ger

and

oth

ers

2017

)L

owox

ygen

isde

fin

edas

15

M

O2

butl

acki

ng

dete

cted

sulfi

deN

otab

lyt

he

lsquohig

hly

reac

tive

rsquoFe

isde

term

ined

diff

eren

tly

betw

een

the

publ

icat

ion

sin

clud

ing

the

sequ

enti

alex

trac

tion

ofPo

ulto

nan

dC

anfi

eld

(200

5)i

tspr

edec

esso

rs(f

orex

ampl

eR

aisw

ella

nd

Can

fiel

d19

98A

ller

and

oth

ers

2004

)an

dot

her

mod

ifica

tion

s(f

orex

ampl

eR

aven

and

oth

ers

2016

)W

hen

avai

labl

eFe

py

FeH

Rin

clud

esir

onfr

omth

eac

idvo

lati

leS

extr

acti

onin

the

num

erat

orT

he

hor

izon

tall

ine

repr

esen

tsth

esu

gges

ted

boun

dary

for

oxic

wat

erco

lum

nco

ndi

tion

sfo

rm

oder

nse

dim

ents

03

8(C

anfi

eld

and

Rai

swel

l19

98)

Th

eve

rtic

allin

ere

pres

ents

the

Fep

yFe

HR

boun

dary

for

indi

cati

onof

sulfi

deac

cum

ulat

ion

of0

7w

hic

his

disc

usse

din

the

mai

nte

xtT

he

solid

bars

repr

esen

t1

ofth

ere

spec

tive

data


Fig

3B

oxan

dw

his

ker

plot

sco

mpa

rin

gse

dim

enta

ryM

oco

nce

ntr

atio

ns

from

(A

)O

xic

wat

erco

lum

nse

ttin

gsw

ith

(Mal

colm

198

5Pe

ders

en1

985

Mor

ford

and

oth

ers

2007

Po

ulso

nB

ruck

eran

dot

her

s20

09)

and

wit

hou

t(Z

hen

gan

dot

her

s20

00

Boumln

ing

and

oth

ers

2004

M

orfo

rdan

dot

her

s20

09

Poul

son

Bru

cker

and

oth

ers

2009

Sch

olz

and

oth

ers

2011

Gol

dber

gan

dot

her

s20

12)

appr

ecia

ble

pore

wat

ersu

lfide

con

cen

trat

ion

sIn

terv

alsw

her

eM

ois

asso

ciat

edw

ith

Mn

enri

chm

ents

(2

wt

M

nin

mos

tcas

es)

are

not

incl

uded

Not

eth

edi

ffer

ence

insc

ale

inpa

rtA

rela

tive

toB

and

C(

B)

Oxi

c(M

alco

lm1

985

Pede

rsen

198

5Sh

imm

ield

and

Pric

e19

86M

orfo

rdan

dE

mer

son

199

9Z

hen

gan

dot

her

s20

00B

oumlnin

gan

dot

her

s20

04S

undb

yan

dot

her

s20

04M

cMan

usan

dot

her

s20

06P

ouls

onan

dot

her

s20

06

Mor

ford

and

oth

ers

2007

Pou

lson

Bru

cker

and

oth

ers

2009

Mor

ford

and

oth

ers

2009

Sch

olz

and

oth

ers

2011

Gol

dber

gan

dot

her

s20

12)

and

low

oxyg

enw

ater

colu

mn

s(B

ron

gers

ma-

San

ders

and

oth

ers

1980

Cal

vert

and

Pric

e19

83M

orfo

rdan

dE

mer

son

199

9Z

hen

gan

dot

her

s20

00N

amer

offa

nd

oth

ers

2002

Boumln

ing

and

oth

ers

2004

McM

anus

and

oth

ers

2006

Pou

lson

and

oth

ers

2006

Pou

lson

Bru

cker

and

oth

ers

2009

Sch

olz

and

oth

ers

2011

)mdashde

fin

edas

15

M

O2

butl

acki

ng

diss

olve

dsu

lfide

(C

)L

owox

ygen

wat

erco

lum

nsi

tes

wit

h(Z

hen

gan

dot

her

s20

00B

oumlnin

gan

dot

her

s20

04P

ouls

onB

ruck

eran

dot

her

s20

09S

chol

zan

dot

her

s20

11)

and

wit

hou

t(Z

hen

gan

dot

her

s20

00

Nam

erof

fan

dot

her

s20

02

Sch

olz

and

oth

ers

2011

)ap

prec

iabl

esu

lfide

con

cen

trat

ion

sin

the

pore

wat

ers

Ala

ckof

appr

ecia

ble

sulfi

deis

defi

ned

bysu

lfide

mea

sure

dbu

t

100

M

su

lfide

mea

sure

dbu

tbe

low

dete

ctio

n

orsu

lfide

not

mea

sure

dbu

tw

ith

elev

ated

diss

olve

dFe

con

cen

trat

ion

s


Fig

4FO

AM

con

cen

trat

ion

profi

les

for

(A)

pore

wat

ersu

lfat

ean

dh

ydro

gen

sulfi

de(

B)

tota

lor

gan

icca

rbon

(TO

C)

and

(C)

wei

ght

perc

ent

sulf

urin

pyri

te

Als

oin

clud

edar

eis

otop

eco

mpo

siti

ons

of(D

)34S

(34S)

ofsu

lfat

ean

ddi

ssol

ved

sulfi

dean

d(E

)33S

(33S)

for

sulf

ate

and

diss

olve

dsu

lfide

In

part

Dd

ata

are

show

nfr

ombo

thth

eco

res

utili

zed

for

mea

sure

men

tin

AB

CE

ofth

isfi

gure

(201

0co

re)

and

prev

ious

lyun

publ

ish

edda

tafr

omco

reFO

AM

-1(A

ller

1980

a19

80b)

Sul

fur

isot

ope

data

are

show

nin

tabl

es1

and

2



TABLE 1




TABLE 2



2 2187 00324 2144 00418 2398 003612 3735 0113 -1895 014916 3600 0104 -1948 015520 3797 0122 -1780 015924 4216 0115 -1707 017928 4363 011732 4428 011936 4365 010240 4380 0116



TA

BL

E3

Res

ults

for

Fe

spec

iati

on

degr

eeof

pyri

tiza

tion

(DO

P)

bulk

sedi

men

tary

Fe

and

Al

conc

entr

atio

ns

and

tota

lor

gani

cca

rbon

(TO

C)

Dep

th

(cm

)Fe

asc

(wt

)Fe

dith

(wt

)Fe

mag

(wt

)Fe

py(w

t )

FeH

Cl(

wt

)

FeT

(wt

)A

l T(w

t )

FeH

RF

e TFe

pyF

e HR

FeTA

lD

OP

TO

C(w

t )

05

002

lt D

L

009

068

137

318

582

025

086

055

033

175

2ltD

L

011

006

065

114

344

661

024

079

052

036

185

40

060

130

050

311

183

166

430

180

550

490

211

206

003

010

006

036

133

296

567

019

065

052

022

122

80

010

040

020

351

053

136

450

140

840

480

251

3110

001

003

002

060

094

272

551

024

091

049

039

101

120

010

020

060

661

022

775

710

270

860

480

392

5014

lt D

L

lt D

L

001

074

116

303

603

025

098

050

039

121

160

010

020

010

650

943

116

190

220

940

500

410

7118

002

003

003

069

100

253

495

031

089

051

041

104

200

050

040

070

711

253

216

040

270

820

530

361

3222

lt D

L

lt D

L

006

093

092

332

667

030

094

050

050

142

240

01lt

DL

0

051

061

243

124

850

360

950

640

461

5226

lt D

L

lt D

L

007

083

112

369

738

024

093

050

043

165

28lt

DL

lt

DL

0

040

931

513

457

010

280

960

490

381

2430

lt D

L

lt D

L

002

086

097

303

569

028

099

053

047

145

320

040

020

080

681

213

176

120

260

830

520

361

4134

003

001

008

059

124

279

589

026

083

047

032

087

36lt

DL

lt

DL

0

030

701

103

196

090

230

960

520

391

5438

lt D

L

001

007

069

120

306

587

025

090

052

036

191

400

030

030

080

661

173

005

730

270

830

520

361

0042

002

001

006

055

114

328

647

019

087

051

033

147

440

020

010

070

711

133

045

700

270

880

530

391

6446

001

lt D

L

009

081

099

331

648

027

089

051

045

149

480

020

010

060

600

773

165

840

220

860

540

441

4250

lt D

L

lt D

L

002

085

084

284

522

031

097

054

050

127

DL

D

etec

tion

lim

it

The

data

are

pres

ente

din

figu

re5


Fig

5(A

)D

isso

lved

pore

wat

erFe

con

cen

trat

ion

s(B

)di

thio

nit

eFe

toto

tal

Fera

tios

(Fe d

ithF

e T)

(C)

degr

eeof

pyri

tiza

tion

(DO

P)a

nd

(D)

rati

osof

hig

hly

reac

tive

Feto

tota

lFe

con

cen

trat

ion

s(F

e HRF

e T)

tota

lFe

toA

lrat

ios

(Fe T

Al T

)an

dpy

riti

zed

Feov

erh

igh

lyre

acti

veFe

(Fe p

yFe

HR)

Th

eve

rtic

alba

rre

pres

ents

the

ran

geof

DO

Ppr

evio

usly

mea

sure

dat

FOA

Mfr

omC

anfi

eld

and

oth

ers

(199

2)



discussion






Fig

6Se

dim

enta

ry(A

)M

oco

nce

ntr

atio

ns

(B)

Mo

Alm

assr

atio

s(C

)po

rew

ater

Mo

con

cen

trat

ion

s(D

)se

dim

enta

ryM

nco

nce

ntr

atio

ns

and

(E)

pore

wat

erM

nco

nce

ntr

atio

ns

Hor

izon

tald

ash

edlin

esre

pres

entt

he

dept

hof

sign

ifica

nts

ulfi

deac

cum

ulat

ion

Sh

aded

area

srep

rese

ntM

oA

lave

rage

shal

eva

lues

from

Tur

ekia

nan

dW

edep

ohl(

1961

)




TABLE 4


Depth (cm)

Pore water Mo (nM)

Bulk Mo (ppm)

05 1574 11 2 1398 11 4 11 6 2965 10 8 10

10 799 10 12 12 14 1151 10 16 13 18 359 11 20 09 22 30 24 09 26 45 28 10 30 139 10 32 09 34 36 10 38 342 09 40 11 42 144 10 44 10 46 148 11 48 10 50 84 12




















[X]t

D2[X]

z2 [X]

z rxn (4)







korg[org][O2]






TABLE 5














Fig

7D

iage

net

icm

odel

resu

lts

Bas

elin

eva

lues

(red

dot)

are

para

met

ersd

eter

min

edfr

omth

eFO

AM

site

and

are

pres

ente

din

tabl

e5

Un

less

oth

erw

ise

indi

cate

dth

em

odel

sen

siti

vity

anal

yses

use

the

FOA

Mva

lues

for

rele

van

tpar

amet

ers

We

expl

ore

the

sen

siti

vity

ofm

arin

eau

thig

enic

Mo

enri

chm

ents

todi

ssol

ved

seaw

ater

Mo

and

O2s

edim

enta

tion

rate

sor

gan

icm

atte

rra

infl

uxan

dpo

rew

ater

H2S

leve

lsov

era

wid

era

nge

ofpa

ram

eter

spac

ere

leva

ntt

oth

atco

nsi

dere

din

figu

re3



most extreme[Mo]





conclusions








REFERENCES
















































































































































33S 33S [(34S1000 1)0515 1] 13 1000 (2)






Fig

2C

ompi

lati

onof

Fesp

ecia

tion

data

from

mod

ern

sedi

men

ts

(A)

