Editorial

Quaternary paleoclimatic-paleoceanographic andtectonic evolution of the Marmara Sea and environs

Ali E. Aksu a;�, Cenk Yalt|rak b, Richard N. Hiscott a

a Department of Earth Sciences, Memorial University of Newfoundland, St. John’s, NF, Canada A1B 3X5b Institute of Marine Sciences and Management, Department of Marine Geology and Geophysics, Istanbul University,

Vefa, Istanbul, Turkey

Accepted 19 February 2002

Introduction

‘‘The Euxine Sea formerly did not have its outletat Byzantium, but the rivers which empty into theEuxine forced and opened a passage, and then thewater was discharged into the Propontis and theHellespont’’1

Strabo (63 BC^21 AD; Book 1.3.4; Jones,1954).The Marmara Sea (Fig. 1) has always attracted

interest as a great gateway linking the Black Seato the eastern Mediterranean Sea through a net-work of narrow straits with shallow sills : Straitsof Bosphorus (Istanbul) and Dardanelles(C:anakkale). For the past 2500^3000 yr, informa-tion about surface and bottom currents, depthsoundings and sea-level variation were crucialfor safe navigation across these straits by sea-far-ing people and explorers, thus constituting a ma-jor strategic asset and yielding enormous econom-ic and political advantages. Throughout antiquity,

sailors knew that the bottom waters across theStraits of Dardanelles and Bosphorus £owednorthward, and utilized this knowledge to sailinto the Marmara Sea and Black Sea by loweringlarge baskets with weights into the north-£owingMediterranean water to counteract the strongsouth-directed surface out£ow from the BlackSea.Systematic scienti¢c investigations in the Mar-

mara Sea region started in the late 19th century.The ¢rst bathymetric survey revealed the presenceof three deep basins and their intervening ridges(Andrussow, 1901). P|nar (1943) subsequentlyproposed that a single fault transected these threebasins, extending from the Izmit Bay in the eastto the Gulf of Saros in the west. Pfannensteil(1944) noted the rhombohedric shape of thedeep Marmara Sea basins and proposed that theridges separating the basins represent horst blocksbounded by normal faults. He also suggested, inaddition to the Strait of Bosphorus, the presenceof a second channel, the Sakarya Bosphorus (Fig.1), which connected the Black Sea to the Mar-mara Sea during the Quaternary. In 1948, Ketinpublished his renowned paper revealing the truenature of the North Anatolian fault as one of theworld’s largest active intra-continental strike^slipfaults (Ketin, 1948). Pavoni (1961) and Kopp etal. (1969) proposed that a series of synthetic and

0025-3227 / 02 / $ ^ see front matter H 2002 Elsevier Science B.V. All rights reserved.PII: S 0 0 2 5 - 3 2 2 7 ( 0 2 ) 0 0 3 3 9 - 0

* Corresponding author.E-mail address: aaksu@sparky2.esd.mun.ca (A.E. Aksu).

1 The Euxine Sea is now refered to as the Black Sea, By-zantium as Istanbul, Propontis as Marmara Sea and Helles-pont as Dardanelles.

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antithetic faults are oriented oblique to the east^west trend of the North Anatolian fault zone,determining the structural framework of the Mar-mara Sea. S:engo«r (1979) ¢rst proposed that theevolution of the Marmara Sea must be linked tothe North Anatolian transform fault, situatedalong the northern fringes of the deep Marmarabasins. Detailed bathymetric maps of the Mar-mara Sea became available following the surveyscarried out by the Turkish Navy, Department ofNavigation, Hydrography and Oceanography(T.C. Deniz Kuvvetleri Komutanlig›i Seyir Hi-drogra¢ ve Os:inogra¢ Dairesi) between 1983and 1987, using echo sounder and single-channelseismic re£ection pro¢les.

Tectonic studies

Barka and Kadinsky-Cade (1988) used seismicdata to suggest that the northeast-trending nor-mal faults bounding the ridges between the Mar-mara Sea basins de¢ne a number of strike^slipfaults and that the Marmara Sea is a pull-apartbasin. Ergu«n and Oº zel (1995) and Wong et al.(1995) proposed variations of the pull-apart mod-

el, in which they recognized ¢ve blocks, consistingof three rhombus-shaped basins and two interven-ing transpressional push-up structures, alignedoblique to the North Anatolian transform fault.Straub and Kahle (1994, 1995) and Straub et al.

