U.S. DEPARTMENT OF THE INTERIOR 

U.S. GEOLOGICAL SURVEY

Holocene Continental Flood Events in marine sediments

of the Gulf of Mexico

R. Z. Poore and L.M. Wright

U.S. Geological Survey, MS 926A 

National Center, Reston VA 20192

Open-File Report 99-566

This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey 

editorial standards (or with the North American Stratigraphic Code). Any use of trade, product, or 

firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
Holocene Continental Flood Events in marine sediments of the Gulf of Mexico

Richard Z. Poore and Liana M. Wright 

U.S. Geological Survey, MS 926-A 

National Center, Reston VA 20192

Introduction

This report contains data and initial interpretations from a reconnaissance study of 

Holocene marine sediments recovered from the Pigmy Basin on the continental slope off 

Louisiana (Fig. 1). The Gulf of Mexico (GOM) is closely linked to and influenced by processes 

and conditions on adjacent continental areas. The Mississippi and other major rivers transport 

large amounts of fresh water and sediment into the GOM. Thus, the marine sediments in the 

GOM contain information on changing conditions within the GOM and on changing conditions 

on the adjacent land areas. Previous studies show that major hydrologic events within the 

Mississippi Basin are recorded in GOM sediments. For example, during the last deglaciation, 

large amounts of meltwater flowed down the Mississippi River resulting in lower surface water 

salinities. The reduced surface water salinities are reflected in anomalously low (light) oxygen 

isotope ratios in the shells of surface dwelling planktic foraminifers that were deposited in the 

GOM at the time of the meltwater event (e.g. Kennett and Shackleton, 1975; Kennett and others, 

1985). The isotopic meltwater signal is largest near the mouth of the Mississippi River, but is 

still evident, albeit subdued, in cores off the coast of Mexico (Kennett and Shackleton, 1975; 

Leventer and others, 1982). In addition to the deglacial meltwater event, data from piston cores 

recovered in the Orca Basin, which is adjacent to the Pigmy Basin, suggest that a series of major

1
continental flood events or prolonged wet periods occurred within the Mississippi Basin during 

the last 5,000 years. The "megafloods" are recorded in Orca Basin sediments by a combination 

of changes in the planktic forarninifer assemblages, carbon isotopic values in surface dwelling 

planktic foraminifers, and increases in the grain size of the siliciclastic mud component of the 

sediments (Brown and others, 1999). Our general purpose in this study is to assess the overall 

potential of the sediments of the Pigmy Basin for developing a detailed record of environmental 

changes in the GOM and specifically to see if the sediments contain evidence for Holocene 

continental flood events.

Materials and Methods

The Pigmy Basin is a narrow intraslope basin on the continental slope off Louisiana (Fig. 

1). The basin is bounded on the northwest and southeast by steep slopes that show signs of 

submarine slides. In 1983, the Ocean Drilling Program drilled two holes, 619 and 619A, near the 

axis of the basin. Hole 619 was continuously cored to 208.7 meters subbottom. The shipboard 

scientific party concluded that the first core of Hole 619 began below the sediment-water 

interface and did not recover the top portion of the sedimentary column. Thus, at the conclusion 

of Hole 619, a single core (619A) was taken to recover the upper portion of the sedimentary 

sequence. Core 619A recovered approximately 5.2 meters of hemipelagic gray mud. The entire 

core shows signs of drilling disturbance; the disturbance is most severe at the top of the core and 

becomes less severe towards the base of the recovered section. The drilling disturbance 

precluded high density sampling. In general, we tried to obtain samples every 10 to 20cm and 

avoid the most severely disturbed intervals. Distribution of samples along with estimated 

abundance of microfossils and selected non-organic sediment constituents and drilling 

disturbance are summarized in Figure 2.

2
Sample processing

Samples for foraminifer and isotope analyses and Accelerator Mass Spectrometry (AMS) 

14C dating were dried at <50°C, disaggregated in deionized water and wet sieved at 63(im. The 

>63(im fraction was dry sieved into 63-150(im and >150(im fractions. All samples were 

screened to estimate abundances of benthic and planktic foraminifers and siliceous microfossils. 

