9. MIOCENE DISSOLUTION FACIES AND ... - Deep Sea Drilling

9. MIOCENE DISSOLUTION FACIES AND MICROFACIES AT NORTHWEST ATLANTIC DEEPSEA DRILLING PROJECT SITE 6031

Elisabeth Gervais, Instituut voor Aardwetenschappen, Vrije Universiteit, Amsterdam2

ABSTRACT

Depth fluctuations of the lysocline and calcite compensation depth (CCD) through time were investigated at DeepSea Drilling Project Site 603, Leg 93. The CCD fell during the middle Miocene at the onset of the Western BoundaryUndercurrent, correlated with seismic Horizon X. Subsequently deposited units show fluctuations of the dissolutioncurve. Major changes in dissolution facies correspond with lithologic boundaries.

INTRODUCTION

Middle Miocene to early Pliocene sediment samplesfrom DSDP Site 603, Leg 93 (Fig. 1) consist of hemipe-lagic clay and claystone (Blake Ridge Formation) andcontain calcareous foraminifers. The preservation of theseforaminifers decreases downward in the section, and be-low the middle Miocene sediments no carbonates are pres-ent. Using the calcite compensation depth (CCD) curveof Tucholke and Vogt (1979, p. 796, fig. 3), which isbased on the back-tracking of several DSDP sites, andadding half the sediment fill to the present water depth(4633 m), Site 603 should have risen above the CCD inthe middle Miocene.

The objective of this study is to investigate the natureand rate of the change from a depositional environmentbelow the CCD to one above the lysocline, through thetransitional environment between the CCD and the ly-socline.

The dissolution of foraminifers has been successfullyused to indicate depth changes of the foraminiferal lyso-cline and CCD. Berger and von Rad (1972) recognizedseveral stages of dissolution ("dissolution facies") basedon calcareous planktonic/benthic foraminifer ratio, per-centage of foraminiferal fragments, percentage of disso-lution-resistant foraminifers, and diversity; they gave eachstage a code ("FS number"), as specified in Table 1. FSnumber 3 roughly equates to lysocline depth; all highernumbers signify a dissolution facies between the lyso-cline and the CCD. Berger (1979) gave an overview ofthe principles and applications of this method.

This FS measure is used in this study of the forami-niferal lysocline and CCD movements at DSDP Site 603,Leg 93.

METHODS

Berger and von Rad (1972) give 10 states of preservation (FS num-bers) for pelagic sediments (Table 1). The dissolution facies of all sam-ples were determined by counting the whole and/or fragmented plank-

1 van Hinte, J. E., Wise, S. W., Jr., et al., Init. Repts. DSDP, 93: Washington (U.S.Govt. Printing Office).

2 Address: Instituut voor Aardwetenschappen, Vrije Universiteit, P.O. Box 7161, 1007MC Amsterdam, The Netherlands.

tonic and benthic foraminifers; estimating the percentage of forami-niferal fragments in a representative split of the residue; and thencalculating the percentage of planktonic to total foraminiferal faunaand the percentage of resistant planktonic foraminiferal forms (Table2). It is noted that FS numbers are influenced by introduction of dis-placed (possibly contemporaneous) and reworked (certainly older) for-aminifers; generally these factors produce lower FS numbers. Displacedsediments are defined by washed residues containing 3% quartz,Quinqueloculina sp., reworked Cretaceous foraminifers, > 9 5 % rockfragments (predominantly silt), echinoid, ostracode, and shell frag-ments, and glauconite, or a combination of these components. Thepercentages of foraminifers were calculated from the fraction between125 and 250 µm.

A total of 161 samples was analyzed. To prevent fragmentation ofcalcareous foraminifers in sample preparation, the samples were soakedin a soda solution until the sediments (clays) disintegrated and thenwere carefully washed in a weak stream of water. More intensely lithi-fied samples of Core 25 and Cores 42 to 54 (with the exception ofSamples 603-42-1, 30-34 cm and 603-46-1, 30-34 cm) required soak-ing in both a soda and a 5% peroxide solution prior to washing.

Table 3 shows estimated percentages of the washed residue compo-nents of the core samples. The solution susceptibility list of plankton-ic foraminifers given by Hemleben and Auras (1984) was used (Table 4),and species with a solution susceptibility 5 are considered resistant.Similar to findings of Hemleben and Auras (1984) on Miocene andPliocene material from the Central Atlantic, Globigerinoides conglo-batus has undergone secondary calcification in all the Hole 603 sam-ples and has therefore become more resistant to dissolution.

RESULTS

The sediment of Cores 54 to 46 was deposited belowthe CCD, and the sample residues only contain sporad-ic agglutinated foraminifers and large amounts of silt(>95%). In and above Core 45, the dissolution curvefluctuates between the CCD and the lysocline (FS num-bers 3-10, Fig. 2). The first minor fluctuations are pres-ent between Cores 45 and 42. In sediment samples be-tween Cores 41 and 36 (with the exception of reworkedsediments of Samples 603-41-3, 30-34 cm and 603-41-6,30-34 cm), absence of calcareous foraminifers and theirfragments points to a return to a depositional environ-ment below the CCD.