(1997) used a dense network of GPS sites to de-termine the velocity ¢eld and strain rate pattern atthe western portion of the North Anatolian Faultin the Marmara Sea region and show that Ana-tolia has a horizontal west-directed motion rang-ing from 17 to 24 mm yr31 and that this defor-mation occurs as a narrow belt extending fromthe Gulf of Izmit to the Gulf of Saros (Fig. 1)with a dextral strike^slip motion relative to theBlack Sea. Evans et al. (1985) and Crampin andEvans (1986) used seismological data to show thatlinear patterns of earthquake epicenters outline awedge-shaped block in the area of Marmara Seawhich acts as a separate tectonic unit from therest of western Anatolia. They proposed that theMarmara Sea forms an east^west-trending gra-ben, bounded by two master faults located alongthe northern and southern margins of the deepcentral basins. They further used micro-earth-quake fault plane solutions to show that the Mar-

Fig. 1. Index map of the Marmara Sea and environs. Isobaths are in meters from International Bathymetric Charts of the Medi-terranean, IBCM.

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mara block is being rotated and sheared to ac-commodate the dextral motion of the North Ana-tolian Fault and the extensional tectonics of thewestern Anatolia.Go«kas:an et al. (1997) used high-resolution seis-

mic re£ection pro¢les to suggested that the Bos-phorus represents a tectonically controlled £uvialvalley. Later, Yalt|rak et al. (2000) suggested thatthe Strait of Dardanelles also developed as a £u-vial valley, controlled by the compressional tec-tonics associated with a restraining bend in theNorth Anatolian fault zone.On the basis of land-based geological studies,

Tu«ysu«z et al. (1998) suggested that the Gulf ofSaros is a half-graben, delineated by a dextralstrike^slip fault system at its southern margin.C:ag›atay et al. (1998) interpreted the Gulf of Sarosas a graben de¢ned by normal faults both on thenorthern and southern margins, whereas Yalt|raket al. (1998) suggested that the southern margin ofthe Gulf of Saros is delineated by a dextral strike^slip fault, associated with regional compressionalong the Gelibolu (Gallipoli) Peninsula. Detailedstratigraphy and paleogeography of the Quater-nary deposits in the Gulf of Saros and MarmaraSea are presented by Sak|nc: et al. (1999). Saatc:|laret al. (2000) used multi-channel seismic re£ectiondata to map fault surface-breaks to suggest thatnormal faulting dominates in the north-centralAegean Sea and that this region is in an exten-sional regime. They showed that the amount ofvertical slip on the active normal faults decreasesfrom west to east, and that the fault system cutsthe Aegean Sea in a NE^SW direction, forminghorst and graben.Several recent studies used multi-channel seis-

mic re£ection pro¢les to delineate the tectonic his-tory of the Marmara Sea and environs. Okay etal. (1999) and Parke et al. (1999) showed that thewesternmost Tekirdag› Basin in the Marmara Sea(Fig. 1) is a huge £at-bottomed negative £owerstructure, developed along a releasing bend,bounded in the north by the North AnatolianFault and a number of normal faults in the south.Okay et al. (2000) showed that in the MarmaraSea, the North Anatolian Fault consists of a mainstrand and a few subsidiary branches. The mainstrand includes the Ganos Fault, the Central

Marmara Fault and the North Boundary Fault,which joins with the Izmit segment of the onlandNorth Anatolian Fault. They pointed out that theNorth Boundary Fault is highly oblique to theregional displacement vector, which results inthe generation of a symmetrical fault-wedge basin,the C:|narc|k Basin (Fig. 1). Okay et al. (2000)joined the North Boundary Fault in the west tothe transpressional Central Marmara Fault. Im-ren et al. (2001) concluded that the northern Mar-mara Sea is presently cut by an active continuousstrike^slip fault system which links the onlandportion of the North Anatolian Fault in the eastto the Ganos Fault in the west, with an intricatearray of transtensional and transpressional faults.Kurt et al. (2000) showed that the Gulf of Saros(Fig. 1) formed as a negative £ower structure inresponse to the southward bending of the NorthAnatolian Fault zone in the Plio-Quaternary.They noted two main fault systems in the gulf :a transtensional system bounding the northernand southern margins of the central deep, and aset of normal faults located within the trough.Gu«rbu«z et al. (2000) studied micro-earthquake