Non

-eux

inic

wat

erco

lum

ns

wit

h(C

anfi

eld

1989

Sc

hol

zan

dot

her

s20

14b

Rav

enan

dot

her

s20

16R

iedi

nge

ran

dot

her

s20

17)

and

wit

hou

t(C

anfi

eld

1989

Wijs

man

and

oth

ers

2001

Alle

ran

dot

her

s20

04G

oldb

erg

and

oth

ers

2012

Sch

olz

and

oth

ers

2014

bW

ehrm

ann

and

oth

ers

2014

Hen

kela

nd

oth

ers

2016

Rie

din

ger

and

oth

ers

2017

)po

rew

ater

sulfi

dein

the

hos

tsed

imen

ts(

B)

Eux

inic

(Rai

swel

lan

dC

anfi

eld

1998

Wijs

man

and

oth

ers

2001

Lyo

ns

and

oth

ers

2003

)lo

wox

ygen

(Rai

swel

lan

dC

anfi

eld

1998

Sch

olz

and

oth

ers

2014

bR

aven

and

oth

ers

2016

)an

dox

icw

ater

colu

mn

s(C

anfi

eld

1989

Rai

swel

lan

dC

anfi

eld

1998

Alle

ran

dot

her

s20

04G

oldb

erg

and

oth

ers

2012

Maumlr

zan

dot

her

s20

12Z

hu

and

oth

ers

2012

Aqu

ilin

aan

dot

her

s20

14S

chol

zan

dot

her

s20

14b

Weh

rman

nan

dot

her

s20

14P

eket

ian

dot

her

s20

15Z

hu

and

oth

ers

2015

Hen

kela

nd

oth

ers

2016

Rie

din

ger

and

oth

ers

2017

)L

owox

ygen

isde

fin

edas

15

M

O2

butl

acki

ng

dete

cted

sulfi

deN

otab

lyt

he

lsquohig

hly

reac

tive

rsquoFe

isde

term

ined

diff

eren

tly

betw

een

the

publ

icat

ion

sin

clud

ing

the

sequ

enti

alex

trac

tion

ofPo

ulto

nan

dC

anfi

eld

(200

5)i

tspr

edec

esso

rs(f

orex

ampl

eR

aisw

ella

nd

Can

fiel

d19

98A

ller

and

oth

ers

2004

)an

dot

her

mod

ifica

tion

s(f

orex

ampl

eR

aven

and

oth

ers

2016

)W

hen

avai

labl

eFe

py

FeH

Rin

clud

esir

onfr

omth

eac

idvo

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leS

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acti

onin

the

num

erat

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he

hor

izon

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ine

repr

esen

tsth

esu

gges

ted

boun

dary

for

oxic

wat

erco

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nco

ndi

tion

sfo

rm

oder

nse

dim

ents

03

8(C

anfi

eld

and

Rai

swel

l19

98)

Th

eve

rtic

allin

ere

pres

ents

the

Fep

yFe

HR

boun

dary

for

indi

cati

onof

sulfi

deac

cum

ulat

ion

of0

7w

hic

his

disc

usse

din

the

mai

nte

xtT

he

solid

bars

repr

esen

t1

ofth

ere

spec

tive

data


Fig

3B

oxan

dw

his

ker

plot

sco

mpa

rin

gse

dim

enta

ryM

oco

nce

ntr

atio

ns

from

(A

)O

xic

wat

erco

lum

nse

ttin

gsw

ith

(Mal

colm

198

5Pe

ders

en1

985

Mor

ford

and

oth

ers

2007

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ulso

nB

ruck

eran

dot

her

s20

09)

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wit

hou

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dot

her

s20

00

Boumln

ing

and

oth

ers

2004

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orfo

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her

s20

09

Poul

son

Bru

cker

and

oth

ers

2009

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olz

and

oth

ers

2011

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dber

gan

dot

her

s20

12)

appr

ecia

ble

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con

cen

trat

ion

sIn

terv

alsw

her

eM

ois

asso

ciat

edw

ith

Mn

enri

chm

ents

(2

wt

M

nin

mos

tcas

es)

are

not

incl

uded

Not

eth

edi

ffer

ence

insc

ale

inpa

rtA

rela

tive

toB

and

C(

B)

Oxi

c(M

alco

lm1

985

Pede

rsen

198

5Sh

imm

ield

and

Pric

e19

86M

orfo

rdan

dE

mer

son

199

9Z

hen

gan

dot

her

s20

00B

oumlnin

gan

dot

her

s20

04S

undb

yan

dot

her

s20

04M

cMan

usan

dot

her

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06P

ouls

onan

dot

her

s20

06

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ford

and

oth

ers

2007

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lson

Bru

cker

and

oth

ers

2009

Mor

ford

and

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ers

2009

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olz

and

oth

ers

2011

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dber

gan

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her

s20

12)

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ater

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mn

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ron

gers

ma-

San

ders

and

oth

ers

1980

Cal

vert

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e19

83M

orfo

rdan

dE

mer

son

199

9Z

hen

gan

dot

her

s20

00N

amer

offa

nd

oth

ers

2002

Boumln

ing

and

oth

ers

2004

McM

anus

and

oth

ers

2006

Pou

lson

and

oth

ers

2006

Pou

lson

Bru

cker

and

oth

ers

2009

Sch

olz

and

oth

ers

2011

)mdashde

fin

edas

15

M

O2

butl

acki

ng

diss

olve

dsu

lfide

(C

)L

owox

ygen

wat

erco

lum

nsi

tes

wit

h(Z

hen

gan

dot

her

s20

00B

oumlnin

gan

dot

her

s20

04P

ouls

onB

ruck

eran

dot

her

s20

09S

chol

zan

dot

her

s20

11)

and

wit

hou

t(Z

hen

gan

dot

her

s20

00

Nam

erof

fan

dot

her

s20

02

Sch

olz

and

oth

ers

2011

)ap

prec

iabl

esu

lfide

con

cen

trat

ion

sin

the

pore

wat

ers

Ala

ckof

appr

ecia

ble

sulfi

deis

defi

ned

bysu

lfide

mea

sure

dbu

t

100

M

su

lfide

mea

sure

dbu

tbe

low

dete

ctio

n

orsu

lfide

not

mea

sure

dbu

tw

ith

elev

ated

diss

olve

dFe

con

cen

trat

ion

s


Fig

4FO

AM

con

cen

trat

ion

profi

les

for

(A)

pore

wat

ersu

lfat

ean

dh

ydro

gen

sulfi

de(

B)

tota

lor

gan

icca

rbon

(TO

C)

and

(C)

wei

ght

perc

ent

sulf

urin

pyri

te

Als

oin

clud

edar

eis

otop

eco

mpo

siti

ons

of(D

)34S

(34S)

ofsu

lfat

ean

ddi

ssol

ved

sulfi

dean

d(E

)33S

(33S)

for

sulf

ate

and

diss

olve

dsu

lfide

In

part

Dd

ata

are

show

nfr

ombo

thth

eco

res

utili

zed

for

mea

sure

men

tin

AB

CE

ofth

isfi

gure

(201

0co

re)

and

prev

ious

lyun

publ

ish

edda

tafr

omco

reFO

AM

-1(A

ller

1980

a19

80b)

Sul

fur

isot

ope

data

are

show

nin

tabl

es1

and

2



TABLE 1




TABLE 2



2 2187 00324 2144 00418 2398 003612 3735 0113 -1895 014916 3600 0104 -1948 015520 3797 0122 -1780 015924 4216 0115 -1707 017928 4363 011732 4428 011936 4365 010240 4380 0116



TA

BL

E3

Res

ults

for

Fe

spec

iati

on

degr

eeof

pyri

tiza

tion

(DO

P)

bulk

sedi

men

tary

Fe

and

Al

conc

entr

atio

ns

and

tota

lor

gani

cca

rbon

(TO

C)

Dep

th

(cm

)Fe

asc

(wt

)Fe

dith

(wt

)Fe

mag

(wt

)Fe

py(w

t )

FeH

Cl(

wt

)

FeT

(wt

)A

l T(w

t )

FeH

RF

e TFe

pyF

e HR

FeTA

lD

OP

TO

C(w

t )

05

002

lt D

L

009

068

137

318

582

025

086

055

033

175

2ltD

L

011

006

065

114

344

661

024

079

052

036

185

40

060

130

050

311

183

166

430

180

550

490

211

206

003

010

006

036

133

296

567

019

065

052

022

122

80

010

040

020

351

053

136

450

140

840

480

251

3110

001

003

002

060

094

272

551

024

091

049

039

101

120

010

020

060

661

022

775

710

270

860

480

392

5014

lt D

L

lt D

L

001

074

116

303

603

025

098

050

039

121

160

010

020

010

650

943

116

190

220

940

500

410

7118

002

003

003

069

100

253

495

031

089

051

041

104

200

050

040

070

711

253

216

040

270

820

530

361

3222

lt D

L

lt D

L

006

093

092

332

667

030

094

050

050

142

240

01lt

DL

0

051

061

243

124

850

360

950

640

461

5226

lt D

L

lt D

L

007

083

112

369

738

024

093

050

043

165

28lt

DL

lt

DL

0

040

931

513

457

010

280

960

490

381

2430

lt D

L

lt D

L

002

086

097

303

569

028

099

053

047

145

320

040

020

080

681

213

176

120

260

830

520

361

4134

003

001

008

059

124

279

589

026

083

047

032

087

36lt

DL

lt

DL

0

030

701

103

196

090

230

960

520

391

5438

lt D

L

001

007

069

120

306

587

025

090

052

036

191

400

030

030

080

661

173

005

730

270

830

520

361

0042

002

001

006

055

114

328

647

019

087

051

033

147

440

020

010

070

711

133

045

700

270

880

530

391

6446

001

lt D

L

009

081

099

331

648

027

089

051

045

149

480

020

010

060

600

773

165

840

220

860

540

441

4250

lt D

L

lt D

L

002

085

084

284

522

031

097

054

050

127

DL

D

etec

tion

lim

it

The

data

are

pres

ente

din

figu

re5


Fig

5(A

)D

isso

lved

pore

wat

erFe

con

cen

trat

ion

s(B

)di

thio

nit

eFe

toto

tal

Fera

tios

(Fe d

ithF

e T)

(C)

degr

eeof

pyri

tiza

tion

(DO

P)a

nd

(D)

rati

osof

hig

hly

reac

tive

Feto

tota

lFe

con

cen

trat

ion

s(F

e HRF

e T)

tota

lFe

toA

lrat

ios

(Fe T

Al T

)an

dpy

riti

zed

Feov

erh

igh

lyre

acti

veFe

(Fe p

yFe

HR)

Th

eve

rtic

alba

rre

pres

ents

the

ran

geof

DO

Ppr

evio

usly

mea

sure

dat

FOA

Mfr

omC

anfi

eld

and

oth

ers

(199

2)



discussion






Fig

6Se

dim

enta

ry(A

)M

oco

nce

ntr

atio

ns

(B)

Mo

Alm

assr

atio

s(C

)po

rew

ater

Mo

con

cen

trat

ion

s(D

)se

dim

enta

ryM

nco

nce

ntr

atio

ns

and

(E)

pore

wat

erM

nco

nce

ntr

atio

ns

Hor

izon

tald

ash

edlin

esre

pres

entt

he

dept

hof

sign

ifica

nts

ulfi

deac

cum

ulat

ion

Sh

aded

area

srep

rese

ntM

oA

lave

rage

shal

eva

lues

from

Tur

ekia

nan

dW

edep

ohl(

1961

)




TABLE 4


Depth (cm)

Pore water Mo (nM)

Bulk Mo (ppm)