The first substantial fluctuations between the CCDand the lysocline are present between Cores 36 and 32,followed by an interval of minor fluctuations betweenCores 31 and 25. Samples 603-25-1, 30-32 cm; 603-25-2,30-32 cm, and 603-25-6, 30-32 cm contain reworked Cre-taceous foraminifers (Table 2). A second interval of sub-stantial fluctuations has been found in Core 24 to the

511

E. GERVAIS

45°N

40c

I 1 I I I I I I I I

DSDP SitesLegs 2,11, 43, 44, 76, 93

85° W

Figure 1. Main physiographic features of the northwestern Atlantic and location of DSDP Sites from Legs 2, 11,43, 44, 76, and 93. DSDP Site 603 of Leg 93 was drilled on the lower continental rise.

lower part of Core 22, followed by minor fluctuations inthe upper part of Core 22 to Cores 21 and 20.

In the intervals with minor fluctuations, a few sam-ples contain flattened foraminifers (Samples 603-22-6,30-34 cm; 603-26-5, 32-36 cm; 603-29-3, 30-34 cm;603-29-4, 30-34 cm, and 603-31-1, 37-39 cm). The fau-na of Cores 19 to 13 commonly contains displaced ele-ments; these sediments have been deposited above theCCD, with the exception of Sample 603-17-2, 30-34 cm.

All residues of Core 16 and Sample 603-17-1, 30-34 cmcontain little or no rock fragments and no bassanite (sul-fate), in contrast to those above and below these sam-ples. Samples 603-18-1, 30-34 cm, 603-19-2, 30-34 cm,603-19-5, 30-34 cm and 603-19-6, 30-34 cm, contain re-worked Cretaceous foraminifers: Globigerinelloides sp.,Heterohelix sp., and Globotruncana sp.

The relatively low percentages of resistant planktonicforaminifers in Cores 17 to 13 is due to a decrease in dis-

512

MIOCENE DISSOLUTION FACIES, SITE 603

Table 1. Calcium carbonate solution facies based on calcareous fora-

minifers, from Berger and von Rad (1972).

FSnumber

1

2

3

4

5

6

7

8

9X

Criteria

Foraminifers undissolved (aragonitic pteropodspresent)

Hastigerina present; many globigerinids bearspines; R < 5%

More spined than nonspined species; 5% < R< 25%

Maximum equitability of assemblage; 25% < R< 50%

Solution obvious; whole tests > fragments;R > 50%

Fragments > whole tests; planktonic wholetests > calcareous benthics f.

Calcareous benthics > planktonics (planktonicsΦ 0)

No whole planktonics; calcareous benthicspresent

Fragments of calcareous foraminifers onlyNo calcareous fragments

Approximateloss(%)

0

- 1 0

<50

50-80

80-90

>90

>95

>98

>99100

Note: The resistant forms (R) are species with a solution susceptibility > 5(rank factors of the planktonic foraminifers are after Hemleben and Au-ras, 1984). In samples from Cores 603-17 to -13, the initial R is smaller be-cause of abundant Globigerina quinqueloba and G. juvenilis/glutinata.

solution and the abundance of globigerinids (Globigeri-na quinqueloba and G. glutinata/juvenilis) in the assem-blage.

Most of the samples contain the sulfate bassanite(2CaSO4 lH2O; determined by X-ray analysis) varyingfrom 0.1 to 28.0% of the wash residue. The bassanitecrystals are often encrusted with very small calcite crys-tals. The large amounts of pyrite (up to 98.5% in thewash residue), with the availability of organic matter(i.e., plant remains) and sulfate (bassanite), may be theend product of bacterial sulfate reduction.

BIOHORIZONS AND RELATIVE DATING

Three planktonic foraminiferal biozones are distin-guished in Cores 54 to 13 of Hole 603. In terms of thestandard zonation of Stainforth et al. (1975), the bio-zones are: the Globorotalia margaritae Zone, the Neo-globoquadrina acostaensis Zone, and the combined Glo-borotalia siakensis-Globorotalia menardii Zone.

The G. margaritae Zone is based on the first appear-ance of Globorotalia margaritae Bolli and Bermudez inCore 19, and the absence of Globorotalia crassaformisGalloway and Wissler and the presence of Globigerinanepenthes Todd in Core 13. The base of the N. acosta-ensis Zone is defined by the first appearance of Neo-globoquadrina acostaensis (Blow) in Sample 603-32-2,94-96 cm and the first appearance of Globorotalia mar-garitae in Core 19. The Globorotalia siakensis and Glo-borotalia menardii Zones cannot be separated becauseof bad preservation or absence of key fossils. Globigeri-na nepenthes has its first appearance in the middle partof the Globorotalia siakensis Zone (Stainforth et al.,1975) and is present (one specimen only) in Core 54 atthe bottom of Hole 603, which implies that this core be-longs to the G. siakensis Zone. However, Core 54 is con-taminated (Site 603 report, this volume), and accordingto the occurrence of nannofossils, the base of the G. sia-

kensis Zone is to be expected between Cores 41 and 51(Muza et al., this volume). Samples of Core 45 containmore specimens of G. nepenthes and are placed in theG. siakensis Zone.

An influx of cold-water fauna marks Sample 603-16-1,30-34 cm (Globigerina bulloides d'Orbigny, Neoglobo-quadrina pachyderma [Ehrenberg], and Neogloboquad-rina atlantica [Berggren]) and is preceded by the entranceof Globorotalia praemiocenica Lamb and Beard in Sam-ple 603-16-2, 30-34 cm and Globigerinoides congloba-tus (Brady) in Sample 603-17-4, 30-34 cm.