focal mechanism solutions and showed that epi-center distribution indicates activity along a sys-tem of pull-apart basins north of the MarmaraSea. The segment between the Marmara Sea andSaros Bay, activated in 1912, and in the Gulf ofIzmit, site of the 1754 earthquake, are now silent.Seismic activity is very linear along the northernbranch of the North Anatolian Fault, but it ismore di¡used on the Bursa and Iznik branches,southeast of the Marmara Sea. Reilinger et al.(2000) also used focal mechanisms and GPS hor-izontal velocities to show that the 1999 Izmitearthquake occurred on a fault segment whichwas previously identi¢ed as a seismic gap, andconcluded that the westward migration of earth-quakes along the North Anatolian Fault contin-ues today.Le Pichon et al. (1999) used earthquake and

GPS data to conclude that the North AnatolianFault in the Marmara Sea constitutes a continu-ous dextral strike^slip segment and predicted thata magnitude 7.6 quake with V4.2 m o¡set wasimminent, somewhere between the locations ofthe 1912 Ganos and 1999 Izmit earthquakes. Tay-

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maz (1999) used teleseismic long-period P- andSH-waveforms to show that faulting that oc-curred during the four largest earthquakes in1999 along the North Anatolian Fault weremainly right-lateral strike^slip in nature and thatslip-partitioning is still taking place on the west-ern segment of the fault zone. Armijo et al. (1999)interpreted the Marmara Sea as a pull-apart witha total extension of 85 km over the past 5 Myr,and pointed out an V2000 km of westward prop-agation of the North Anatolian Fault over thelast 10 Myr.Aksu et al. (2000) used high-resolution single-

channel seismic pro¢les and earthquake data toshow that the Marmara Sea is a large negative£ower structure, bounded by two west-trendingsidewall faults that are linked to a single verticalto steeply south-dipping master fault. They indi-cated that the £ower structure includes detachedbasinal blocks, separated by southwest-trendingridges between the basins, and that these basinsand ridges are rotating counterclockwise to ac-commodate the southward-retreat of the southernsidewall fault.The renewed research interest in the Marmara

Sea and its surroundings over the last few years ismainly caused by the devastating earthquakes ofAugust 17 and November 12, 1999. Consideringthe fact that nearly 25% of the population of theRepublic of Turkey live in the Marmara regionsand that approximately 50% of the Turkish econ-omy is situated in this area, it is clear that anyknowledge leading to a better understanding ofthe tectonic framework of the Marmara Sea andits genetic relationship with the North Anatolianfault is extremely important for Turkey. However,knowledge of the tectonic and kinematic historyof the Marmara Sea is presently in a state of £ux.Although there is widespread agreement that themost recent kinematic history of the Marmara Seamust be linked to the North Anatolian Fault sys-tem the position(s) of the deeply buried fault(s)within the Marmara Sea, the morphotectonics ofthe ridges between the four deep basins, andthe style of faults bounding the deep basins arepresently hotly debated in the literature; thus, alarge number of tectonic and kinematic modelsexist.

Paleoclimatic^paleoceanographic studies

Paleoclimatic and paleoceanographic researchin the Marmara Sea is still in its infancy. Stanleyand Blanpied (1980) used sedimentological dataand radiometric dates from four gravity cores col-lected by the R/V Pillsbury in 1965 to ¢rst suggesta sequence of events describing the water ex-change between the Black Sea and the AegeanSea across the Marmara Sea during the transitionfrom the last glacial to present-day interglacial.They suggested that lacustrine conditions pre-vailed both in the Black Sea and Marmara Seaprior to V12 ka, while the Aegean Sea experi-enced open marine conditions, and that between12 and 9.5 ka large freshwater in£ow into theBlack Sea forced a strong out£ow across theStraits of Bosphorus and Dardanelles. They fur-ther suggested that from 9.5 to 3 ka there was aprogressive decrease in the freshwater out£ow, sothat the two-way water exchange across the straitswas fully established by 3 ka.There was little further paleoclimatic and pale-