(Fig 2). Abundances were estimated on an arbitrary scale. Constituents with one or two 

individuals per sample were termed "trace"; constituents that appeared to compose over 50% of 

the sample were termed "abundant". "Rare" and "common" were gradations between the two 

endpoints.

Chronology

Three samples from the least disturbed area of the 619A were selected for AMS 14C 

dating. The dates were obtained on mixed planktic foraminifers hand picked from the >150jo,m 

washed residue. The picked specimens were cleaned in an ultrasonic bath to remove any fine 

sediment and other debris in sutures and apertures. The carbon from these samples was first 

captured as CO2 by acidification of the entire sample with 85% phosphoric acid (H2PO4) in a 

vacuum chamber. The CO2 was then dried by forcing the gas through a water trap cooled to 

approximately 80°C. The dried CO2 was converted to pure carbon in the form of graphite by 

placing a measured volume (equivalent to 1 mg carbon) in a chamber with iron powder, 

hydrogen, and zinc as a catalyst at 575°C for ten hours. The sample carbon (precipitated on the 

iron) was pressed into aluminum targets for AMS analysis. Dating was done at the Lawrence 

Livermore Laboratory Center for Accelerator Mass Spectrometry (CAMS) in Livermore, CA 

(see Roberts, M. L., and others, 1997, for a detailed description of the CAMS facility and

3
operation. AMS 14C dates are corrected by 400 years for reservoir effects, (Brown and others, 

1999). An age model for the core was constructed by assuming constant accumulation rates 

between AMS 14C dates (Table 1) and a modern age for the core top.

Stable isotopes

We obtained oxygen and carbon isotope values for Globigerinoides ruber (white variety) 

and G. sacculifer from all samples that contained enough material for analyses. In general, we 

analyzed 5 specimens of G. ruber from the 212-250|im fraction and 5 specimens of G. sacculifer 

from the 250 - 350 \\m fraction. Isotopic measurements were done using the Woods Hole 

Oceanographic Institution Finnigan MAT252 mass spectrometer equipped with a "Kiel" 

automated carbonate analytical device containing two parallel extraction lines. The system is 

designed to analyze each sample in a separate reaction vessel, which is placed on the vacuum 

system for the 10 minute reaction with 70°C, 100% phosphoric acid made using a modified 

Coplen and others (1983) formula. During the ten minute reaction time, all evolved gases are 

trapped at liquid nitrogen temperatures. When the reaction is over, the non-condensables are 

pumped away and the first trap is warmed to -100°C, releasing the CO2 , but trapping the water. 

The pressure of evolved CO2 is measured and recorded and the second trap temperature is 

lowered to -190°C. At the end of the CO2 transfer from the first trap to the second, the second 

trap is warmed to room temperature and the gas is introduced into the mass spectrometer through 

a capillary and expanded if necessary. All traps are baked at +130°C after each reaction to 

remove contaminating water vapor.

Isotopic values are reported relative to Vienna Pee Dee Belemnite (VPDB) in delta 

notation and expressed in per mil using the intermediate standard NBS 19. The precision of

4
2,200 NBS 19 analyses run during the interval between March 1993 and June 1998 (all sizes 

from 10 to 300 |Lig) is 0.07 for 818O and 0.03 for 813C. Small sample (10-20 |Lig and under, all 

laboratory conditions) precision is 0.14 for 818O and 0.06 for 813C. Since standard material is 

weighed, we use the relationship between weight and voltage of standard material to assess 

unknown data based upon its mass 44 voltage. We only accept data which has a mass 44 sample 

voltage greater than 0.6 volts and whose ratio between sample and standard voltage (efficiency 

of bellows balancing) is between 0.8 and 1. Isotopic data from our samples are listed in Table 2.