DISCUSSION

The major seismic reflections and important litho-logic breaks are conspicuously marked by changes in thedissolution curve (Fig. 2). The Leg 93 scientific party in-terpreted the seismic facies of the interval from Cores 54to 46, which was deposited below the CCD, as distalturbidites. The first fluctuations (Core 45) correspondwith Horizon X, which marks the onset of the present-day Western Boundary Undercurrent (WBUC, see Site603 chapter, this volume). As discussed above, this eventhappened in the middle Miocene. These first minor fluc-tuations at the top of lithologic Unit IC (Cores 45-42)end abruptly in Core 41. This may be the effect of a de-crease of the accumulation rate caused by variations ofthe WBUC contour current and/or a sudden rise in CCDlevel.

The abrupt end of the relatively low CCD level in theinterval between Cores 36 and 32 coincides with seismicreflection Horizon M2. The base of this interval (Core36) coincides with an unnamed seismic boundary. It ispreceded in Core 37 by displaced sediments.

The substantial fluctuations in the interval from Cores23 and 24 do not seem to have been caused by eventsthat also affected the seismic pattern, or do not show onthe seismic record because the zone is too thin and be-yond seismic resolution.

Between Cores 20 and 19, near the base of lithologicUnit IA (reflection Horizon Ml), calcium carbonate iswell preserved. This does not necessarily reflect a dropin CCD level, but can be caused solely by sediment dis-placements (slumps or mud turbidites), resulting in aninflux of shallow-water benthic foraminifers, togetherwith reworked Cretaceous foraminifers (Cores 18 and 19),ostracode and echinoderm fragments, plant remains andglauconite.

The influx of cold-water planktonic foraminifers inSample 603-16-1, 30-34 cm marks the onset of fair pres-ervation of the autochthonous faunal elements. The cal-careous fauna high in the section (Core 16 and above) isgenerally better preserved (FS 6). The time intervalbetween the first emergence of the site above the CCD(Core 45, at approximately 12.0 Ma, in Zone M8) to agenerally better preserved calcareous facies (Core 16, atapproximately 5.4 Ma, at the top of Zone M13) is 6.6 m.y.The Neogene geochronologic time scale of Berggren etal. (1985) is used for this calculation.

The Miocene/Pliocene boundary at this site has beendrawn above Core 16 and does not coincide with a seis-mic sequence boundary. In the subtropical to temperate

513

E. GERVAIS

Table 2. Data concerning the presence and absence of whole and/or fragmented planktonic and benthic foraminifers, the per-centage of foraminiferal fragments, the percentage of planktonic to total foraminiferal fauna, and the percentage of resistantplanktonic foraminiferal forms, Hole 603.

Sample(Core-Section,interval in cm)

13-1, 30-3413-2, 30-3413-3, 30-3413-4, 30-3413-5, 30-3413-6, 30-3414-1, 30-3414-2, 30-3414-3, 30-3414-4, 30-3415-1, 30-3415-2, 30-3415-3, 30-3415-4, 30-3415-5, 30-3415-6, 30-3416-1, 30-3416-2, 30-3416-3, 30-3416-4, 30-3417-1, 30-3417-2, 30-3417-3, 30-3417-4, 30-3417-5, 30-3417-6, 30-3418-1, 30-3419-2, 30-3419-3, 30-3419-4, 30-3419-5, 30-3419-6, 30-3420-1, 30-3420-2, 30-3420-3, 30-3420-4, 30-3420-5, 30-3421-1, 30-3421-2, 30-3421-3, 30-3422-1, 30-3422-2, 30-3422-3, 30-3422-4, 30-3422-5, 30-3422-6, 30-3422-7, 30-3423-1, 30-3423-2, 30-3423-3, 95-9723-4, 30-3424-1, 30-3424-2, 30-3424-3, 30-3424-4, 30-3424-5, 30-3424-6, 30-3424-7, 30-3425-1, 30-3225-2, 30-32

-

ù(63-

250 µm)

PPPPP

PPPPPPPPPPPPPPP

PPPPPPPPPP

P

PX

P

P

P

P

X

car

u(63-

250 µm)

PPPPP

PPPPPPPPPPPPPPP

PPPPPPPPPP

P

PP

P

PP

P

P

P

P

12c

çQ

(63-250 µm)

PPPPP

PPPPPPPPPPPPPPP

PPPPXPPPPP

P

PP

P

X

P

P

nkt

C‰

(63-250 µm)

PPPPP

PPPPPPPPPPPPPPP

PPPPPPPPPP

P

PP

P

PP

P

P

P

s£(125-

250 µm)

69.857.648.451.436.0

Too54.352.685.068.943.244.868.541.869.149.877.774.069.559.661.4

56.352.027.350.0

100.039.034.845.231.037.1

61.6

1(125-

250 µm)

12.858.679.958.695.1

ole

(125-250 µm)

5.876.580.676.592.3

few specimens70.987.092.689.976.068.883.685.177.976.291.488.783.644.792.8

58.390.898.559.850.091.286.774.288.282.9

84.9

85.389.675.983.379.590.670.686.372.882.876.380.371.961.596.9

66.793.499.065.6

96.589.088.292.193.2

78.6Too few specimens

76.594.7

47.168.4 0

Foraminifers present, not determinable

42.9

7.635.7

71.4

100.085.7

75.0

100.0100.0

Too few specimens

12.3

21.4

45.0

96.9

92.9

81.8Foraminifers present, not

98.7

95.5

100.0determinable

(125-250 µm)

50.025.315.231.017.8

29.643.740.241.717.933.349.738.730.426.082.761.863.961.113.3

38.139.120.946.3

32.326.719.421.9

7.5

22.2

33.3

0.70

27.7

16.7

37.5

mi‰

(63-250 µm)

76(4)

36(4)

3

6(4)6663464646666

6(3)10

6(4)6(4)

46944333

1010

6(3)

10107;;

10

1010104

101022

104

103

104

109

but

è(63-

250 µm)

RR

RR

RRRRR

R

RR

R

R

C

CC

C

R

i -o

(63-250 µm)

PP

PP

PP

514

Table 2 (continued).