oceanographic research in the Marmara Sea untilthe addition of several Turkish vessels to the re-search £eet in the late 70s and early 80s whichprovided much-needed access to marine plat-forms: R/V Sismik-1 (Maden Tetkik Arama Enti-tu«su« , Turkish Geological Survey), R/V Arar (Uni-versity of Istanbul), R/V Bilim (Middle EastTechnical University), R/V Koca Piri Reis (DokuzEylu« l University) and R/V C:ubuklu (TurkishNavy, Department of Navigation, Hydrographyand Oceanography). Several subsequent studiesquanti¢ed the texture, grain size, distribution ofsurface sediments, and sedimentation rates in theMarmara Sea using grab samples (Ergin and Yo«-ru«k, 1990; Ergin et al., 1991, 1992, 1994). Smithet al. (1995) used high-resolution seismic re£ectionpro¢les to show that the level of the Marmara Seaduring the last glacial maximum was 3100 m, andthat the Marmara Sea was isolated at that timefrom the Black Sea and the Aegean Sea by sub-aerially exposed sills at the Bosphorus and Dar-danelles.New research activity in the region has been

sparked by the quest to delineate the role playedby the Straits of Bosphorus and Dardanelles and

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the intervening Marmara Sea in the evolution ofsapropel deposits in the eastern MediterraneanSea. Ryan et al. (1997) used sedimentary dataand radiometric ages from the northern BlackSea shelf to postulate that during the last glacialmaximum, the Black Sea became a giant fresh-water lake, the surface of which stood at 3150m, and that at V7150 yr BP the Mediterraneanrose to breach the sill at the Bosphorus causingsaltwater to catastrophically £ood the Black Seashelves. Ryan and Pitman (1999) linked this£ooding event to Noah’s Flood. Several papershave been published following the Ryan et al.(1997) paper, presenting paleoclimatic and pale-oceanographic arguments for and against the‘Flood Hypothesis’ (Aksu et al., 1999; Demirbag›et al., 1999; Yanko et al., 1999; C:ag›atay et al.,1999, 2000; Ballard et al., 2000; Uchupi andRoss, 2000; Yalt|rak et al., 2000; Go«ru«r et al.,2001; Algan et al., 2001). Ballard et al. (2000)used side-scan sonar data and dredge samples tointerpret the presence of a high-energy beach at155 m water depth in the south-central Black Sea,and used radiocarbon dating of mollusk shellscollected from this ancient beach to infer thatthe marine £ooding of the Black Sea took placebetween 7.46 and 6.82 ka. The also reported well-preserved wood samples recovered from this samelocation which yielded dates as old as 3.58 ka.Uchupi and Ross (2000) used echo-soundingdata recorded in the Black Sea in 1969 to showthe presence of asymmetric bedforms, 5^150 mhigh at a depth of 2000^2200 m, that resemblemigrating sediment waves, and suggested thatthey were deposited during the catastrophic£ooding of the Black Sea from the MarmaraSea at V7.15 ka. Demirbag› et al. (1999) usedhigh-resolution single-channel seismic re£ectionpro¢les from the southwestern Black Sea shelfto suggest that faulting along the Strait of Bos-phorus, rather than sea-level rise, was the primarycause of the sudden £ooding of the Black Seashelf.Aksu et al. (1999) used single-channel seismic

re£ection pro¢les to show the presence of well-developed west-directed bedforms on the westernMarmara Sea shelf beneath a post-glacial surfacemud drape, and suggested that at V9.50 ka the

Black Sea rose to the breach depth of the Bos-phorus and that the brackish water stored in theBlack Sea developed into a vigorous southward£ow toward the Aegean Sea. They further sug-gested that this £ow persisted until V7 ka, afterwhich the mud drape began to accumulate in theMarmara Sea and euryhaline Mediterranean mol-lusks successfully migrated into a progressivelymore saline Black Sea.C:ag›atay et al. (1999, 2000) used sedimentary