Planktic foraminifer census

A census of the planktic foraminifer assemblage >150|Lim was obtained for samples 

below Section 1 that had common planktic foraminifers (see Fig 2 and Table 3). Samples from 

Section 1 had sparse planktic assemblages and were from highly disturbed areas of the core. The 

washed residues (>150|4,m) were mechanically split to obtain a sub-sample of ~ 300 planktic 

foraminifers for the faunal census. Individual specimens were identified and counted on 

standard 60 square microfossil slides. We follow the taxonomy of Parker (1962) as modified by 

Poore, (1979). Census results are in Table 3. List of taxa in Table 3 are in the taxonomic notes 

section.

Results

Our isotopic and faunal data from the Pigmy Basin suggest changes in average sea 

surface temperature conditions in the GOM during the Holocene and also show evidence for 

several Holocene flood events (Fig. 3). The 818O value in planktic foraminifers generally reflects 

the temperature and the isotopic composition of the sea water in which the foraminifer forms its 

shell. Colder temperatures result in more positive (heavier) 818O values whereas warmer

5
temperatures result in more negative (lighter) 818O. On glacial - interglacial time-scales, the 

overall isotopic composition of the ocean water reflects the amount of freshwater stored on the 

continents as ice. More continental ice volume results in more positive sea water 818O while less 

continental ice results in more negative sea water 818O. Variations in the input of freshwater to 

marine waters also affects the isotopic values of sea water since freshwater has more negative 

818O and 813C than sea water.

Globigerinoides ruber (white variety) is a surface dwelling form that tends to live yearround in the GOM (Flower and Kennett, 1990) and is a good recorder of average annual 

temperature. Globigerinoides ruber is also more euryhaline than other planktic foraminifers and 

thus remains near the surface even when salinity is reduced (see discussion in Flower and 

Kennett, 1990). Globigerinoides sacculifer is a surface dwelling form that yields isotopic values 

that are more positive than G. ruber throughout our record at 619A (Fig 3). In the GOM, G. 

sacculifer is most common in sediments underlying the loop current that brings open marine 

tropical surface waters into the GOM. The more positive 818O of G. sacculifer with respect to G 

ruber in our data set from 619A indicates that G. sacculifer lives slightly deeper in the water 

column or is more abundant during the winter months, thus accounting for the more positive 

isotopic values.

The 818O plots for G. ruber and G. sacculifer and faunal abundance data (Fig 3) show a 

general three fold division of the Holocene. In the earliest part of the Holocene, both taxa show 

more positive values, indicating cooler surface water conditions. The middle part of the 

Holocene, from about 7 to 2 kya has more negative (although variable) 818O values in both taxa 

indicating overall warmer surface waters with the warmest intervals being between about 2.0 to 

2.5 kya and 4.5 to 6.5 kya. The youngest part of the Holocene shows a trend towards cooler

6
temperatures as evidenced by the more positive isotopic values. The faunal census data supports 

the temperature changes suggested by the isotopic trends. In the GOM, Globorotalia 

crassaformis is considered a cool water indicator (Kennett and others, 1985). Neogloboquadrina 

pachyderma (right-coiling) is a sub-polar North Atlantic form (Kipp, 1976) and 

Neogloboquadrina "dupac", an informal taxon representing specimens transitional between 

right-coiling Neogloboquadrina pachyderma and N. dutertrei , is primarily a sub-polar North 

Atlantic form (Kipp, 1976). Note that the sub-polar representatives of Neogloboquadrina and 

the cool water G. crassaformis are present in the oldest part of the Holocene record, but are 

absent from the samples between 4.5 and 6.5 kya that show more negative isotopic values and, 

hence, wanner temperatures. The interval between 4.5 and 6.5 kya also has the highest percent 

of the G. sacculifer, which is indicative of higher temperatures or stronger influence of the 

tropical loop current. Globorotalia crassaformis reappears in samples between 2.5 and 3.5 kya 

when isotope values become more positive, but not as positive as the values at the beginning of 

the Holocene. Aside from two minor occurrences, the sub-polar species are absent from 

assemblages between 2.5 and 3.5 kya, thus supporting the interpretation of somewhat cooler 

temperatures, but not as cool as the early Holocene interval. The temperature trends indicated by 

the isotopic data in 619A are consistent with a number of studies that suggest that the middle part 

of the Holocene was the wannest interval of the last 10,000 years (e.g. see discussion in Dwyer 

and others, 1996).