Sample(Core-Section,interval in cm)

(63-250 µm)

(63-250 µm)

(63- (63-250 µm) 250 µm)

(125- (125- (125- (125-250 µm) 250 µm) 250 µm) 250 µm)

h 0> «

(63- (63- (63-250 µm) 250 µm) 250 µm)

25-3, 30-3225-4, 30-3225-5, 30-3225-6, 30-3225-7, 30-3226-1, 30-3426-2, 22-2626-3, 30-3426-4, 32-3626-5, 32-3626-6, 32-3628-1, 30-3429-1, 30-3429-2, 30-3429-3, 30-3429-4, 30-3429-5, 30-3430-1, 60-6430-2, 60-6430-3, 60-6430-4, 60-6431-1, 37-3931-2, 37-3931-3, 37-3932-1, 55-5732-2, 94-9633-1, 30-3433-2, 30-3433-3, 30-3433-4, 30-3433-5, 30-3433-6, 30-3434-1, 35-3834-2, 35-3834-3, 35-3834-4, 35-3835-1, 30-3335-2, 30-3335-3, 30-3335-4, 30-3335-5, 30-3335-6, 30-3336-1, 28-3236-2, 30-3436-3, 28-3236-4, 28-3237-1, 30-3437-2, 30-3438-1, 30-3438-2, 30-3439-1, 30-3439-2, 30-3440-1, 30-3440-2, 30-3440-3, 30-3440-4, 30-3440-5, 30-3440-6, 30-3441-1, 30-3441-2, 30-34

PPP

P

P

PXP

PPPPPPP

PPPPPPP

100.079.588.9

100.0100.0

77.8100.0100.0

83.8100.0100.0

100.0100.0100.0

32.0

100.097.797.8

100.0100.0

55.6100.0

97.3

99.5Too few specimens

54.5100.029.2

44.371.854.818.252.649.377.5

59.763.517.781.342.336.430.4

72.7

77.1

71.360.9

100.081.863.273.180.0

67.246.295.824.188.5

100.089.9

88.980.0

100.0100.0

0100.0

100.0

100.0

100.0

85.3

82.475.5

100.077.844.294.177.8

77.157.997.545.796.7

100.099.1

100.093.382.4

100.089.5

100.0100.0

68.8

13.5

21.4

11.1

25.981.171.457.162.525.081.3

21.717.410.722.7

3.2

17.6

96699

101010109899

10699

1010999

1010103

1010

6(3)93

104665646

106(3)6(3)

36(3)

2(3)3

10101010101010101C101010

515

E. GERVAIS


Sample(Core-Section,

73

u(63-

•a

ö(63- (63-

3

I(63-

interval in cm) 250 µm) 250 µm) 250 µm) 250 µm)(125- (125- (125- (125- (63- (63- (63-

250 µm) 250 µm) 250 µm) 250 µm) 250 µm) 250 µm) 250 µm)

41-3, 30-3441-4, 30-3441-5, 30-3441-6, 30-3442-1, 30-3442-2, 30-3442-3, 30-3442-4, 30-3442-5, 30-3443-1, 30-3444-1, 30-3444-2, 30-3444-3, 30-3444-4, 30-3445-1, 30-3445-2, 30-3445-3, 30-3445-4, 30-3445-5, 30-3446-1, 30-3446-2, 30-3446-3, 30-3446-4, 30-3448-1, 42-4449-1, 30-3449-2, 30-3449-3, 30-3450-1, 30-3450-2, 30-3450-3, 30-3450-4, 30-3451-1, 30-3451-2, 30-3452-1, 30-3452-2, 30-3452-3, 30-3452-4, 30-3452-5, 30-3453-1, 30-3453-2, 30-3454-1, 30-34

83.050.0

73.366.7

94.7100.0

63.393.3

100.0100.0100.0

100.0

94.4

91.2100.0

75.0100.0

100.0

60.642.1

28.658.3

100.0

58.8

100.0

9101066

101010

6(4)6

109

1010999

10101010101010101010101010101010101010101010109

Note: p = planktonic foraminifers; b = benthic foraminifers; Re = resistant planktonic foraminifers; FS = foraminiferal dissolution code. P =present; R = rare, 0.1-<3.0; C = common, 3.0-<10.0; A = abundant, 10.0-40.0; D = dominant, 40.0-100.0; X: only in fraction< 125 µm. The foraminiferal percentage was calculated for the fractions between 125 and 250 µm. The last two columns show the samples withdisplaced Quinqueloculina sp., a shallow-water benthic foraminifer, and samples with reworked Cretaceous foraminifers.

North Atlantic this boundary does not coincide with thefirst appearance of Globorotalia margaritae (Berggrenet al., 1985), so other indicators or events must be usedto fix this boundary. The influx of cold-water fauna inSample 603-16-1, 30-34 cm (Globigerina bulloides d'Or-bigny, Neogloboquadrina pachyderma [Ehrenberg], andNeogloboquadrina atlantica [Berggren]) is such an event.As noted previously, it is preceded by the entrance ofGloborotalia praemiocenica Lamb and Beard in Sample603-16-2, 30-34 cm and Globigerinoides conglobatus (Bra-dy) in Sample 603-17-4, 30-34 cm.