05 1574 11 2 1398 11 4 11 6 2965 10 8 10

10 799 10 12 12 14 1151 10 16 13 18 359 11 20 09 22 30 24 09 26 45 28 10 30 139 10 32 09 34 36 10 38 342 09 40 11 42 144 10 44 10 46 148 11 48 10 50 84 12




















[X]t

D2[X]

z2 [X]

z rxn (4)







korg[org][O2]






TABLE 5














Fig

7D

iage

net

icm

odel

resu

lts

Bas

elin

eva

lues

(red

dot)

are

para

met

ersd

eter

min

edfr

omth

eFO

AM

site

and

are

pres

ente

din

tabl

e5

Un

less

oth

erw

ise

indi

cate

dth

em

odel

sen

siti

vity

anal

yses

use

the

FOA

Mva

lues

for

rele

van

tpar

amet

ers

We

expl

ore

the

sen

siti

vity

ofm

arin

eau

thig

enic

Mo

enri

chm

ents

todi

ssol

ved

seaw

ater

Mo

and

O2s

edim

enta

tion

rate

sor

gan

icm

atte

rra

infl

uxan

dpo

rew

ater

H2S

leve

lsov

era

wid

era

nge

ofpa

ram

eter

spac

ere

leva

ntt

oth

atco

nsi

dere

din

figu

re3



most extreme[Mo]





conclusions








REFERENCES







































































































































33S 33S [(34S1000 1)0515 1] 13 1000 (2)






Fig

2C

ompi

lati

onof

Fesp

ecia

tion

data

from

mod

ern

sedi

men

ts

(A)

Non

-eux

inic

wat

erco

lum

ns

wit

h(C

anfi

eld

1989

Sc

hol

zan

dot

her

s20

14b

Rav

enan

dot

her

s20

16R

iedi

nge

ran

dot

her

s20

17)

and

wit

hou

t(C

anfi

eld

1989

Wijs

man

and

oth

ers

2001

Alle

ran

dot

her

s20

04G

oldb

erg

and

oth

ers

2012

Sch

olz

and

oth

ers

2014

bW

ehrm

ann

and

oth

ers

2014

Hen

kela

nd

oth

ers

2016

Rie

din

ger

and

oth

ers

2017

)po

rew

ater

sulfi

dein

the

hos

tsed

imen

ts(

B)

Eux

inic

(Rai

swel

lan

dC

anfi

eld

1998

Wijs

man

and

oth

ers

2001

Lyo

ns

and

oth

ers

2003

)lo

wox

ygen

(Rai

swel

lan

dC

anfi

eld

1998

Sch

olz

and

oth

ers

2014

bR

aven

and

oth

ers

2016

)an

dox

icw

ater

colu

mn

s(C

anfi

eld

1989

Rai

swel

lan

dC

anfi

eld

1998

Alle

ran

dot

her

s20

04G

oldb

erg

and

oth

ers

2012

Maumlr

zan

dot

her

s20

12Z

hu

and

oth

ers

2012

Aqu

ilin

aan

dot

her

s20

14S

chol

zan

dot

her

s20

14b

Weh

rman

nan

dot

her

s20

14P

eket

ian

dot

her

s20

15Z

hu

and

oth

ers

2015

Hen

kela

nd

oth

ers

2016

Rie

din

ger

and

oth

ers

2017

)L

owox

ygen

isde

fin

edas

15

M

O2

butl

acki

ng

dete

cted

sulfi

deN

otab

lyt

he

lsquohig

hly

reac

tive

rsquoFe

isde

term

ined

diff

eren

tly

betw

een

the

publ

icat

ion

sin

clud

ing

the

sequ

enti

alex

trac

tion

ofPo

ulto

nan

dC

anfi

eld

(200

5)i

tspr

edec

esso

rs(f

orex

ampl

eR

aisw

ella

nd

Can

fiel

d19

98A

ller

and

oth

ers

2004

)an

dot

her

mod

ifica

tion

s(f

orex

ampl

eR

aven

and

oth

ers

2016

)W

hen

avai

labl

eFe

py

FeH

Rin

clud

esir

onfr

omth

eac

idvo

lati

leS

extr

acti

onin

the

num

erat

orT

he

hor

izon

tall

ine

repr

esen

tsth

esu

gges

ted

boun

dary

for

oxic

wat

erco

lum

nco

ndi

tion

sfo

rm

oder

nse

dim

ents

03

8(C

anfi

eld

and

Rai

swel

l19

98)

Th

eve

rtic

allin

ere

pres

ents

the

Fep

yFe

HR

boun

dary

for

indi

cati

onof

sulfi

deac

cum

ulat

ion

of0

7w

hic

his

disc

usse

din

the

mai

nte

xtT

he

solid

bars

repr

esen

t1

ofth

ere

spec

tive

data


Fig

3B

oxan

dw

his

ker

plot

sco

mpa

rin

gse

dim

enta

ryM

oco

nce

ntr

atio

ns

from

(A

)O

xic

wat

erco

lum

nse

ttin

gsw

ith

(Mal

colm

198

5Pe

ders

en1

985

Mor

ford

and

oth

ers

2007

Po

ulso

nB

ruck

eran

dot

her

s20

09)

and

wit

hou

t(Z

hen

gan

dot

her

s20

00

Boumln

ing

and

oth

ers

2004

M

orfo

rdan

dot

her

s20

09

Poul

son

Bru

cker

and

oth

ers

2009

Sch

olz

and

oth

ers

2011

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dber

gan

dot

her

s20

12)

appr

ecia

ble

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lfide

con

cen

trat

ion

sIn

terv

alsw

her

eM

ois

asso

ciat

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ith

Mn

enri

chm

ents

(2

wt

M

nin

mos

tcas

es)

are

not

incl

uded

Not

eth

edi

ffer

ence

insc

ale

inpa

rtA

rela

tive

toB

and

C(

B)

Oxi

c(M

alco

lm1

985

Pede

rsen

198

5Sh

imm

ield

and

Pric

e19

86M

orfo

rdan

dE

mer

son

199

9Z

hen

gan

dot

her

s20

00B

oumlnin

gan

dot

her

s20

04S

undb

yan

dot

her

s20

04M

cMan

usan

dot

her

s20

06P

ouls

onan

dot

her

s20

06

Mor

ford

and

oth

ers

2007

Pou

lson

Bru

cker

and

oth

ers

2009

Mor

ford

and

oth

ers

2009

Sch

olz

and

oth

ers

2011

Gol

dber

gan

dot

her

s20

12)

and

low

oxyg

enw

ater

colu

mn

s(B

ron

gers

ma-

San

ders

and

oth

ers

1980

Cal

vert

and

Pric

e19

83M

orfo

rdan

dE

mer

son

199

9Z

hen

gan

dot

her

s20

00N

amer

offa

nd

oth

ers

2002

Boumln

ing

and

oth

ers

2004

McM

anus

and

oth

ers

2006

Pou

lson

and

oth

ers

2006

Pou

lson

Bru

cker

and

oth

ers

2009

Sch

olz

and

oth

ers

2011

)mdashde

fin

edas

15

M

O2

butl

acki

ng

diss

olve

dsu

lfide

(C

)L

owox

ygen

wat

erco

lum

nsi

tes

wit

h(Z

hen

gan

dot

her

s20

00B

oumlnin

gan

dot

her

s20

04P

ouls

onB

ruck

eran

dot

her

s20

09S

chol

zan

dot

her

s20

11)

and

wit

hou

t(Z

hen

gan

dot

her

s20

00

Nam

erof

fan

dot

her

s20

02

Sch

olz

and

oth

ers

2011

)ap

prec

iabl

esu

lfide

con

cen

trat

ion

sin

the

pore

wat

ers

Ala

ckof

appr

ecia

ble

sulfi

deis

defi

ned

bysu

lfide

mea

sure

dbu

t

100

M

su

lfide

mea

sure

dbu

tbe

low

dete

ctio

n

orsu

lfide

not

mea

sure

dbu

tw

ith

elev

ated

diss

olve

dFe

con

cen

trat

ion

s


Fig

4FO

AM

con

cen

trat

ion

profi

les

for

(A)

pore

wat

ersu

lfat

ean

dh

ydro

gen

sulfi

de(

B)

tota

lor

gan

icca

rbon

(TO

C)

and

(C)

wei

ght

perc

ent

sulf

urin

pyri

te

Als

oin

clud

edar

eis

otop

eco

mpo

siti

ons

of(D

)34S

(34S)

ofsu

lfat

ean

ddi

ssol

ved

sulfi

dean

d(E

)33S

(33S)

for

sulf

ate

and

diss

olve

dsu

lfide

In

part

Dd

ata

are

show

nfr

ombo

thth

eco

res

utili

zed

for

mea

sure

men

tin

AB

CE

ofth

isfi

gure

(201

0co

re)

and

prev

ious

lyun

publ

ish

edda

tafr

omco

reFO

AM

-1(A

ller

1980

a19

80b)

Sul

fur

isot

ope

data

are

show

nin

tabl

es1

and

2



TABLE 1




TABLE 2



2 2187 00324 2144 00418 2398 003612 3735 0113 -1895 014916 3600 0104 -1948 015520 3797 0122 -1780 015924 4216 0115 -1707 017928 4363 011732 4428 011936 4365 010240 4380 0116



TA

BL

E3

Res

ults

for

Fe

spec

iati

on

degr

eeof

pyri

tiza

tion

(DO

P)

bulk

sedi

men

tary

Fe

and

Al

conc

entr

atio

ns

and

tota

lor

gani

cca

rbon

(TO

C)

Dep

th

(cm

)Fe

asc

(wt

)Fe

dith

(wt

)Fe

mag

(wt

)Fe

py(w

t )

FeH

Cl(

wt

)

FeT

(wt

)A

l T(w

t )

FeH

RF

e TFe

pyF

e HR

FeTA

lD

OP

TO

C(w

t )

05

002

lt D

L

009

068

137

318

582

025

086

055

033

175

2ltD

L

011

006

065

114

344

661

024

079

052

036

185

40

060

130

050

311

183

166

430

180

550

490

211

206

003

010

006

036

133

296

567

019

065

052

022

122

80

010

040

020

351

053

136

450

140

840

480

251

3110

001

003

002

060

094

272

551

024

091

049

039

101

120

010

020

060

661

022

775

710

270

860

480

392

5014

lt D

L

lt D

L

001

074

116

303

603

025

098

050

039

121

160

010

020

010

650

943

116

190

220

940

500

410

7118

002

003

003

069

100

253

495

031

089

051

041

104

200

050

040

070

711

253

216

040

270

820

530

361

3222

lt D

L

lt D

L

006

093

092

332

667

030

094

050

050

142

240

01lt

DL

0

051

061

243

124

850

360

950

640

461

5226

lt D

L

lt D

L

007

083

112

369

738

024

093

050

043

165

28lt

DL

lt

DL

0

040

931

513

457

010

280

960

490

381

2430

lt D

L

lt D

L

002

086

097

303

569

028

099

053

047

145

320

040

020

080

681

213

176

120

260

830

520

361

4134

003

001

008

059

124

279

589

026

083

047

032

087

36lt

DL

lt

DL

0

030

701

103

196

090

230

960

520

391

5438

lt D

L

001

007

069

120

306

587

025

090

052

036

191

400

030

030

080

661

173

005

730

270

830

520

361

0042

002

001

006

055

114

328

647

019

087

051

033

147

440

020

010

070

711

133

045

700

270

880

530

391

6446

001

lt D

L

009

081

099

331

648

027

089

051

045

149

480

020

010

060

600

773

165

840

220

860

540

441

4250

lt D

L

lt D

L

002

085

084

284

522

031

097

054

050

127

DL

D

etec

tion

lim

it

The

data

are

pres

ente

din

figu

re5


Fig

5(A

)D

isso

lved

pore

wat

erFe

con

cen

trat

ion

s(B

)di

thio

nit

eFe

toto

tal

Fera

tios

(Fe d

ithF

e T)