Two anomalous excursions to negative values below - 2.3 per mil occur in the G. ruber 

818O record between 7 and 8 kya. The 818O excursions stand out from the rest of the G ruber 

818O data, which generally have values more positive than about -1.9 per mil. In addition, the 

two excursions in 818O are accompanied by negative excursions in the 813C record (Fig. 3). We

7
interpret the strong negative excursions in both 818O and 813C as evidence for floodwater events 

that caused a low salinity surface water layer with negative 818O and 813C isotopic values to 

develop in the Pigmy Basin area. We do not believe the prominent excursions in the G. ruber 

isotopic values between 7 and 8 kya are temperature events because the G. sacculifer 818O record 

does not show indications of a significant temperature change at these levels and a temperature 

increase would not explain the negative excursion in the G. ruber 813C. Since our samples span ~ 

2cm of core, the samples average at least 40 to 50 years of time. Thus, we cannot determine if 

the excursions represent one large event or a series of events occurring over a multiyear period. 

The development of a thin (ca <50m) low salinity surface layer best explains the isotopic data. 

The euryhaline G. ruber would be able to remain in the uppermost surface waters whereas G. 

sacculifer, which prefers more normal marine salinities, would likely sink below the low salinity 

layer or be excluded from the area if the low salinity layer was a short term or seasonal feature.

In a study of the last 5 ka in the nearby Orca Basin, Brown and others (1999), suggest 

that prominent negative excursions in 813C from surface dwelling planktic foraminifers in 

conjunction with changes in planktic foraminifer assemblages may be better markers for 

floodwater events in the GOM than 818O. One of the reasons that 813C may be a better proxy for 

floodwater events is that the 818O record is complicated by temperature changes. The lower 

temperatures of the floodwaters might cancel out small changes in surface salinity due to influx 

of the floodwaters. The suggestion requires further study. We have noted two levels at 1.2 kya 

and 4.0 kya in Figure 3 that show strong negative excursions in 813C that are associated with 

small negative excursions in 818O. These levels may also represent floodwater events.

Although drilling disturbance complicates details of the environmental record in 619A, 

the core disturbance cannot be used to explain the features we have noted. Mixing due to drilling
disturbance would tend to average out extremes in values and thus diminish the magnitude of the 

isotopic excursions indicating floodwater events. Thus, the overall observations and 

interpretations we have made on the 619A record are considered conservative and they 

demonstrate that a record of continental floodwater events is present in sediments of the Pigmy 

Basin.

Summary and Conclusions

AMS 14C dates demonstrate that the Pigmy Basin has a thick Holocene sequence with an 

accumulation rate of ~ 50cm/kyr. Isotopic and faunal data from Hole 619A shows clear 

evidence for changes in average sea surface temperature during the Holocene and at least two 

significant floodwater events at about 7 kya and 7.8 kya. Our reconnaissance study shows that 

the sediments of the Pigmy Basin hold the potential for developing decadal to century scale 

records that will contain information on major floods in the Mississippi Basin as well as 

environmental conditions in the GOM.

Acknowledgements

Samples provided by the Ocean Drilling Program. We thank Jack McGeehin and 

Dorinda R. Ostermann for assistance in AMS 14C and isotopic analyses. Jeff Schroeder and 

Elizabeth Castenson assisted in sample preparation and faunal census. We thank Harry Dowsett 

and Milan Pavich for comments on an initial draft of this report. We also thank Christopher 

Tracey for assistance in assembling the final draft.

Taxonomic Notes

List of taxa included in Table 3 follow below. Illustrations of most taxa can be found in 

Parker (1962) or Poore (1979).

Candeina nitida d'Orbigny 

Globigerina bulloides d'Orbigny
G. calida Parker

G. digitata Brady

G. falconensis Blow

G. rubescens Hofker

Globigerinella aequilateralis (Brady)

Globigerinita glutinata (Egger)

G. iota Parker

Globigerinoides conglobatus (Brady)

G. sacculifer (Brady)

G. ruber (d'Orbigny)

We recognize two informal categories of G. ruber. red and white varieties. Red variety is 

characterized by the presence, regardless of how slight, of red, or pink, pigmentation. 