The first occurrence of G. conglobatus in the sectionprecedes a sudden short rise in CCD level in Sample603-17-2, 30-34 cm. Hemleben and Auras (1984) foundthe same pattern at Site 541 of Leg 78A in the CentralAtlantic, where the first occurrence of G. conglobatuswas found below the Miocene/Pliocene boundary, basedon nannofossils (Bergen, 1984).

Under the assumption that the cold-water sedimentof Sample 603-16-1, 30-34 cm is deposited during thegenerally accepted Messinian cooling period, the Mio-cene/Pliocene boundary of Site 603 may be placed above

516

Core 16. This is in accordance with findings by Moul-lade in Site 604 (this volume), where a sequence of eventssimilar to those at Site 603 occurs: the first appearanceof G. conglobatus, followed by the first appearance ofGloborotalia praemiocenica and the last appearance ofa cold-water planktonic species (Globigerina praebulloi-des). Moullade draws the Miocene/Pliocene boundaryat Site 604 just above the last occurrence of G. praebul-loides (Muza et al., this volume); at Site 603 the Mio-cene/Pliocene boundary can also be drawn between Cores16 and 15, on the basis of nannofossil evidence (Muza etal., this volume).

CONCLUSIONS

The beginning of the fluctuations in the dissolutioncurve coincides with seismic reflection Horizon X, whichmarks the onset of the present WBUC in the middle Mi-ocene.

Major seismic sequence boundaries and importantlithological unit boundaries correlate with fluctuations inthe dissolution curve caused by variations of the WBUCcontour current and/or fluctuations in CCD level.

It has taken Site 603 approximately 6.6 m.y. to risepermanently above the CCD, its sedimentary record po-tentially being a high-resolution monitor of CCD fluc-tuations. Unfortunately, faunal displacement and rework-ing disturb the signal.

The Miocene/Pliocene boundary may be placed aboveCore 16, on the basis of paleontologic and paleoceano-graphic evidence.

ACKNOWLEDGMENTS

I thank Prof. Dr. J. E. van Hinte from the Vrije Universiteit for theinitial idea for this chapter, the material for this study, and for review-


ing the manuscript. I also thank the Leg 93 scientific and technicalparty for sampling and Dr. W. H. Drucker from the University of Am-sterdam for the X-ray analysis.

REFERENCES

Bergen, J. A., 1984. Calcareous nannoplankton from Deep Sea Drill-ing Project Leg 78A: evidence for imbricate underthrusting at theLesser Antillian Active Margin. In Biju-Duval, B., Moore J. C , etal., Init. Repts. DSDP, 78A: Washington (U.S. Govt. Printing Of-fice), 411-445.

Berger, W. H., 1979.' Preservation of Foraminifera: Houston (Soc.Econ. Paleontol. Mineral.), Short Course No. 6:105-155.

Berger, W. H., and von Rad, U., 1972. Cretaceous and Cenozoic sedi-ments from the Atlantic Ocean. In Hayes, D. E., Pimm, A. C , etal., Init. Repts. DSDP, 14: Washington (U.S. Govt. Printing Of-fice), 787-954.

Berggren, W. A., Kent, D. V., and Van Couvering, J. A., 1985. TheNeogene: Part 2. Neogene geochronology and chronostratigraphy.In Snelling, N. J. (Ed.), The Geochronology of the Geological Rec-ord: London (Blackwell Sci. Publ.), Geol. Soc. Mem., 10:211-250.

Blow, W. H., 1969. Late middle Eocene to Recent planktonic forami-niferal biostratigraphy. Proc. 1st. Int. Conf. Planktonic Microfos-sils, Geneva (1967), 1:199-442.

Hemleben, C , and Auras, A., 1984. Variations in the calcite dissolu-tion on the Barbados Ridge complex at Sites 541 and 543, DeepSea Drilling Project Leg 78A. In Biju-Duval, B., Moore J. C , etal., Init. Repts. DSDP, 78A: Washington (U.S. Govt. Printing Of-fice), 471-497.

Stainforth, R. M., Lamb, J. L., Beard, J. H., and Jeffords, R. M.,1975. Cenozoic planktonic foraminiferal zonation and characteris-tics of index forms. Univ. of Kansas, Paleontol. Contrib., Art. 62.

Tucholke B. E., and Vogt P. R., 1979. Western North Atlantic: sedi-mentary evolution and aspects of tectonic history. In Tucholke, B.E., Vogt, P. R., et al., Init. Repts. DSDP, 43: Washington (U.S.Govt. Printing Office), 791-825.

Date of Initial Receipt: 9 April 1985Date of Acceptance: 13 May 1986

517

E. GERVAIS

Table 3. Estimated percentages of washed residue components of samples from Cores 54 to 13 of Hole 603.