(C)

degr

eeof

pyri

tiza

tion

(DO

P)a

nd

(D)

rati

osof

hig

hly

reac

tive

Feto

tota

lFe

con

cen

trat

ion

s(F

e HRF

e T)

tota

lFe

toA

lrat

ios

(Fe T

Al T

)an

dpy

riti

zed

Feov

erh

igh

lyre

acti

veFe

(Fe p

yFe

HR)

Th

eve

rtic

alba

rre

pres

ents

the

ran

geof

DO

Ppr

evio

usly

mea

sure

dat

FOA

Mfr

omC

anfi

eld

and

oth

ers

(199

2)



discussion






Fig

6Se

dim

enta

ry(A

)M

oco

nce

ntr

atio

ns

(B)

Mo

Alm

assr

atio

s(C

)po

rew

ater

Mo

con

cen

trat

ion

s(D

)se

dim

enta

ryM

nco

nce

ntr

atio

ns

and

(E)

pore

wat

erM

nco

nce

ntr

atio

ns

Hor

izon

tald

ash

edlin

esre

pres

entt

he

dept

hof

sign

ifica

nts

ulfi

deac

cum

ulat

ion

Sh

aded

area

srep

rese

ntM

oA

lave

rage

shal

eva

lues

from

Tur

ekia

nan

dW

edep

ohl(

1961

)




TABLE 4


Depth (cm)

Pore water Mo (nM)

Bulk Mo (ppm)

05 1574 11 2 1398 11 4 11 6 2965 10 8 10

10 799 10 12 12 14 1151 10 16 13 18 359 11 20 09 22 30 24 09 26 45 28 10 30 139 10 32 09 34 36 10 38 342 09 40 11 42 144 10 44 10 46 148 11 48 10 50 84 12




















[X]t

D2[X]

z2 [X]

z rxn (4)







korg[org][O2]






TABLE 5














Fig

7D

iage

net

icm

odel

resu

lts

Bas

elin

eva

lues

(red

dot)

are

para

met

ersd

eter

min

edfr

omth

eFO

AM

site

and

are

pres

ente

din

tabl

e5

Un

less

oth

erw

ise

indi

cate

dth

em

odel

sen

siti

vity

anal

yses

use

the

FOA

Mva

lues

for

rele

van

tpar

amet

ers

We

expl

ore

the

sen

siti

vity

ofm

arin

eau

thig

enic

Mo

enri

chm

ents

todi

ssol

ved

seaw

ater

Mo

and

O2s

edim

enta

tion

rate

sor

gan

icm

atte

rra

infl

uxan

dpo

rew

ater

H2S

leve

lsov

era

wid

era

nge

ofpa

ram

eter

spac

ere

leva

ntt

oth

atco

nsi

dere

din

figu

re3



most extreme[Mo]





conclusions








REFERENCES






































































































































Fig

2C

ompi

lati

onof

Fesp

ecia

tion

data

from

mod

ern

sedi

men

ts

(A)

Non

-eux

inic

wat

erco

lum

ns

wit

h(C

anfi

eld

1989

Sc

hol

zan

dot

her

s20

14b

Rav

enan

dot

her

s20

16R

iedi

nge

ran

dot

her

s20

17)

and

wit

hou

t(C

anfi

eld

1989

Wijs

man

and

oth

ers

2001

Alle

ran

dot

her

s20

04G

oldb

erg

and

oth

ers

2012

Sch

olz

and

oth

ers

2014

bW

ehrm

ann

and

oth

ers

2014

Hen

kela

nd

oth

ers

2016

Rie

din

ger

and

oth

ers

2017

)po

rew

ater

sulfi

dein

the

hos

tsed

imen

ts(

B)

Eux

inic

(Rai

swel

lan

dC

anfi

eld

1998

Wijs

man

and

oth

ers

2001

Lyo

ns

and

oth

ers

2003

)lo

wox

ygen

(Rai

swel

lan

dC

anfi

eld

1998

Sch

olz

and

oth

ers

2014

bR

aven

and

oth

ers

2016

)an

dox

icw

ater

colu

mn

s(C

anfi

eld

1989

Rai

swel

lan

dC

anfi

eld

1998

Alle

ran

dot

her

s20

04G

oldb

erg

and

oth

ers

2012

Maumlr

zan

dot

her

s20

12Z

hu

and

oth

ers

2012

Aqu

ilin

aan

dot

her

s20

14S

chol

zan

dot

her

s20

14b

Weh

rman

nan

dot

her

s20

14P

eket

ian

dot

her

s20

15Z

hu

and

oth

ers

2015

Hen

kela

nd

oth

ers

2016

Rie

din

ger

and

oth

ers

2017

)L

owox

ygen

isde

fin

edas

15

M

O2

butl

acki

ng

dete

cted

sulfi

deN

otab

lyt

he

lsquohig

hly

reac

tive

rsquoFe

isde

term

ined

diff

eren

tly

betw

een

the

publ

icat

ion

sin

clud

ing

the

sequ

enti

alex

trac

tion

ofPo

ulto

nan

dC

anfi

eld

(200

5)i

tspr

edec

esso

rs(f

orex

ampl

eR

aisw

ella

nd

Can

fiel

d19

98A

ller

and

oth

ers

2004

)an

dot

her

mod

ifica

tion

s(f

orex

ampl

eR

aven

and

oth

ers

2016

)W

hen

avai

labl

eFe

py

FeH

Rin

clud

esir

onfr

omth

eac

idvo

lati

leS

extr

acti

onin

the

num

erat

orT

he

hor

izon

tall

ine

repr

esen

tsth

esu

gges

ted

boun

dary

for

oxic

wat

erco

lum

nco

ndi

tion

sfo

rm

oder

nse

dim

ents

03

8(C

anfi

eld

and

Rai

swel

l19

98)

Th

eve

rtic

allin

ere

pres

ents

the

Fep

yFe

HR

boun

dary

for

indi

cati

onof

sulfi

deac

cum

ulat

ion

of0

7w

hic

his

disc

usse

din

the

mai

nte

xtT

he

solid

bars

repr

esen

t1

ofth

ere

spec

tive

data


Fig

3B

oxan

dw

his

ker

plot

sco

mpa

rin

gse

dim

enta

ryM

oco

nce

ntr

atio

ns

from

(A

)O

xic

wat

erco

lum

nse

ttin

gsw

ith

(Mal

colm

198

5Pe

ders

en1

985

Mor

ford

and

oth

ers

2007

Po

ulso

nB

ruck

eran

dot

her

s20

09)

and

wit

hou

t(Z

hen

gan

dot

her

s20

00

Boumln

ing

and

oth

ers

2004

M

orfo

rdan

dot

her

s20

09

Poul

son

Bru

cker

and

oth

ers

2009

Sch

olz

and

oth

ers

2011

Gol

dber

gan

dot

her

s20

12)

appr

ecia

ble

pore

wat

ersu

lfide

con

cen

trat

ion

sIn

terv

alsw

her

eM

ois

asso

ciat

edw

ith

Mn

enri

chm

ents

(2

wt

M

nin

mos

tcas

es)

are

not

incl

uded

Not

eth

edi

ffer

ence

insc

ale

inpa

rtA

rela

tive

toB

and

C(

B)

Oxi

c(M

alco

lm1

985

Pede

rsen

198

5Sh

imm

ield

and

Pric

e19

86M

orfo

rdan

dE

mer

son

199

9Z

hen

gan

dot

her

s20

00B

oumlnin

gan

dot

her

s20

04S

undb

yan

dot

her

s20

04M

cMan

usan

dot

her

s20

06P

ouls

onan

dot

her

s20

06

Mor

ford

and

oth

ers

2007

Pou

lson

Bru

cker

and

oth

ers

2009

Mor

ford

and

oth

ers

2009

Sch

olz

and

oth

ers

2011

Gol

dber

gan

dot

her

s20

12)

and

low

oxyg

enw

ater

colu

mn

s(B

ron

gers

ma-

San

ders

and

oth

ers

1980

Cal

vert

and

Pric

e19

83M

orfo

rdan

dE

mer

son

199

9Z

hen

gan

dot

her

s20

00N

amer

offa

nd

oth

ers

2002

Boumln

ing

and

oth

ers

2004

McM

anus

and

oth

ers

2006

Pou

lson

and

oth

ers

2006

Pou

lson

Bru

cker

and

oth

ers

2009

Sch

olz

and

oth

ers

2011

)mdashde

fin

edas

15

M

O2

butl

acki

ng

diss

olve

dsu

lfide

(C

)L

owox

ygen

wat

erco

lum

nsi

tes

wit

h(Z

hen

gan

dot

her

s20

00B

oumlnin

gan

dot

her

s20

04P

ouls

onB

ruck

eran

dot

her

s20

09S

chol

zan

dot

her

s20

11)

and

wit

hou

t(Z

hen

gan

dot

her

s20

00

Nam

erof

fan

dot

her

s20

02

Sch

olz

and

oth

ers

2011

)ap

prec

iabl

esu

lfide

con

cen

trat

ion

sin

the

pore

wat

ers

Ala

ckof

appr

ecia

ble

sulfi

deis

defi

ned

bysu

lfide

mea

sure

dbu

t

100

M

su

lfide

mea

sure

dbu

tbe

low

dete

ctio

n

orsu

lfide

not

mea

sure

dbu

tw

ith

elev

ated

diss

olve

dFe

con

cen

trat

ion

s


Fig

4FO

AM

con

cen

trat

ion

profi

les

for

(A)

pore

wat

ersu

lfat

ean

dh

ydro

gen

sulfi

de(

B)

tota

lor

gan

icca

rbon

(TO

C)

and

(C)

wei

ght

perc

ent

sulf

urin

pyri

te

Als

oin

clud

edar

eis

otop

eco

mpo

siti

ons

of(D

)34S

(34S)

ofsu

lfat

ean

ddi

ssol

ved

sulfi

dean

d(E

)33S

(33S)

for

sulf

ate

and

diss

olve

dsu

lfide

In

part

Dd

ata

are

show

nfr

ombo

thth

eco

res

utili

zed

for

mea

sure

men

tin

AB

CE

ofth

isfi

gure

(201

0co

re)

and

prev

ious

lyun

publ

ish

edda

tafr

omco

reFO

AM

-1(A

ller

1980

a19

80b)

Sul

fur

isot

ope

data

are

show

nin

tabl

es1

and

2



TABLE 1




TABLE 2



2 2187 00324 2144 00418 2398 003612 3735 0113 -1895 014916 3600 0104 -1948 015520 3797 0122 -1780 015924 4216 0115 -1707 017928 4363 011732 4428 011936 4365 010240 4380 0116



TA

BL

E3

Res

ults

for

Fe

spec

iati

on

degr

eeof

pyri

tiza

tion

(DO

P)

bulk

sedi

men

tary

Fe

and

Al

conc

entr

atio

ns

and

tota

lor

gani

cca

rbon

(TO

C)

Dep

th

(cm

)Fe

asc

(wt

)Fe

dith

(wt

)Fe

mag

(wt

)Fe

py(w

t )

FeH

Cl(

wt

)

FeT

(wt

)A

l T(w

t )

FeH

RF

e TFe

pyF

e HR

FeTA

lD

OP

TO

C(w

t )