White variety is characterized by the complete absence of such pigmentation.

G tenellus Parker

Globorotalia crassaformis (Galloway and Wissler)

G hirsuta (d'Orbigny)

G menardii (Parker, Jones, and Brady)

G scitula (Brady)

G tosaensis Takayanagi and Saito

G. truncatulinoides (d'Orbigny)

G tumida (Brady)

G ungulata Bermudez

Hastigerina pelagica (d'Orbigny)

Neogloboquadrina dutertrei (d'Orbigny)

N. p achy derma (Ehrenberg)

We separated N. pachyderma into right-coiling and left-coiling varieties. In addition, 

right-coiling specimens with >4 chambers in the last whorl are classified under the 

informal category of N. "dupac" and are considered to be gradational forms between N. 

pachyderma and N. dutertrei.

Orbulina universa d'Orbigny

10
Pulleniatina Banner and Blow

We separated Pulleniatina into two different species, depending on the position of the 

primary aperture. Pulleniatina finalis is characterized by the aperture positioned directly 

over a previous chamber. The aperture positioned over multiple previous chambers 

characterizes Pulleniatina obliquiloculata.

Sphaeroidinella dehiscens (Parker and Jones)

Other = species that were unidentified or not listed above.

References

Coplen, T.B., Kendall, C, and Hopple, J., 1983, Comparison of stable isotope reference samples. 

Nature, v. 302, p. 236-238.

Brown, P., Kennett, J. P., and Ingram, B. L., 1999, Marine evidence for episodic Holocene 

megafloods in North America and the northern Gulf of Mexico: Paleoceanography v. 14, p. 498- 

510.

Flower, B. P., and Kennett, J. P., 1990, The Younger Dryas cool episode in the Gulf of Mexico: 

Paleoceanography, v. 5, p. 949-961.

Dwyer, T., Mullins, H., Good, S., 1996, Paleoclimatic implications of Holocene lake-level 

fluctuations, Owasco Lake, New York: Geology, v. 24, p. 519-522.

Kennett, J. P., and Shackleton, N. J., 1975, Laurentide Ice Sheet Meltwater recorded in Gulf of 

Mexico Deep-Sea cores: Science, v. 188, p. 147-150.

Kennett, J. P., Elmstrom, K., and Penrose, N., 1985, The last deglaciation in Orca Basin, Gulf of 

Mexico: High-resolution planktonic foraminiferal changes, Palaeogeography, 

Palaeoclimatology, Palaeoecology, v. 50, p. 189-216.

11
Kipp, N., 1976, New transfer function for estimating past sea-surface conditions from sea-bed 

distribution of planktonic foraminiferal assemblages in the North Atlantic, Geological Society of 

America Memoir 145, p. 3-41.

Leventer, A., Williams, D. F., and Kennett, J. P., 1982, Dynamics of the Laurentide ice sheet 

during the last deglaciation: evidence from the Gulf of Mexico, Earth and Planetary Science 

Letters, v. 59, p. 11-17.

Parker, F., 1962, Planktonic foraminiferal species in Pacific sediments: Micropaleontology, v. 8, 

p. 219-254.

Poore, R. 1979, Oligocene through Quaternary planktonic foraminiferal biostratigraphy of the 

North Atlantic: DSDP Leg 49: In Luyendyk, B. P., Cann, J. R., and others, 1979, Initial Reports 

of the Deep Sea Drilling Project, v. 49: Washington (U.S. Government Printing Office), p. 447- 

517.

Roberts, M., Bench, G., Brown, T., Caffee, M., Finkel, R., Freeman, S., Hainsworth, L., 

Kashgarian, M., McAninch, J., Proctor, I., Southon, J., and Vogel, J., 1997, The LLNL AMS 

Facility, In: lull, J., Beck, J., and Burr, G., Eds., Proceedings of the Seventh International 

Conference on Accelerator Mass Spectrometry, Tucson, AZ, USA, North-Holland Press, p. 57- 

61.