Sample(Core-Sectiointerval in ci

ntary rocks (includingclay, silt)

(125-<25Oµm)

(63-<125µm)

(125-;25Oµm)

(63-<125 ur

(125- (63-;250µm) <125µm)

(125-<250µm)

(125-:250µm)

( 6 3 -

< 1 2 5 µ m )(125-

<250µm)(63- (125-

:125µm) <250µm)

13-1, 30-3413-2, 30-3413-3, 30-3413-4, 30-3413-5, 30-3413-6, 30-34

15.015.0

3 7 . 5

2 0 , 0

2 1 , 5

5 6 '

6 0 . 0

3 5 . 06 0 . 05 5 , 09 5 . 0

8 5 . 0

16.019.0

19.012.01 8 . 0

1 4 - 1 , 3 0 - 3 41 4 - 2 , 3 0 - 3 41 4 - 3 , 3 0 - 3 41 4 - 4 , 3 0 - 3 4

4 5 . 0

5 5 . 0

5 5 . 04 9 . 04 0 . 0

4 5 . 0

2 0 111 5 . 04 9 03 7 . 0

1.57.2

4 0 . 01 8 0

2 0 . 04 3 . 0

5 0 . 0

1 8 . 01 0 . 0

4 5 . 01 6 . 0

1 5 - 1 , 3 0 - 3 41 5 - 2 , 3 0 - 3 41 5 - 3 , 3 0 - 3 41 5 - 4 , 3 0 - 3 41 5 - 5 , 3 0 - 3 41 5 - 6 , 3 0 - 3 4

2 3 . 5

2 0 . 0

50.055.075.050.065.0

7 0 . 0

5 0 . 05 0 . 05 0 . 0

d O . l l6 5 . 0

16-1, 30-3416-2, 30-3416-3, 30-3416-4, 30-34

34.070.094.0

1 0 . ( 11 4 . 9

17-1, 30-3417-2, 30-3417-3, 30-3417-4, 30-3417-5, 30-3417-6, 30-34

31.0: 0

93.530.040.0(.0.070.0

.1

5 6 , 05 4 . 05 0 . 05 5 . 07 5 . 04 8 . 5

::; D4 9 . 01 5 . 0

1 0 ;2 1 . 51 5 . 0

1 8 - 1 , 3 0 - 3 4

1 9 - 2 , 3 0 - 3 419-3, 30-3419-4, 30-3419-5, 30-3419-6, 30-34

7 5 . 06 5 , 0

1.0

8 4 . 0

8 0 . 0( . 0 . 050.073.0

4.02 4 . 01 3 . 01 9 . 0

1 5 . 03 7 . 0

1 0 i2 5 . 0

20-1, 30-3420-2, 30-3420-3, 30-3420-4, 30-3420-5, 30-34

22.420.0

4 ( 1 . 51 3 . 026.019.0

55.0XO.O

5 5.070.050.080.0

21-1, 30-3421-2, 30-3421-3, 30-34

41' ii

1 9 . 650.0

90.0

1 0 07 5 . 08 0 . 0

2 2 - 1 , 3 0 - 3 42 2 - 2 , 3 0 - 3 42 2 - 3 , 3 0 - 3 42 2 - 4 , 3 0 - 3 42 2 - 5 , 3 0 - 3 42 2 - 6 , 3 0 - 3 42 2 - 7 , 3 0 - 3 4

5 0 , 02 4 . 0

2 2 . 3

5 0 . 0

1 8 . 02 0 . 04 5 . 52 1 . 0

9 . 03 9 . 04 8 . 0

95.04 5 , 57 5 . 09 0 . 07 0 . 0

7 2 . 57 7 . 05 0 , 04 3 . 0

2 3 - 1 , 3 0 - 3 42 3 - 2 , 3 0 - 3 42 3 - 3 , 9 5 - 9 72 3 - 4 , 3 0 - 3 4

5 5 . 09 4 . 09 5 . 07 4 . 0

8 0 . 091.070.0

24-1, 30-3424-2, 30-3424-3, 30-3424-4, 30-3424-5, 30-3424-6, 30-3424-7, 30-34

1 5 . 03 5 . 0

9 1 . 05 2 . 04 6 , 08 0 . 07 9 . 04 9 . 02 8 . 0

8 6 . 04 0 . 04 5 . 08 5 . 07 8 . 04 0 . 0

2 5 - 1 , 3 0 - 3 22 5 - 2 , 3 0 - 3 22 5 - 3 , 3 0 - 3 22 5 - 4 , 3 0 - 3 22 5 - 5 , 3 0 - 3 22 5 - 6 , 3 0 - 3 22 5 - 7 , 3 0 - 3 2

3 0 . 03 0 . 04 7 . 08 0 . 05 3 . 050.0

6 0 . 02 5 . 043.060.050.0

45.6

7 0 . 06 5 . 05 0 . 01 8 . 0

4 5 . 0

3 9 . 54 7 . 55 0 . 03 5 . 04 7 . 05 0 . 0

9 0 . 0

26-1, 30-3426-2, 22-2626-3, 30-3426-4, 32-3626-5, 32-36

29-1, 30-342 9 - 2 , 3 0 - 3 42 9 - 3 , 3 0 - 3 42 9 - 4 , 3 0 - 3 42 9 - 5 , 3 0 - 3 4

3 8 . 04 9 . 03 0 . 01 5 . 0

3 5 . 2

10.3

55.075.050.095.07 5 . 0

5 3 . 07 0 . 01 9 . 08 6 . 0

6 7 . 0

26-6, 32-36

28-1, 30-34

10.5

23.6

10.3

45.0

5.0 5.0 7 0 . 0

7 5 . 0

5 8 . 0

5 3 . 0

0.1

0.1

0.1

0.1

0.1

0.3

1 6 . 03 4 . 51 5 . 0

5 5 . 05 0 . 06 0 . 07 5 . 0

90 0

5 0 . 06 0 . 06 5 . 06 5 . 07 0 . 0

30-1, 60-6430-2, 60-64

1 2 . 0

1 9 . 5

7 5 . 0

8 0 . 07 7 . 05 0 . 0

Note: =of calc

Tyrare, < 0.1. No: (X-ray analysis)