05

002

lt D

L

009

068

137

318

582

025

086

055

033

175

2ltD

L

011

006

065

114

344

661

024

079

052

036

185

40

060

130

050

311

183

166

430

180

550

490

211

206

003

010

006

036

133

296

567

019

065

052

022

122

80

010

040

020

351

053

136

450

140

840

480

251

3110

001

003

002

060

094

272

551

024

091

049

039

101

120

010

020

060

661

022

775

710

270

860

480

392

5014

lt D

L

lt D

L

001

074

116

303

603

025

098

050

039

121

160

010

020

010

650

943

116

190

220

940

500

410

7118

002

003

003

069

100

253

495

031

089

051

041

104

200

050

040

070

711

253

216

040

270

820

530

361

3222

lt D

L

lt D

L

006

093

092

332

667

030

094

050

050

142

240

01lt

DL

0

051

061

243

124

850

360

950

640

461

5226

lt D

L

lt D

L

007

083

112

369

738

024

093

050

043

165

28lt

DL

lt

DL

0

040

931

513

457

010

280

960

490

381

2430

lt D

L

lt D

L

002

086

097

303

569

028

099

053

047

145

320

040

020

080

681

213

176

120

260

830

520

361

4134

003

001

008

059

124

279

589

026

083

047

032

087

36lt

DL

lt

DL

0

030

701

103

196

090

230

960

520

391

5438

lt D

L

001

007

069

120

306

587

025

090

052

036

191

400

030

030

080

661

173

005

730

270

830

520

361

0042

002

001

006

055

114

328

647

019

087

051

033

147

440

020

010

070

711

133

045

700

270

880

530

391

6446

001

lt D

L

009

081

099

331

648

027

089

051

045

149

480

020

010

060

600

773

165

840

220

860

540

441

4250

lt D

L

lt D

L

002

085

084

284

522

031

097

054

050

127

DL

D

etec

tion

lim

it

The

data

are

pres

ente

din

figu

re5


Fig

5(A

)D

isso

lved

pore

wat

erFe

con

cen

trat

ion

s(B

)di

thio

nit

eFe

toto

tal

Fera

tios

(Fe d

ithF

e T)

(C)

degr

eeof

pyri

tiza

tion

(DO

P)a

nd

(D)

rati

osof

hig

hly

reac

tive

Feto

tota

lFe

con

cen

trat

ion

s(F

e HRF

e T)

tota

lFe

toA

lrat

ios

(Fe T

Al T

)an

dpy

riti

zed

Feov

erh

igh

lyre

acti

veFe

(Fe p

yFe

HR)

Th

eve

rtic

alba

rre

pres

ents

the

ran

geof

DO

Ppr

evio

usly

mea

sure

dat

FOA

Mfr

omC

anfi

eld

and

oth

ers

(199

2)



discussion






Fig

6Se

dim

enta

ry(A

)M

oco

nce

ntr

atio

ns

(B)

Mo

Alm

assr

atio

s(C

)po

rew

ater

Mo

con

cen

trat

ion

s(D

)se

dim

enta

ryM

nco

nce

ntr

atio

ns

and

(E)

pore

wat

erM

nco

nce

ntr

atio

ns

Hor

izon

tald

ash

edlin

esre

pres

entt

he

dept

hof

sign

ifica

nts

ulfi

deac

cum

ulat

ion

Sh

aded

area

srep

rese

ntM

oA

lave

rage

shal

eva

lues

from

Tur

ekia

nan

dW

edep

ohl(

1961

)




TABLE 4


Depth (cm)

Pore water Mo (nM)

Bulk Mo (ppm)

05 1574 11 2 1398 11 4 11 6 2965 10 8 10

10 799 10 12 12 14 1151 10 16 13 18 359 11 20 09 22 30 24 09 26 45 28 10 30 139 10 32 09 34 36 10 38 342 09 40 11 42 144 10 44 10 46 148 11 48 10 50 84 12




















[X]t

D2[X]

z2 [X]

z rxn (4)







korg[org][O2]






TABLE 5














Fig

7D

iage

net

icm

odel

resu

lts

Bas

elin

eva

lues

(red

dot)

are

para

met

ersd

eter

min

edfr

omth

eFO

AM

site

and

are

pres

ente

din

tabl

e5

Un

less

oth

erw

ise

indi

cate

dth

em

odel

sen

siti

vity

anal

yses

use

the

FOA

Mva

lues

for

rele

van

tpar

amet

ers

We

expl

ore

the

sen

siti

vity

ofm

arin

eau

thig

enic

Mo

enri

chm

ents

todi

ssol

ved

seaw

ater

Mo

and

O2s

edim

enta

tion

rate

sor

gan

icm

atte

rra

infl

uxan

dpo

rew

ater

H2S

leve

lsov

era

wid

era

nge

ofpa

ram

eter

spac

ere

leva

ntt

oth

atco

nsi

dere

din

figu

re3



most extreme[Mo]





conclusions








REFERENCES






































































































































Fig

3B

oxan

dw

his

ker

plot

sco

mpa

rin

gse

dim

enta

ryM

oco

nce

ntr

atio

ns

from

(A

)O

xic

wat

erco

lum

nse

ttin

gsw

ith

(Mal

colm

198

5Pe

ders

en1

985

Mor

ford

and

oth

ers

2007

Po

ulso

nB

ruck

eran

dot

her

s20

09)

and

wit

hou

t(Z

hen

gan

dot

her

s20

00

Boumln

ing

and

oth

ers

2004

M

orfo

rdan

dot

her

s20

09

Poul

son

Bru

cker

and

oth

ers

2009

Sch

olz

and

oth

ers

2011

Gol

dber

gan

dot

her

s20

12)

appr

ecia

ble

pore

wat

ersu

lfide

con

cen

trat

ion

sIn

terv

alsw

her

eM

ois

asso

ciat

edw

ith

Mn

enri

chm

ents

(2

wt

M

nin

mos

tcas

es)

are

not

incl

uded

Not

eth

edi

ffer

ence

insc

ale

inpa

rtA

rela

tive

toB

and

C(

B)

Oxi

c(M

alco

lm1

985

Pede

rsen

198

5Sh

imm

ield

and

Pric

e19

86M

orfo

rdan

dE

mer

son

199

9Z

hen

gan

dot

her

s20

00B

oumlnin

gan

dot

her

s20

04S

undb

yan

dot

her

s20

04M

cMan

usan

dot

her

s20

06P

ouls

onan

dot

her

s20

06

Mor

ford

and

oth

ers

2007

Pou

lson

Bru

cker

and

oth

ers

2009

Mor

ford

and

oth

ers

2009

Sch

olz

and

oth

ers

2011

Gol

dber

gan

dot

her

s20

12)

and

low

oxyg

enw

ater

colu

mn

s(B

ron

gers

ma-

San

ders

and

oth

ers

1980

Cal

vert

and

Pric

e19

83M

orfo

rdan

dE

mer

son

199

9Z

hen

gan

dot

her

s20

00N

amer

offa

nd

oth

ers

2002

Boumln

ing

and

oth

ers

2004

McM

anus

and

oth

ers

2006

Pou

lson

and

oth

ers

2006

Pou

lson

Bru

cker

and

oth

ers

2009

Sch

olz

and

oth

ers

2011

)mdashde

fin

edas

15

M

O2

butl

acki

ng

diss

olve

dsu

lfide

(C

)L

owox

ygen

wat

erco

lum

nsi

tes

wit

h(Z

hen

gan

dot

her

s20

00B

oumlnin

gan

dot

her

s20

04P

ouls

onB

ruck

eran

dot

her

s20

09S

chol

zan

dot

her

s20

11)

and

wit

hou

t(Z

hen

gan

dot

her

s20

00

Nam

erof

fan

dot

her

s20

02

Sch

olz

and

oth

ers

2011

)ap

prec

iabl

esu

lfide

con

cen

trat

ion

sin

the

pore

wat

ers

Ala

ckof

appr

ecia

ble

sulfi

deis

defi

ned

bysu

lfide

mea

sure

dbu

t

100

M

su

lfide

mea

sure

dbu

tbe

low

dete

ctio

n

orsu

lfide

not

mea

sure

dbu

tw

ith

elev

ated

diss

olve

dFe

con

cen

trat

ion

s


Fig

4FO

AM

con

cen

trat

ion

profi

les

for

(A)

pore

wat

ersu

lfat

ean

dh

ydro

gen

sulfi

de(

B)

tota

lor

gan

icca

rbon

(TO

C)

and

(C)

wei

ght

perc

ent

sulf

urin

pyri

te

Als

oin

clud

edar

eis

otop

eco

mpo

siti

ons

of(D

)34S

(34S)

ofsu

lfat

ean

ddi

ssol

ved

sulfi

dean

d(E

)33S

(33S)

for

sulf

ate

and

diss

olve

dsu

lfide

In

part

Dd

ata

are

show

nfr

ombo

thth

eco

res

utili

zed

for

mea

sure

men

tin

AB

CE

ofth

isfi

gure

(201

0co

re)

and

prev

ious

lyun

publ

ish

edda

tafr

omco

reFO

AM

-1(A

ller

1980

a19

80b)

Sul

fur

isot

ope

data

are

show

nin

tabl

es1

and

2



TABLE 1




TABLE 2



2 2187 00324 2144 00418 2398 003612 3735 0113 -1895 014916 3600 0104 -1948 015520 3797 0122 -1780 015924 4216 0115 -1707 017928 4363 011732 4428 011936 4365 010240 4380 0116



TA

BL

E3

Res

ults

for

Fe

spec

iati

on

degr

eeof

pyri

tiza

tion

(DO

P)

bulk

sedi

men

tary

Fe

and

Al

conc

entr

atio

ns

and

tota

lor

gani

cca

rbon

(TO

C)

Dep

th

(cm

)Fe

asc

(wt

)Fe

dith

(wt

)Fe

mag

(wt

)Fe

py(w

t )

FeH

Cl(

wt

)

FeT

(wt

)A

l T(w

t )

FeH

RF

e TFe

pyF

e HR

FeTA

lD

OP

TO

C(w

t )

05

002

lt D

L

009

068

137

318

582

025

086

055

033

175

2ltD

L

011

006

065

114

344

661

024

079

052

036

185

40

060

130

050

311

183

166

430

180

550

490

211

206

003

010

006

036

133

296

567

019

065

052

022

122

80

010

040

020

351

053

136

450

140

840

480

251

3110

001

003

002

060

094

272

551

024

091

049

039

101

120

010

020

060

661

022

775

710

270

860

480

392

5014

lt D

L

lt D

L

001

074

116

303

603

025

098

050

039

121

160

010

020

010

650

943

116

190

220

940

500

410

7118

002

003

003

069

100

253

495

031

089

051

041

104

200

050

040

070

711

253

216

040

270

820

530

361

3222

lt D

L

lt D

L

006

093

092

332

667

030

094

050

050

142

240

01lt

DL

0

051

061

243

124

850

360

950

640

461

5226

lt D

L

lt D

L

007

083

112

369

738

024

093

050

043

165

28lt

DL

lt

DL

0

040

931

513

457

010

280

960

490

381

2430

lt D

L

lt D

L

002

086

097

303

569

028

099

053

047

145

320

040

020

080

681

213

176

120

260

830

520

361

4134

003

001

008

059

124

279

589

026

083

047

032

087

36lt

DL

lt

DL

0

030

701

103

196

090

230

960

520

391

5438

lt D

L

001

007

069

120

306

587

025

090

052

036

191

400

030

030

080

661

173

005

730

270

830

520

361

0042

002

001

006

055

114

328

647

019

087

051

033

147

440

020

010

070

711

133

045

700

270

880

530

391

6446

001

lt D

L

009

081

099

331

648

027

089

051

045

149

480

020

010

060

600

773

165

840

220

860

540

441

4250

lt D

L

lt D

L

002

085

084

284

522

031

097

054

050

127

DL

D

etec

tion

lim

it

The

data

are

pres

ente

din

figu

re5


Fig

5(A

)D

isso

lved

pore

wat

erFe

con

cen

trat

ion

s(B

)di

thio

nit

eFe

toto

tal

Fera

tios

(Fe d

ithF

e T)