data and radiocarbon ages from cores to suggestthat the Marmara Sea was a freshwater lake dur-ing the late glacial to V12 ka, at which time itwas inundated by Mediterranean waters andgradually converted into a marine realm. Theydocumented two sapropel layers, deposited at10.6^6.4 ka and 4.75^3.2 ka under suboxic bot-tom-water conditions. They showed that the oldersapropel is roughly synchronous with the S1 sap-ropel unit of the eastern Mediterranean, and sug-gested that a large in£ux of freshwater from theBlack Sea was an important factor in sapropelformation in the eastern Mediterranean.Algan et al. (2001) used paleontological data

and radiocarbon ages in boreholes to show thata portion of the Strait of Bosphorus remained asa freshwater lake from V26^5.3 ka and that the¢rst appearance of euryhaline Mediterranean fau-na occurred in that former lake at 5.3 ka, with thetwo-way £ow in the strait being established at 4.4ka. Go«ru«r et al. (2001) used sedimentological andseismic stratigraphic data and radiocarbon datesfrom shelf sediments o¡ the Sakarya River inBlack Sea to show that immediately prior to its£ooding by the Mediterranean waters at about 7.2ka, the Black Sea was a freshwater lake, emptyingits waters into the Sea of Marmara, and that thewater level of this lake was about 18 m lower thanthe present sea level, but above the 335 m silldepth of the Bosphorus. Yanko et al. (1999)used stable isotopic data in planktonic andbenthic foraminifera to show that the watermass in the Marmara Sea was strati¢ed since3 ka, with a strong surface out£ow from the BlackSea delineated by persistently depleted oxygen iso-topic values, and a higher salinity bottom in£owof Mediterranean water re£ected in enriched iso-topic values.

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Special issue

This special issue is dedicated to the memoriesof Dr. Ihsan Ketin, one of the fathers of moderngeology in Turkey and Dr. Aykut Barka, Ketin’sformer student and co-worker. We are proud andprivileged to continue their mission to study var-ious aspects of geology in this exciting region.This issue consists of two parts.Part A includes 12 papers which describe vari-

ous aspects of Quaternary paleoceanographic andpaleoclimatic evolution of the Marmara Sea andits immediate surroundings. Major et al. presenthigh-resolution sedimentological and stable iso-topic data from two cores to show that an in-creased supply of meltwater reached the BlackSea at 15 ka, followed by an interval of marineconnection at V12.8 ka. Caner and Alganpresent palynological data to suggest a terrige-nous source for the sapropel in the MarmaraSea. Tolun et al. present organic geochemicaldata for two sapropel/sapropelic layers dated as10.6^6.4 ka and 3.8^3.2 ka, and demonstrate that£ooding of the Marmara Sea by Mediterraneanwaters occurred at V12 ka, and that the onsetof deposition of the lower sapropel was charac-terized by a high in£ux of terrigenous organicmatter whereas there was an increase in marineorganic carbon burial toward the upper sapropeliclayer. Aksu et al. (a) use high-resolution seismicre£ection pro¢les from the southwestern BlackSea to demonstrate that transgressive systemstract deposits, consisting of a set of shingled,shore-parallel, back-stepping parasequences, weredeposited during a phase of relatively rapid sea-level rise, associated with the post-glacial trans-gression spanning V11.5^12.0 ka and that thinveneers of seismically transparent muds show on-lap onto the £anks of older sedimentary features.Hiscott et al. describe two south-prograded deltalobes at the southern exit of the Bosphorus, andshow that the younger delta was active from 10 to9 ka, at a time of accentuated Black Sea out£ow,whereas the oldest delta lobe possibly developedfrom 29.5 to 23.5 ka when Marmara sapropel M2accumulated in deep basins and the Marmara Seastood V55 m lower than today. Aksu et al. (b)use multi-proxy micro-paleontological and stable