>r the Other calcareous fossils column that (1) mollusk• found in Sample 603-37-2, 30-34 cm—probably calc

i Samples 603-14-2, 30-34 cm, 603-15-3, 30-34 cm, and 603-19-4, 30-34 cm; (2) unidentified fossils (0.5% in both fractions) made

518



(125- (63- (125- (63- (125- (63- (125- (63- (125- (63- (125- (63- (125-;250µm) <125µm) <25Oµm) < 125 µm) <25Oµm) < 125 µm) <25Oµm) <125µm) <250µm) < 125 µm) <250µm) <125µm) <25Oµm)

(63-: 125 µm)

(125- (63-;250µm) < 125 µm)

4.5 1.70.5 0.4

0.3 0.1

15.0

12.0

3.0

48.310.0

io.n10.015,0

1.0 0.7 0.1 0.3 0.8

0.1

0.1

10.0

3.0

9.5 15.0 0.1

0.50.5

4.012.0

519

E. GERVAIS


•Ms (includinga, clay, silt)

(125- (63-< 2 5 0 µ m ) < 1 2 5 µ m )

(63-:125µm)

( 1 2 5; 2 5 0 µ m )

(63-< 125 µl

(125- (63-<250µm) < 125 µr

(125-;25Oµπ

(63<125 µl

(125-<25O uπ

(63-c 125 µm)

(125-; 2 5 0 µ n

(63-< 125 µm) :250µm) < 125

30-3, 60-6430-4, 60-64

31-1, 37-3931-2, 37-3931-3, 37-39

32-1, 55-5732-2, 94-96

0.90.1

1.512.0

1.6

0.930.5

3.00.2

3.73.06.0

4.10.5

0.220.1

0.14.81.2

24,03.0

7.023.5

0.130.0

4.5

40.02.0

97.079.0

98.078.097.0

50.045.0

85.075.0

95.060.088.0

49.017.0

1.0

0.25.0

25.02.0

5.0

0.1 0 1

0.13.0

0.60.4

0.1

19.0

1.90.3

0.1

17.0

33-1, 30-3433-2, 30-3433-3, 30-3433-4, 30-3433-5, 30-3433-6, 30-34

10.045.034.017.045.0

28.018.023.0

8.045.011.0

79.049.063.083.050.055.0

40.070.090.050.070.0

34-1, 35-3834-2, 35-3834-3, 35-3834-4, 35-38

15.(119.1

75.075.0

50.060.043.0

15.055.0

35-1, 30-3335-2, 30-3335-3, 30-3335-4, 30-3335-5, 30-3335-6, 30-33

20.529.533.0

26.53 1.0

40.017.025.015.0

23.010.0

35 091.050.055.045.035.0

45.065.067.080.(145.040.(1

36-1, 28-3236-2, 30-3436-3, 28-3236-4, 28-32

40-1, 30-3440-2, 30-3440-3, 30-3440-4, 30-3440-5, 30-3440-6, 30-34

11.029.9

36.030.0

97.0 15.0

37-1, 30-3437-2, 30-34

38-1, 30-3438-2, 30-34

39-1, 30-3439-2, 30-34

0.1

0.4

40.0

1.56.5

1.03.0

40.51.0

2.012.0

20.040.0

12.02.0

25.020.0

30.041.0

18.01.4

79.080.0

55.050.0

35.096.0

70.050.0

45.055.0

40.094.0

3.0

24.09.2

12.92.0

•

0.6

0.14.0

0.120.0

0.4

1.414.511.05.05.0

3.02.02.01.5

21.07.0

24.517.0

2.520.0

25.04.0

J2.091.080.055.080.045.0

65.060.029.035.038.065.0

42.015.5

0.085.067.050.090.045.0

74.050.035.040,044.035.0

45.09.5

41-1, 30-3441-2, 30-3441-3, 30-3441-4, 30-3441-5, 30-3441-6, 30-34

25.013.058.030.030.0

42-1, 30-3442-2, 30-3442-3, 30-3442-4, 30-3442-5, 30-34

40.040.278.099.510.0

45.461.496.6

43-1, 30-34

44-1, 30-3444-2, 30-3444-3, 30-3444-4, 30-34

75,0

85,0

40.0

30,0

40.0

35.0 45.065.0

48.00.7

45,050,0

10.06.0

60.0

35.08.0

20.049,0

45-1, 30-34

45-2, 30-34

45-3, 30-34

45-4, 30-34

45-5, 30-34

99,050.0

095,075.015.0

46-1, 30-3446-2, 30-34

46-4, 30-34

48-1,42-44

49-1, 30-3449-2, 30-3449-3, 30-34

97.5

55.0

100.099.999.9

45.0

80.0

100.099.999.9

2.0

0.5

33.0

0.10.1

0.14.0

9.0

0.10.1

2.5

0.5 45.0

50-1.50-2,50-3,50-4,

30-3430-3430-34

•B.'i99.9

100.0100.0

99.9100.0100.0

51-1, 30-3451-2, 30-34

100.0100.0

52 1,52-2,52-3,52-4,5;'•5.