(C)

degr

eeof

pyri

tiza

tion

(DO

P)a

nd

(D)

rati

osof

hig

hly

reac

tive

Feto

tota

lFe

con

cen

trat

ion

s(F

e HRF

e T)

tota

lFe

toA

lrat

ios

(Fe T

Al T

)an

dpy

riti

zed

Feov

erh

igh

lyre

acti

veFe

(Fe p

yFe

HR)

Th

eve

rtic

alba

rre

pres

ents

the

ran

geof

DO

Ppr

evio

usly

mea

sure

dat

FOA

Mfr

omC

anfi

eld

and

oth

ers

(199

2)



discussion






Fig

6Se

dim

enta

ry(A

)M

oco

nce

ntr

atio

ns

(B)

Mo

Alm

assr

atio

s(C

)po

rew

ater

Mo

con

cen

trat

ion

s(D

)se

dim

enta

ryM

nco

nce

ntr

atio

ns

and

(E)

pore

wat

erM

nco

nce

ntr

atio

ns

Hor

izon

tald

ash

edlin

esre

pres

entt

he

dept

hof

sign

ifica

nts

ulfi

deac

cum

ulat

ion

Sh

aded

area

srep

rese

ntM

oA

lave

rage

shal

eva

lues

from

Tur

ekia

nan

dW

edep

ohl(

1961

)




TABLE 4


Depth (cm)

Pore water Mo (nM)

Bulk Mo (ppm)

05 1574 11 2 1398 11 4 11 6 2965 10 8 10

10 799 10 12 12 14 1151 10 16 13 18 359 11 20 09 22 30 24 09 26 45 28 10 30 139 10 32 09 34 36 10 38 342 09 40 11 42 144 10 44 10 46 148 11 48 10 50 84 12




















[X]t

D2[X]

z2 [X]

z rxn (4)







korg[org][O2]






TABLE 5














Fig

7D

iage

net

icm

odel

resu

lts

Bas

elin

eva

lues

(red

dot)

are

para

met

ersd

eter

min

edfr

omth

eFO

AM

site

and

are

pres

ente

din

tabl

e5

Un

less

oth

erw

ise

indi

cate

dth

em

odel

sen

siti

vity

anal

yses

use

the

FOA

Mva

lues

for

rele

van

tpar

amet

ers

We

expl

ore

the

sen

siti

vity

ofm

arin

eau

thig

enic

Mo

enri

chm

ents

todi

ssol

ved

seaw

ater

Mo

and

O2s

edim

enta

tion

rate

sor

gan

icm

atte

rra

infl

uxan

dpo

rew

ater

H2S

leve

lsov

era

wid

era

nge

ofpa

ram

eter

spac

ere

leva

ntt

oth

atco

nsi

dere

din

figu

re3



most extreme[Mo]





conclusions








REFERENCES






































































































































Fig

4FO

AM

con

cen

trat

ion

profi

les

for

(A)

pore

wat

ersu

lfat

ean

dh

ydro

gen

sulfi

de(

B)

tota

lor

gan

icca

rbon

(TO

C)

and

(C)

wei

ght

perc

ent

sulf

urin

pyri

te

Als

oin

clud

edar

eis

otop

eco

mpo

siti

ons

of(D

)34S

(34S)

ofsu

lfat

ean

ddi

ssol

ved

sulfi

dean

d(E

)33S

(33S)

for

sulf

ate

and

diss

olve

dsu

lfide

In

part

Dd

ata

are

show

nfr

ombo

thth

eco

res

utili

zed

for

mea

sure

men

tin

AB

CE

ofth

isfi

gure

(201

0co

re)

and

prev

ious

lyun

publ

ish

edda

tafr

omco

reFO

AM

-1(A

ller

1980

a19

80b)

Sul

fur

isot

ope

data

are

show

nin

tabl

es1

and

2



TABLE 1




TABLE 2



2 2187 00324 2144 00418 2398 003612 3735 0113 -1895 014916 3600 0104 -1948 015520 3797 0122 -1780 015924 4216 0115 -1707 017928 4363 011732 4428 011936 4365 010240 4380 0116



TA

BL

E3

Res

ults

for

Fe

spec

iati

on

degr

eeof

pyri

tiza

tion

(DO

P)

bulk

sedi

men

tary

Fe

and

Al

conc

entr

atio

ns

and

tota

lor

gani

cca

rbon

(TO

C)

Dep

th

(cm

)Fe

asc

(wt

)Fe

dith

(wt

)Fe

mag

(wt

)Fe

py(w

t )

FeH

Cl(

wt

)

FeT

(wt

)A

l T(w

t )

FeH

RF

e TFe

pyF

e HR

FeTA

lD

OP

TO

C(w

t )

05

002

lt D

L

009

068

137

318

582

025

086

055

033

175

2ltD

L

011

006

065

114

344

661

024

079

052

036

185

40

060

130

050

311

183

166

430

180

550

490

211

206

003

010

006

036

133

296

567

019

065

052

022

122

80

010

040

020

351

053

136

450

140

840

480

251

3110

001

003

002

060

094

272

551

024

091

049

039

101

120

010

020

060

661

022

775

710

270

860

480

392

5014

lt D

L

lt D

L

001

074

116

303

603

025

098

050

039

121

160

010

020

010

650

943

116

190

220

940

500

410

7118

002

003

003

069

100

253

495

031

089

051

041

104

200

050

040

070

711

253

216

040

270

820

530

361

3222

lt D

L

lt D

L

006

093

092

332

667

030

094

050

050

142

240

01lt

DL

0

051

061

243

124

850

360

950

640

461

5226

lt D

L

lt D

L

007

083

112

369

738

024

093

050

043

165

28lt

DL

lt

DL

0

040

931

513

457

010

280

960

490

381

2430

lt D

L

lt D

L

002

086

097

303

569

028

099

053

047

145

320

040

020

080

681

213

176

120

260

830

520

361

4134

003

001

008

059

124

279

589

026

083

047

032

087

36lt

DL

lt

DL

0

030

701

103

196

090

230

960

520

391

5438

lt D

L

001

007

069

120

306

587

025

090

052

036

191

400

030

030

080

661

173

005

730

270

830

520

361

0042

002

001

006

055

114

328

647

019

087

051

033

147

440

020

010

070

711

133

045

700

270

880

530

391

6446

001

lt D

L

009

081

099

331

648

027

089

051

045

149

480

020

010

060

600

773

165

840

220

860

540

441

4250

lt D

L

lt D

L

002

085

084

284

522

031

097

054

050

127

DL

D

etec

tion

lim

it

The

data

are

pres

ente

din

figu

re5


Fig

5(A

)D

isso

lved

pore

wat

erFe

con

cen

trat

ion

s(B

)di

thio

nit

eFe

toto

tal

Fera

tios

(Fe d

ithF

e T)

(C)

degr

eeof

pyri

tiza

tion

(DO

P)a

nd

(D)

rati

osof

hig

hly

reac

tive

Feto

tota

lFe

con

cen

trat

ion

s(F

e HRF

e T)

tota

lFe

toA

lrat

ios

(Fe T

Al T

)an

dpy

riti

zed

Feov

erh

igh

lyre

acti

veFe

(Fe p

yFe

HR)

Th

eve

rtic

alba

rre

pres

ents

the

ran

geof

DO

Ppr

evio

usly

mea

sure

dat

FOA

Mfr

omC

anfi

eld

and

oth

ers

(199

2)



discussion






Fig

6Se

dim

enta

ry(A

)M

oco

nce

ntr

atio

ns

(B)

Mo

Alm

assr

atio

s(C

)po

rew

ater

Mo

con

cen

trat

ion

s(D

)se

dim

enta

ryM

nco

nce

ntr

atio

ns

and

(E)

pore

wat

erM

nco

nce

ntr

atio

ns

Hor

izon

tald

ash

edlin

esre

pres

entt

he

dept

hof

sign

ifica

nts

ulfi

deac

cum

ulat

ion

Sh

aded

area

srep

rese

ntM

oA

lave

rage

shal

eva

lues

from

Tur

ekia

nan

dW

edep

ohl(

1961

)




TABLE 4


Depth (cm)

Pore water Mo (nM)

Bulk Mo (ppm)

05 1574 11 2 1398 11 4 11 6 2965 10 8 10

10 799 10 12 12 14 1151 10 16 13 18 359 11 20 09 22 30 24 09 26 45 28 10 30 139 10 32 09 34 36 10 38 342 09 40 11 42 144 10 44 10 46 148 11 48 10 50 84 12




















[X]t

D2[X]

z2 [X]

z rxn (4)







korg[org][O2]






TABLE 5














Fig

7D

iage

net

icm

odel

resu

lts

Bas

elin

eva

lues

(red

dot)

are

para

met

ersd

eter

min

edfr

omth

eFO

AM

site

and

are

pres

ente

din

tabl

e5

Un

less

oth

erw

ise

indi

cate

dth

em

odel

sen

siti

vity

anal

yses

use

the

FOA

Mva

lues

for

rele

van

tpar

amet

ers

We

expl

ore

the

sen

siti

vity

ofm

arin

eau

thig

enic

Mo

enri

chm

ents

todi

ssol

ved

seaw

ater

Mo

and

O2s

edim

enta

tion

rate

sor

gan

icm

atte

rra

infl

uxan

dpo

rew

ater

H2S

leve

lsov

era

wid

era

nge

ofpa

ram

eter

spac

ere

leva

ntt

oth

atco

nsi

dere

din

figu

re3



most extreme[Mo]





conclusions








REFERENCES







































































































































TABLE 1




TABLE 2



2 2187 00324 2144 00418 2398 003612 3735 0113 -1895 014916 3600 0104 -1948 015520 3797 0122 -1780 015924 4216 0115 -1707 017928 4363 011732 4428 011936 4365 010240 4380 0116



TA

BL

E3

Res

ults

for

Fe

spec

iati

on

degr

eeof

pyri

tiza

tion

(DO

P)

bulk

sedi

men

tary

Fe

and

Al

conc

entr

atio

ns

and

tota

lor

gani

cca

rbon

(TO

C)

Dep

th

(cm

)Fe

asc

(wt

)Fe

dith

(wt

)Fe

mag

(wt

)Fe

py(w

t )

FeH

Cl(

wt

)

FeT

(wt

)A

l T(w

t )

FeH

RF

e TFe

pyF

e HR

FeTA

lD

OP

TO

C(w

t )

05

002

lt D

L

009

068

137

318

582

025

086

055

033

175

2ltD

L

011

006

065

114

344

661

024

079

052

036

185

40

060

130

050

311

183

166

430

180

550

490

211

206

003

010

006

036

133

296

567

019

065

052

022

122

80

010

040

020

351

053

136

450

140

840

480

251

3110

001

003

002

060

094

272

551

024

091

049

039

101

120

010

020

060

661

022

775

710

270

860

480

392

5014

lt D

L

lt D

L

001

074

116

303

603

025

098

050

039

121

160

010

020

010

650

943

116

190

220

940

500

410

7118

002

003

003

069

100

253

495

031

089

051

041

104

200

050

040

070

711

253

216

040

270

820

530

361

3222

lt D

L

lt D

L

006

093

092

332

667

030

094

050

050

142

240

01lt

DL

0

051

061

243

124

850

360

950

640

461

5226

lt D

L

lt D

L

007

083

112

369

738

024

093

050

043

165

28lt

DL

lt

DL

0

040

931

513

457

010

280

960

490

381

2430

lt D

L

lt D

L

002

086

097

303

569

028

099

053

047

145

320

040

020

080

681

213

176

120

260

830

520

361

4134

003

001

008

059

124

279

589

026

083

047

032

087

36lt

DL

lt

DL

0

030

701

103

196

090

230

960

520

391

5438

lt D

L

001

007

069

120

306

587

025

090

052

036

191

400

030

030

080

661

173

005

730

270

830

520

361

0042

002

001

006

055

114

328

647

019

087

051

033

147

440

020

010

070

711

133

045

700

270

880

530

391

6446

001

lt D

L

009

081

099

331

648

027

089

051

045

149

480

020

010

060

600

773

165

840

220

860

540

441

4250

lt D

L

lt D

L

002

085

084

284

522

031

097

054

050

127

DL

D

etec

tion

lim

it

The

data

are

pres

ente

din

figu

re5


Fig

5(A

)D

isso

lved

pore

wat

erFe

con

cen

trat

ion

s(B

)di

thio

nit

eFe

toto

tal

Fera

tios

(Fe d

ithF

e T)