isotopic data and radiocarbon ages to show thattwo distinct sapropel beds (M2 and M1) weredeposited in the Marmara Sea from 29.5 to 23.5and 10.5 to 6.0 ka, respectively, during periods oflowered sea-surface temperatures and salinities.Abrajano et al. use organic geochemical data toshow that sapropel M1 is marked by a depletionin the 13C of the water column-dissolved inor-ganic carbon, suggesting strong density strati¢ca-tion in the Marmara Sea. Kaminski et al. docu-ment benthic foraminiferal assemblages in anumber of Marmara Sea cores and show that sa-line waters from the Mediterranean Sea over-topped the Dardanelles sill by V12 ka, left a sig-ni¢cant imprint at the Bosporus exit by V9.5 ka,but were unable to penetrate into the Black Seauntil after 9.1 ka because of the persistent strongout£ow of brackish to fresh water from the BlackSea. Mudie et al. (a) use dino£agellates, fresh-water algae and fungal spores in Marmara Seaand Black Sea cores to show that although glacialstages were marked by much lower sea-surfacetemperatures, there was either some periodic ma-rine in£uence or marine dinocysts were living in abrackish-water environment, with freshwater spe-cies being transported from glacial lakes; there isno palynological evidence that the surface watersof the Black Sea or the Marmara Sea were everfresh during the late Quaternary. Mudie et al. (b)further document ¢ve pollen^spore assemblages incores from the Marmara sea, and use a steppe^forest index to show that the only intervals ofseverely dry conditions occurred brie£y duringthe last glacial maximum and its transition; dur-ing most of the Pleniglacial and all of post-glacialtime precipitation minus evaporation was su⁄-ciently high to permit persistence of oro-Mediter-ranean forest vegetation. Hiscott and Aksu showthe presence of three allostratigraphic units withinthe Quaternary successions of the Marmara andBlack seas, where allounits are bounded by un-conformities and their correlative conformities.Yalt|rak et al. used several U/Th dates from insitu shells collected at four localities of raisedPleistocene coastal deposits from the westernMarmara region to show that the extreme Qua-ternary transgressions occurred during the high-stands of oxygen isotopic stages 7 and 5; they

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calculated a regional uplift rate of V0.4 mm peryr for the Strait of C:anakkale (Dardanelles) sinceV225 ka to account for uplift of these deposits toform terraces.Part B includes 11 papers which describe the

Quaternary tectonic history of the Marmara Seaand environs. Yalt|rak and Alpar show that Gem-lik Bay (Fig. 1) developed as a pull-apart basinduring the late Pliocene^early Pleistocene, associ-ated with the activity of west-trending dextralstrike^slip faults along the middle strand of theNorth Anatolian Fault zone. Alpar and Yalt|raksuggest that Izmit Bay in the northeastern Mar-mara Sea is a negative £ower structure controlledby the northern branch of the North Anatolianfault zone. Yalt|rak and Alpar show that the Ga-nos Fault is genetically related to the North Ana-tolian fault zone and displays a positive £owerstructure on the Gelibolu Peninsula and a nega-tive £ower structure within the Gulf of Saros.Oktay et al. describe the late Quaternary openingof the Strait of Istanbul (Bosphorus) through aclockwise rotation of the Istanbul and Kocaelipeninsulas by right-lateral shearing of the NorthAnatolian fault system, and the development ofNNE^SSW left-lateral faults in the Strait of Istan-bul. Adatepe et al. used gravity modeling andseismic re£ection pro¢les to show that GemlikBay formed under the control of the dextralNorth Anatolian fault with the northwest-trend-ing Thrace^Eskis:ehir fault playing a secondaryrole. Gaziog›lu et al. use multi-beam data toshow that the east^west-trending elliptical Mar-mara Trough, including the four deep basinsand their intervening ridges, is the primary mor-photectonic feature in the Marmara Sea, and thatthe right-lateral displacement of the ridges andbasins re£ects their genetic link with the dextralNorth Anatolian fault system. Kus:c:u et al. docu-ment the presence of an older and mostly inactiveset of faults in the Gulf of Izmit responsible forthe formation of a large pull-apart depression,and a younger active set which cuts through theolder faults. Yalc:iner et al. recognize the slopefailures as a possible trigger for tsunamis in theMarmara Sea using multi-beam and shallow anddeep seismic re£ection data. Papanikolaou et al.use swath bathymetry to show that the overall

geometry and kinematics of the North AegeanBasin are primarily controlled by northeast-trend-ing and to a lesser extend northwest-trendingstructures associated with the North Anatolianfault zone. Yalt|rak shows that the tectonic evo-lution of the Marmara Sea re£ects two periods ofactivity of distinctly di¡erent fault systems: in theMiocene to early Pliocene the tectonic frameworkwas controlled by the Thrace^Eskis:ehir fault,whereas during the post-late Pliocene the NorthAnatolian Fault became connected to the Ganos,Band|rma^Behramkale and Manyas^Edremitfaults. Finally, Leroy et al. use palynological evi-dence to document a sedimentary layer in coresfrom Manyas Lake (Fig. 1) which resulted from aseiche, either through a salt inundation linked to atsunami in the Marmara Sea or as the result of alarge hydrothermal £uid discharge.We anticipate that this special issue will form a