30-3430 3430-3430-3430-34

99.999.999.599.9')9M

99.999.599.9

53-1, 30-3453-2, 30-34

100.099.9 99.5

520



(125- (63- (125- (63- (125- (63- (125- (63- (125- (63- (125- (63- (125- (63- (125- (63-<250µm) <125µm) <250µm) <125µm) <250µm) <125µm) <250µm) <l25µm) <250 µm) < 125 µm) <250µm) <!25µm) <250µm) <125µm) <25Oµm) <!25µm)

0.1

0.5 0.5

2.6

0.40.40.50.1

0.80.5

1.00.1

0.1

4.010.03.02.5

3.43.0

23.01.0

1.51.5

28.0 0.110.0 25.0 23.525.0 25.0 25.02.0 16.0 40.0

10.0 0.1 15.0 17.935.0 40.0 10.015.0 5.0 20.0

S5.035.055.015.5

35.035.0

521

E. GERVAIS

Epochs

Planktonicforaminiferal

zonation

Blow(1969)

Berggrenetal.

(1985)

Stainforthetal.

(1975)

Datums Lithology.y δP .c

Solution faciesby means of FS codes

(Berger and von Rad, 1 9 7 2 )

CCD Lysocline

10 9 8 7 6 5 4 3 2 1T T

275.8

3 0 0 -13

N18 PL1a

15

3 5 0 - Globorotaliamargaritae Globorotalia

praemiocenica

Globigerinoidesconglobatus

Unit IANannofossil-bearingdark grayish green clayto claystone

M13

4 0 0 -

Globorotalia. margaritae

4 5 0 -

N16-N17

17

18

19

21

22

410.2

419.8

M-,-

5 0 0 -M 1 1 -

M12Neogloboquadrina

acostaensis

550-J

24

25 544.6

Figure 2. Diagram of the solution facies of samples from Site 603, Hole 603 of Leg 93, showing foraminiferal dissolution codes (FS codes). The fora-miniferal code values (FS values) represent 10 states of preservation of calcareous foraminifers, given by Berger and von Rad (1972). Washed resi-dues of reworked sediments contain > 3 % quartz, Quinqueloculinα sp., reworked Cretaceous foraminifers, > 9 5 % rock fragments (predomi-nantly silt), echinoid, ostracode, and shell fragments, and glauconite, or a combination of these components. Exact location of M 2 uncertain be-cause of sampling gap.

522


6 0 0 -

6 5 0 -

I3

E

a

0

700

7 5 0 -

8 0 0 -

832.6-

Epochs

Φ

late

oce

lidd

leio

cene

Blow(1969)

N16-N17

?N12-N15

Planktonicforaminiferal

zonation

Berggrenet al.

(1985)

M 1 1 -M12

? M 8 -M10

Stainforthetal.

(1975)

Neogloboquadrinaacostaensis

Globorotaliasiakensis —Globorotalia

menardii

Datums

. Neogloboquadrinaacostaensis

"*~~\ First occurrence

<—I Last occurrence

Φ

oO

26

27

28

29

30

31

32

33

34

35

361

37

38—

39

40

41

42

43

44

45

46

47

ΛO

f O

4 9

50

51

52

53

54

Φ

O

Φ

e

_ πr<Q C/)

> CO

Φ CC ~

Co

re(t

op c

o

|

-_

I

•_

•-__I1•-••1

-J•g

Hi

554.2

563.0

573.4

583.0

592.6

602.2

611.8

621.4

631.0

640.6

1650.2

659.8

669.4

679.0

688.6

698.2

707.8

717.4

727.0

736.6

746.2

755.8

765.4

775.0

784.6

794.2

803.8

823.0

Lithology

Unit IBDark greenish grayquartz-mica bearingclaystone

Unit ICBiogenic silica-bearingclaystone and siltyclaystone

g

Φ <flc cΦ O»- N

IIinΦ

mz

— X -

Solution faciesby means of FS codes

(Berger and von Rad, 1972)

CCD Lysocline

10

r

t.

r•>

8.• •

»

•

t

>o o

§

r

ooo

•

§e8

8

9 8 7 6 5 4_ i—h—f• l I

•

tΛ

m

n—-^•*

n:o•

.:

3 2 1I i

•>

j •

8

O Displaced sediments

• No displaced sediments

o

Figure 2 (continued).

523

E. GERVAIS

Table 4. Solution susceptibility ranking of planktonic foraminifers includingrank factors from delicate (1) to resistant (8), after Hemleben and Auras(1984).

Sediment ranking(this chapter)

Hastigerina pelagicaGlobigerina falconensisGlobigerinella aequilateralisGlobigerinoides ruberG. sacculiferOrbulina universaGlobigerinoides conglobatusGloborotalia inflataG. menardiiG. truncatulinoidesNeogloboquadrina dutertreiG. crassaformisPulleniatina obliquiloculataG. tumidaN. pachydermaSphaeroidinellopsis dehiscens

Rankfactor

1233445556667778

Neogenespecies

Globorotalia praehirsutaG. margaritaeG. miocenicaG. multicamerata

Globigerinoides altispiraGloborotalia tosaensisNeogloboquadrina humerosaNeogloboquadrina acostaensis

Globigerina nepenthes

Sphaeroidinellopsis paenedehiscens

Rankfactor

4444

5666

7

8

Note: Resistant forms = species with a solution susceptibility 5 (this chapter).

524

Documents

9. MIOCENE DISSOLUTION FACIES AND ... - Deep Sea Drilling