(C)

degr

eeof

pyri

tiza

tion

(DO

P)a

nd

(D)

rati

osof

hig

hly

reac

tive

Feto

tota

lFe

con

cen

trat

ion

s(F

e HRF

e T)

tota

lFe

toA

lrat

ios

(Fe T

Al T

)an

dpy

riti

zed

Feov

erh

igh

lyre

acti

veFe

(Fe p

yFe

HR)

Th

eve

rtic

alba

rre

pres

ents

the

ran

geof

DO

Ppr

evio

usly

mea

sure

dat

FOA

Mfr

omC

anfi

eld

and

oth

ers

(199

2)



discussion






Fig

6Se

dim

enta

ry(A

)M

oco

nce

ntr

atio

ns

(B)

Mo

Alm

assr

atio

s(C

)po

rew

ater

Mo

con

cen

trat

ion

s(D

)se

dim

enta

ryM

nco

nce

ntr

atio

ns

and

(E)

pore

wat

erM

nco

nce

ntr

atio

ns

Hor

izon

tald

ash

edlin

esre

pres

entt

he

dept

hof

sign

ifica

nts

ulfi

deac

cum

ulat

ion

Sh

aded

area

srep

rese

ntM

oA

lave

rage

shal

eva

lues

from

Tur

ekia

nan

dW

edep

ohl(

1961

)




TABLE 4


Depth (cm)

Pore water Mo (nM)

Bulk Mo (ppm)

05 1574 11 2 1398 11 4 11 6 2965 10 8 10

10 799 10 12 12 14 1151 10 16 13 18 359 11 20 09 22 30 24 09 26 45 28 10 30 139 10 32 09 34 36 10 38 342 09 40 11 42 144 10 44 10 46 148 11 48 10 50 84 12




















[X]t

D2[X]

z2 [X]

z rxn (4)







korg[org][O2]






TABLE 5














Fig

7D

iage

net

icm

odel

resu

lts

Bas

elin

eva

lues

(red

dot)

are

para

met

ersd

eter

min

edfr

omth

eFO

AM

site

and

are

pres

ente

din

tabl

e5

Un

less

oth

erw

ise

indi

cate

dth

em

odel

sen

siti

vity

anal

yses

use

the

FOA

Mva

lues

for

rele

van

tpar

amet

ers

We

expl

ore

the

sen

siti

vity

ofm

arin

eau

thig

enic

Mo

enri

chm

ents

todi

ssol

ved

seaw

ater

Mo

and

O2s

edim

enta

tion

rate

sor

gan

icm

atte

rra

infl

uxan

dpo

rew

ater

H2S

leve

lsov

era

wid

era

nge

ofpa

ram

eter

spac

ere

leva

ntt

oth

atco

nsi

dere

din

figu

re3



most extreme[Mo]





conclusions








REFERENCES






































































































































TA

BL

E3

Res

ults

for

Fe

spec

iati

on

degr

eeof

pyri

tiza

tion

(DO

P)

bulk

sedi

men

tary

Fe

and

Al

conc

entr

atio

ns

and

tota

lor

gani

cca

rbon

(TO

C)

Dep

th

(cm

)Fe

asc

(wt

)Fe

dith

(wt

)Fe

mag

(wt

)Fe

py(w

t )

FeH

Cl(

wt

)

FeT

(wt

)A

l T(w

t )

FeH

RF

e TFe

pyF

e HR

FeTA

lD

OP

TO

C(w

t )

05

002

lt D

L

009

068

137

318

582

025

086

055

033

175

2ltD

L

011

006

065

114

344

661

024

079

052

036

185

40

060

130

050

311

183

166

430

180

550

490

211

206

003

010

006

036

133

296

567

019

065

052

022

122

80

010

040

020

351

053

136

450

140

840

480

251

3110

001

003

002

060

094

272

551

024

091

049

039

101

120

010

020

060

661

022

775

710

270

860

480

392

5014

lt D

L

lt D

L

001

074

116

303

603

025

098

050

039

121

160

010

020

010

650

943

116

190

220

940

500

410

7118

002

003

003

069

100

253

495

031

089

051

041

104

200

050

040

070

711

253

216

040

270

820

530

361

3222

lt D

L

lt D

L

006

093

092

332

667

030

094

050

050

142

240

01lt

DL

0

051

061

243

124

850

360

950

640

461

5226

lt D

L

lt D

L

007

083

112

369

738

024

093

050

043

165

28lt

DL

lt

DL

0

040

931

513

457

010

280

960

490

381

2430

lt D

L

lt D

L

002

086

097

303

569

028

099

053

047

145

320

040

020

080

681

213

176

120

260

830

520

361

4134

003

001

008

059

124

279

589

026

083

047

032

087

36lt

DL

lt

DL

0

030

701

103

196

090

230

960

520

391

5438

lt D

L

001

007

069

120

306

587

025

090

052

036

191

400

030

030

080

661

173

005

730

270

830

520

361

0042

002

001

006

055

114

328

647

019

087

051

033

147

440

020

010

070

711

133

045

700

270

880

530

391

6446

001

lt D

L

009

081

099

331

648

027

089

051

045

149

480

020

010

060

600

773

165

840

220

860

540

441

4250

lt D

L

lt D

L

002

085

084

284

522

031

097

054

050

127

DL

D

etec

tion

lim

it

The

data

are

pres

ente

din

figu

re5


Fig

5(A

)D

isso

lved

pore

wat

erFe

con

cen

trat

ion

s(B

)di

thio

nit

eFe

toto

tal

Fera

tios

(Fe d

ithF

e T)

(C)

degr

eeof

pyri

tiza

tion

(DO

P)a

nd

(D)

rati

osof

hig

hly

reac

tive

Feto

tota

lFe

con

cen

trat

ion

s(F

e HRF

e T)

tota

lFe

toA

lrat

ios

(Fe T

Al T

)an

dpy

riti

zed

Feov

erh

igh

lyre

acti

veFe

(Fe p

yFe

HR)

Th

eve

rtic

alba

rre

pres

ents

the

ran

geof

DO

Ppr

evio

usly

mea

sure

dat

FOA

Mfr

omC

anfi

eld

and

oth

ers

(199

2)



discussion






Fig

6Se

dim

enta

ry(A

)M

oco

nce

ntr

atio

ns

(B)

Mo

Alm

assr

atio

s(C

)po

rew

ater

Mo

con

cen

trat

ion

s(D

)se

dim

enta

ryM

nco

nce

ntr

atio

ns

and

(E)

pore

wat

erM

nco

nce

ntr

atio

ns

Hor

izon

tald

ash

edlin

esre

pres

entt

he

dept

hof

sign

ifica

nts

ulfi

deac

cum

ulat

ion

Sh

aded

area

srep

rese

ntM

oA

lave

rage

shal

eva

lues

from

Tur

ekia

nan

dW

edep

ohl(

1961

)




TABLE 4


Depth (cm)

Pore water Mo (nM)

Bulk Mo (ppm)

05 1574 11 2 1398 11 4 11 6 2965 10 8 10

10 799 10 12 12 14 1151 10 16 13 18 359 11 20 09 22 30 24 09 26 45 28 10 30 139 10 32 09 34 36 10 38 342 09 40 11 42 144 10 44 10 46 148 11 48 10 50 84 12




















[X]t

D2[X]

z2 [X]

z rxn (4)







korg[org][O2]






TABLE 5














Fig

7D

iage

net

icm

odel

resu

lts

Bas

elin

eva

lues

(red

dot)

are

para

met

ersd

eter

min

edfr

omth

eFO

AM

site

and

are

pres

ente

din

tabl

e5

Un

less

oth

erw

ise

indi

cate

dth

em

odel

sen

siti

vity

anal

yses

use

the

FOA

Mva

lues

for

rele

van

tpar

amet

ers

We

expl

ore

the

sen

siti

vity

ofm

arin

eau

thig

enic

Mo

enri

chm

ents

todi

ssol

ved

seaw

ater

Mo

and

O2s

edim

enta

tion

rate

sor

gan

icm

atte

rra

infl

uxan

dpo

rew

ater

H2S

leve

lsov

era

wid

era

nge

ofpa

ram

eter

spac

ere

leva

ntt

oth

atco

nsi

dere

din

figu

re3



most extreme[Mo]





conclusions








REFERENCES






































































































































Fig

5(A

)D

isso

lved

pore

wat

erFe

con

cen

trat

ion

s(B

)di

thio

nit

eFe

toto

tal

Fera

tios

(Fe d

ithF

e T)

(C)

degr

eeof

pyri

tiza

tion

(DO

P)a

nd

(D)

rati

osof

hig

hly

reac

tive

Feto

tota

lFe

con

cen

trat

ion

s(F

e HRF

e T)

tota

lFe

toA

lrat

ios

(Fe T

Al T

)an

dpy

riti

zed

Feov

erh

igh

lyre

acti

veFe

(Fe p

yFe

HR)

Th

eve

rtic

alba

rre

pres

ents

the

ran

geof

DO

Ppr

evio

usly

mea

sure

dat

FOA

Mfr

omC

anfi

eld

and

oth

ers

(199

2)



discussion






Fig

6Se

dim

enta

ry(A

)M

oco

nce

ntr

atio

ns

(B)

Mo

Alm

assr

atio

s(C

)po

rew

ater

Mo

con

cen

trat

ion

s(D

)se

dim

enta

ryM

nco

nce

ntr

atio

ns

and

(E)

pore

wat

erM

nco

nce

ntr

atio

ns

Hor

izon

tald

ash

edlin

esre

pres

entt

he

dept

hof

sign

ifica

nts

ulfi

deac

cum

ulat

ion

Sh

aded

area

srep

rese

ntM

oA

lave

rage

shal

eva

lues

from

Tur

ekia

nan

dW

edep

ohl(

1961

)




TABLE 4


Depth (cm)

Pore water Mo (nM)

Bulk Mo (ppm)

05 1574 11 2 1398 11 4 11 6 2965 10 8 10

10 799 10 12 12 14 1151 10 16 13 18 359 11 20 09 22 30 24 09 26 45 28 10 30 139 10 32 09 34 36 10 38 342 09 40 11 42 144 10 44 10 46 148 11 48 10 50 84 12




















[X]t

D2[X]

z2 [X]

z rxn (4)







korg[org][O2]