reference manual to guide future studies of theQuaternary tectonic, paleoclimatic and paleocea-nographic evolution of the Marmara Sea Gate-way and its immediate surroundings. Work inthis exciting region will surely continue for yearsto come: several recent cruises will undoubtedlyadd several new pieces to the jigsaw puzzle pro-vided by this important oceanographic gatewayand focal point of micro-plate tectonics.

Acknowledgements

Critical evaluation of the 23 scienti¢c paperspublished in this special volume was no smalltask. We are much indebted to the following 45reviewers for their diligent work, constructivecriticisms, and suggestions which undoubtedly im-proved the manuscripts in this volume: Teo¢lo A.Abrajano, Jr. (Rensselaer Polytechnic Institute) ;Ali E. Aksu (Memorial University of Newfound-land); Christian Beck (Universite¤ de Savoie) ; Er-din Bozkurt (Middle East Technical University) ;Jonathan Bull (University of Southampton); Ma-ria Bianca Cita (Universita' Via Mangiagalli) ; Ro-dolfo Coccioni (Universita’ degli Studi) ; StuartCrampin (University of Edinburgh) Marc De Ba-tist (Universiteit Gent); Kay-Christian Emeis (In-stitute fur Ostseeforschung); Russ Evans (British

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Geological Survey); Claudio Faccenna (Universitadegli Studi Roma); Jiasong Fang (University ofMichigan) ; Eric Fielding (Jet Propulsion Labora-tory); Roger Flood (State University of NewYork); Simone Galeotti (Universita' degli Studidi Urbino); Cem Gaziog›lu (Istanbul University);Jeremy Hall (Memorial University of Newfound-land); Aure¤lia Hubert-Ferrari (Princeton Univer-sity) ; Ian Hutchinson (Simon Fraser University);Phil Kearey (University of Bristol) ; Hermann Ku-drass (Bundesanstalt fu«r Geowissenschaften undRohsto¡e); Suzanne Leroy (Brunel University);Ande¤s Maldonado (Universidad de Granada);Fabienne Marret (University of Wales) ; JensMatthiessen (Alfred Wegener Institute for Polarand Marine Research); Hugh Miller (MemorialUniversity of Newfoundland); Emile A. Okal(Northwestern University) ; Fazl| Y. Oktay (Istan-bul Technical University) ; David J.W. Piper(Geological Survey of Canada); Andre¤ Rochon(Geological Survey of Canada); Yoshiki Saito(Geological Survey of Japan); Jim Silliman (Geo-logical Survey of Canada); Kenneth Skene (MobilOil Canada); Christopher Smart (University ofPlymouth); Costas Synolakis (University ofSouthern California); Tuncay Taymaz (IstanbulTechnical University); Alessandro Tibaldi (Uni-versity of Milan-Bicocca); Alfred Traverse (Hun-tingdon, Pennsylvania); Fabio Trincardi (InstitutoGeologia Marina, Bologna); Robert Twiss (Uni-versity of California at Davis) ; Pieter Van Re-nsbergen (Universiteit Gent); Phil Weaver (Uni-versity of Southampton); Abraham Zelilidis(University of Patras); Karen Zonneveld (Univer-sity of Bremen); Jochen Zschau (GeoForschungsZentrum).

References

Aksu, A.E., Hiscott, R.N., Yas:ar, D., 1999. Oscillating Qua-ternary water levels of the Marmara Sea and vigorous out-£ow into the Aegean Sea from the Marmara Sea^Black Seadrainage corridor. Mar. Geol. 153, 275^302.

Aksu, A.E., Calon, T.J., Hiscott, R.N., Yas:ar, D., 2000. Anat-omy of the North Anatolian fault zone in the Marmara Sea,Western Turkey: Extensional basins above a continentaltransform. GSA Today, June 2000, 3^7.

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