12
105' 100

15°N

Figure 1 . Map showing location of Pigmy and Orca Basins. ODP Site 619A is in the Pigmy Basin
samples 

cmbsf 

O cm

25 

35 

49-,

55 

65 

78 

85 

95 

110 

122 

130 

155 

165 

177 

186 

198 ~N 

205 

218 --X 

225 

238--

245 

255 

265 

279 

300 

314 -x 

320 

330 

340 

350 

360 

373 -- 

380 

390 

400 

410 

420 

426 ~'

45(1

460 

470 

490 

500 

510 

519 

529 

s' 

!iCO 

CM

c 

_o

CO

^^^^H

CO

1(8

CO

C-C

:-

1 ;

samples 

cm from 

 sect, top

 25

[ 35

[~ 49

^--55

[ 65

[-- 78 

 85

^--95

I- 110

 122 

-- 130

 5 

h-15

p-27 

[-36 

x--48 

 55 

^- 68 

 75

 88

 95 

 105 

 115

 129

 0 

'-14 

 20 

 30 

 40 

 50 

 60 

<-- 73 

 80 

 90 

 100 

 110 

 120 

^- 126

IW

 10 

 20

 40

 50 

 60

 5 

 15

/

Q

Q

Q

e

e

Q

Q

0

0

^

»

Q

Q

*

^ 

O

e

o

e

e

e 

o

e

e

^

e

e

e

e

e

e

e

e

0

0

e

e

e

e

e

e

e

e

Q

e

e

^^

^^

^^ 

^^

e

e

e

®

Q 

e

0

o

o

o

e

e

e

e

e

o

Q

e

o

Q

O

o

o

e

e

e

e

o

0

o

0

e

e

o

o

e

e

e

0

o

o

e

e

e

e

e

^^

^^

e

e 

e

e

e

e

o

Q

e

o

o

o

o

o

o

e

/ /f

//

Q

Q

Q

Q

e

o

o

o

Q

Q

e

0

e

e

e

e

e

e

e

e

e

e

e

e

Q

e

e

e

o

e

e

Q

Q

Q

e

^^

^^

Q

e

e

e

e

e

< 14C 

< 14C

Composition:

Mud with silt laminae and rare 

foram sands.

Drilling Disturbance:

1 = Slightly disturbed

2 = Moderate

3 = High

4 = Soupy

Void 

IW = Interstitial Water sample taken

Abundance:

 = Trace 

Q =Rare 

0 =Few 

O = Common 

£ = Abundant

 25 = sample location 

bsf = below sea floor 

« 14C = AMSdate

Figure 2. ODP Hole 619A Core 1
14C years

0 -i

1000 - 2000 - 3000 - 4000 - Hi

5000 - 6000 - 7000 - 8000 - 9000 - 10000 - T T \ I T I 1 I

drilling disturbance 0.5 1 1.5 0 -1 -2 

G. ruber 813C G. ruber 818O

r 

0 -1 -20 20 40 0 15 30 0 10 20 0 10 20 0 3 6

G. sacc 818O G. ruber (white) G. sacculifer Gl. crassaformis N. "dupac" N. pachyderma- R

Figure 3: Selected isotope and faunal data from ODP 619A. Extent of drilling disturbance shown by column on left; interval with darker shading is more disturbed. 

Unshaded areas represent voids. Continental flood events are shown by stippled pattern on G. ruber isotope curve. ? = possible flood events.
Sample

0619A

0619A

0619A

Material

1,2W

1,3W

1.4W

88-90

80-82

40-42

cm

cm

cm

Mixed

Mixed

Mixed

planktics,

planktics,

planktics,

mostly

mostly

mostly

G.

G.