TABLE 5














Fig

7D

iage

net

icm

odel

resu

lts

Bas

elin

eva

lues

(red

dot)

are

para

met

ersd

eter

min

edfr

omth

eFO

AM

site

and

are

pres

ente

din

tabl

e5

Un

less

oth

erw

ise

indi

cate

dth

em

odel

sen

siti

vity

anal

yses

use

the

FOA

Mva

lues

for

rele

van

tpar

amet

ers

We

expl

ore

the

sen

siti

vity

ofm

arin

eau

thig

enic

Mo

enri

chm

ents

todi

ssol

ved

seaw

ater

Mo

and

O2s

edim

enta

tion

rate

sor

gan

icm

atte

rra

infl

uxan

dpo

rew

ater

H2S

leve

lsov

era

wid

era

nge

ofpa

ram

eter

spac

ere

leva

ntt

oth

atco

nsi

dere

din

figu

re3



most extreme[Mo]





conclusions








REFERENCES







































































































































discussion






Fig

6Se

dim

enta

ry(A

)M

oco

nce

ntr

atio

ns

(B)

Mo

Alm

assr

atio

s(C

)po

rew

ater

Mo

con

cen

trat

ion

s(D

)se

dim

enta

ryM

nco

nce

ntr

atio

ns

and

(E)

pore

wat

erM

nco

nce

ntr

atio

ns

Hor

izon

tald

ash

edlin

esre

pres

entt

he

dept

hof

sign

ifica

nts

ulfi

deac

cum

ulat

ion

Sh

aded

area

srep

rese

ntM

oA

lave

rage

shal

eva

lues

from

Tur

ekia

nan

dW

edep

ohl(

1961

)




TABLE 4


Depth (cm)

Pore water Mo (nM)

Bulk Mo (ppm)

05 1574 11 2 1398 11 4 11 6 2965 10 8 10

10 799 10 12 12 14 1151 10 16 13 18 359 11 20 09 22 30 24 09 26 45 28 10 30 139 10 32 09 34 36 10 38 342 09 40 11 42 144 10 44 10 46 148 11 48 10 50 84 12




















[X]t

D2[X]

z2 [X]

z rxn (4)







korg[org][O2]






TABLE 5














Fig

7D

iage

net

icm

odel

resu

lts

Bas

elin

eva

lues

(red

dot)

are

para

met

ersd

eter

min

edfr

omth

eFO

AM

site

and

are

pres

ente

din

tabl

e5

Un

less

oth

erw

ise

indi

cate

dth

em

odel

sen

siti

vity

anal

yses

use

the

FOA

Mva

lues

for

rele

van

tpar

amet

ers

We

expl

ore

the

sen

siti

vity

ofm

arin

eau

thig

enic

Mo

enri

chm

ents

todi

ssol

ved

seaw

ater

Mo

and

O2s

edim

enta

tion

rate

sor

gan

icm

atte

rra

infl

uxan

dpo

rew

ater

H2S

leve

lsov

era

wid

era

nge

ofpa

ram

eter

spac

ere

leva

ntt

oth

atco

nsi

dere

din

figu

re3



most extreme[Mo]





conclusions








REFERENCES






































































































































Fig

6Se

dim

enta

ry(A

)M

oco

nce

ntr

atio

ns

(B)

Mo

Alm

assr

atio

s(C

)po

rew

ater

Mo

con

cen

trat

ion

s(D

)se

dim

enta

ryM

nco

nce

ntr

atio

ns

and

(E)

pore

wat

erM

nco

nce

ntr

atio

ns

Hor

izon

tald

ash

edlin

esre

pres

entt

he

dept

hof

sign

ifica

nts

ulfi

deac

cum

ulat

ion

Sh

aded

area

srep

rese

ntM

oA

lave

rage

shal

eva

lues

from

Tur

ekia

nan

dW

edep

ohl(

1961

)




TABLE 4


Depth (cm)

Pore water Mo (nM)

Bulk Mo (ppm)

05 1574 11 2 1398 11 4 11 6 2965 10 8 10

10 799 10 12 12 14 1151 10 16 13 18 359 11 20 09 22 30 24 09 26 45 28 10 30 139 10 32 09 34 36 10 38 342 09 40 11 42 144 10 44 10 46 148 11 48 10 50 84 12




















[X]t

D2[X]

z2 [X]

z rxn (4)







korg[org][O2]






TABLE 5














Fig

7D

iage

net

icm

odel

resu

lts

Bas

elin

eva

lues

(red

dot)

are

para

met

ersd

eter

min

edfr

omth

eFO

AM

site

and

are

pres

ente

din

tabl

e5

Un

less

oth

erw

ise

indi

cate

dth

em

odel

sen

siti

vity

anal

yses

use

the

FOA

Mva

lues

for

rele

van

tpar

amet

ers

We

expl

ore

the

sen

siti

vity

ofm

arin

eau

thig

enic

Mo

enri

chm

ents

todi

ssol

ved

seaw

ater

Mo

and

O2s

edim

enta

tion

rate

sor

gan

icm

atte

rra

infl

uxan

dpo

rew

ater

H2S

leve

lsov

era

wid

era

nge

ofpa

ram

eter

spac

ere

leva

ntt

oth

atco

nsi

dere

din

figu

re3



most extreme[Mo]





conclusions








REFERENCES








































































































































TABLE 4


Depth (cm)

Pore water Mo (nM)

Bulk Mo (ppm)

05 1574 11 2 1398 11 4 11 6 2965 10 8 10

10 799 10 12 12 14 1151 10 16 13 18 359 11 20 09 22 30 24 09 26 45 28 10 30 139 10 32 09 34 36 10 38 342 09 40 11 42 144 10 44 10 46 148 11 48 10 50 84 12




















[X]t

D2[X]

z2 [X]

z rxn (4)







korg[org][O2]






TABLE 5














Fig

7D

iage

net

icm

odel

resu

lts

Bas

elin

eva

lues

(red

dot)

are

para

met

ersd

eter

min

edfr

omth

eFO

AM

site

and

are

pres

ente

din

tabl

e5

Un

less

oth

erw

ise

indi

cate

dth

em

odel

sen

siti

vity

anal

yses

use

the

FOA

Mva

lues

for

rele

van

tpar

amet

ers

We

expl

ore

the

sen

siti

vity

ofm

arin

eau

thig

enic

Mo

enri

chm

ents

todi

ssol

ved

seaw

ater

Mo

and

O2s

edim

enta

tion

rate

sor

gan

icm

atte

rra

infl

uxan

dpo

rew

ater

H2S

leve

lsov

era

wid

era

nge

ofpa

ram

eter

spac

ere

leva

ntt

oth

atco

nsi

dere

din

figu

re3



most extreme[Mo]





conclusions








REFERENCES























































































































































[X]t

D2[X]

z2 [X]

z rxn (4)







korg[org][O2]






TABLE 5














Fig

7D

iage

net

icm

odel

resu

lts

Bas

elin

eva

lues

(red

dot)

are

para

met

ersd

eter

min

edfr

omth

eFO

AM

site

and

are

pres

ente

din

tabl

e5

Un

less

oth

erw

ise

indi

cate

dth

em

odel

sen

siti

vity

anal

yses

use

the

FOA

Mva

lues

for

rele

van

tpar

amet

ers

We

expl

ore

the

sen

siti

vity

ofm

arin

eau

thig

enic

Mo

enri

chm

ents

todi

ssol

ved

seaw

ater

Mo

and

O2s

edim

enta

tion

rate

sor

gan

icm

atte

rra

infl

uxan

dpo

rew

ater

H2S

leve

lsov

era

wid

era

nge

ofpa

ram

eter

spac

ere

leva

ntt

oth

atco

nsi

dere

din

figu

re3



most extreme[Mo]





conclusions








REFERENCES


















































































































































[X]t

D2[X]

z2 [X]

z rxn (4)







korg[org][O2]






TABLE 5














Fig

7D

iage

net

icm

odel

resu

lts

Bas

elin

eva

lues

(red

dot)

are

para

met

ersd

eter

min

edfr

omth

eFO

AM

site

and

are

pres

ente

din

tabl

e5

Un

less

oth

erw

ise

indi

cate

dth

em

odel

sen

siti

vity

anal

yses

use

the

FOA

Mva

lues

for

rele

van

tpar

amet

ers

We

expl

ore

the

sen

siti

vity

ofm

arin

eau

thig

enic

Mo

enri

chm

ents

todi

ssol

ved

seaw

ater

Mo

and

O2s

edim

enta

tion

rate

sor

gan

icm

atte

rra

infl

uxan

dpo

rew

ater

H2S

leve

lsov

era

wid

era

nge

ofpa

ram

eter

spac

ere

leva

ntt

oth

atco

nsi

dere

din

figu

re3



most extreme[Mo]





conclusions








REFERENCES













































































































































[X]t

D2[X]

z2 [X]

z rxn (4)







korg[org][O2]






TABLE 5














Fig

7D

iage

net

icm

odel

resu

lts

Bas

elin

eva

lues

(red

dot)

are

para

met

ersd

eter

min

edfr

omth

eFO

AM

site

and

are

pres

ente

din

tabl

e5

Un

less

oth

erw

ise

indi

cate

dth

em

odel

sen

siti

vity

anal

yses

use

the

FOA

Mva

lues

for

rele

van

tpar

amet

ers

We

expl

ore

the

sen

siti

vity

ofm

arin

eau

thig

enic

Mo

enri

chm

ents

todi

ssol

ved

seaw

ater

Mo

and

O2s

edim

enta

tion

rate

sor

gan

icm

atte

rra

infl

uxan

dpo

rew

ater

H2S

leve

lsov

era

wid

era

nge

ofpa

ram

eter

spac

ere

leva

ntt

oth

atco

nsi

dere

din

figu

re3



most extreme[Mo]





conclusions








REFERENCES










































































































































korg[org][O2]






TABLE 5














Fig

7D

iage

net

icm

odel

resu

lts

Bas

elin

eva

lues

(red

dot)

are

para

met

ersd

eter

min

edfr

omth

eFO

AM

site

and

are

pres

ente

din

tabl

e5

Un

less

oth

erw

ise

indi

cate

dth

em

odel

sen

siti

vity

anal

yses

use

the

FOA

Mva

lues

for

rele

van

tpar

amet

ers

We

expl

ore

the

sen

siti

vity

ofm

arin

eau

thig

enic

Mo

enri

chm

ents

todi

ssol

ved

seaw

ater

Mo

and

O2s

edim

enta

tion

rate

sor

gan

icm

atte

rra

infl

uxan

dpo

rew

ater

H2S

leve

lsov

era

wid

era

nge

ofpa

ram

eter

spac

ere

leva

ntt

oth

atco

nsi

dere

din

figu

re3



most extreme[Mo]





conclusions








REFERENCES






































































































































Fig

7D

iage

net

icm

odel

resu

lts

Bas

elin

eva

lues

(red

dot)

are

para

met

ersd

eter

min

edfr

omth

eFO

AM

site

and

are

pres

ente

din

tabl

e5

Un

less

oth

erw

ise

indi

cate

dth

em

odel

sen

siti

vity

anal

yses

use

the

FOA

Mva

lues

for

rele

van

tpar

amet

ers

We

expl

ore

the

sen

siti

vity

ofm

arin

eau

thig

enic

Mo

enri

chm

ents

todi

ssol

ved

seaw

ater

Mo

and

O2s

edim

enta

tion

rate

sor

gan

icm

atte

rra

infl

uxan

dpo

rew

ater

H2S

leve

lsov

era

wid

era

nge

ofpa

ram

eter

spac

ere

leva

ntt

oth

atco

nsi

dere

din

figu

re3



most extreme[Mo]





conclusions








REFERENCES







































































































































most extreme[Mo]





conclusions








REFERENCES






































































































































conclusions








REFERENCES









































































































































REFERENCES


























































































































































































































































































































































































































































Documents

An evaluation of sedimentary molybdenum and iron as proxies for …myweb.fsu.edu/jdowens/Publications/Hardisty_2018.pdf · 2018. 7. 26. · Key words: paleoredox, iron speciation,