G.

tumida

tumida

tumida

14C age 14C age (corrected)

4230

7230

9620

3830

6830

9220

OOP Core 0619A Latitude: 27°11.61'N Longitude: 91°24.54'W Water depth = 2259 m 

Table 1. AMS Dates from OOP Hole 619A
Sample

619A1H,

619A1H,

619A1H,

619A1H,

619A1H,

619A1H,

619A1H,

619A1H,

619A1H,

619A1H,

619A1H,

619A1H,

619A1H,

619A1H,

619A1H,

619A1H,

619A1H,

619A1H,

619A1H,

619A1H,

619A1H,

619A1H,

619A1H,

619A1H,

619A1H,

619A1H,

619A1H,

619A1H,

619A1H,

619A1H,

619A1H,

619A1H,

619A1H,

619A1H,

619A1H,

619A1H,

619A1H,

619A1H,

619A1H,

1 25-27

1 55-57

1 78-80

1 110-112

1 122-124

25-7

215-17

2 36-38

2 48-50

2 55-57

2 68-70

2 75-77

2 88-90

2 95-97

2105-107

2115-117

2129-130

30-2

314-16

3 20-22

3 30-32

3 40-42

3 50-52

3 60-62

3 73-75

3 80-82

3 90-92

3100-102

3110-112

3120-122

3126-127

40-2

410-12

4 20-22

4 40-42

4 50-52

4 60-62

CC5-7

CC15-17

Depth

(cm)

25

55

78

110

122

155

165

186

198

205

218

225

238

245

255

265

279

300

314

320

330

340

350

360

373

380

390

400

410

420

426

450

460

470

490

500

510

519

529

Globigerinoides ruber

Age (corh

402

885

1255

1770

1963

2494

2655

2993

3186

3299

3508

3621

3830

3978

4189

4400

4696

5140

5436

5562

5774

5985

6196

6407

6682

6830

7047

7265

7482

7699

7829

8351

8568

8785

9220

9437

9655

9850

10067

813C

0.72

1.15

0.54

0.92

1.00

1.22

1.23

1.29

1.49

1.18

1.13

0.61

1.65

1.03

1.34

1.45

1.10

1.02

1.63

1.26

1.50

1.44

1.28

1.13

0.69

1.03

0.79

0.86

1.07

1.14

1.18

0.81

0.60

0.73

0.64

1.10

0.97

813C SD

0.02

0.01

0.01

0.02

0.01

0.01

0.02

0.01

0.01

0.00

0.01

0.01

0.02

0.01

0.02

0.01

0.01

0.01

0.01

0.01

0.01

0.01

0.01

0.02

0.01

0.01

0.00

0.01

0.00

0.01

0.02

0.01

0.01

0.01

0.01

0.01

0.01

818Q

-0.86

-1.08

-1.49

-0.90

-1.66

-1.89

-1.84

-1.63

-1.23

-1.33

-1.25

-1.51

-1.14

-1.63

-1.41

-1.38

-1.87

-1.40

-1.93

-1.93

-1.42

-2.01

-1.30

-1.47

-2.51

-1.36

-1.49

-2.32

-1.31

-1.04

-0.99

-0.66

-1.05

-1.43

-1.02

-1.29

-1.31

(white) Globigerinoides sacculifer

8180 SD

0.03

0.02

0.01

0.02

0.01

0.01

0.03

0.02

0.01

0.01

0.02

0.02

0.02

0.02

0.01

0.02

0.02

0.04

0.02

0.03

0.02

0.03

0.01

0.03

0.01

0.02

0.01

0.01

0.03

0.01

0.01

0.03

0.01

0.02

0.02

0.02

0.01

813C

1.63

2.16

1.72

1.91

1.89

1.49

2.22

2.09

2.07

2.13

1.83

1.74

1.72

1.86

1.68

1.69

1.79

1.68

1.42

1.73

1.73

1.74

2.19

1.65

1.60

1.61

2.05

1.92

1.61

1.69

1.72

1.94

1.54

1.51

1.53

1.49

1.56

813C SD

0.01

0.00

0.01

0.01

0.01

0.01

0.01

0.01

0.01

0.01

0.01

0.01

0.01

0.01

0.01

0.01

0.01

0.01

0.01

0.01

0.01

0.02

0.01

0.01

0.01

0.02

0.01

0.00

0.02

0.02

0.01

0.01

0.01

0.01

0.00

0.01

0.00

818Q

-0.53

-0.87

-1.22

-1.27

-0.85

-0.89

-1.07

-1.13

-0.97

-0.83

-0.97

-0.96

-0.83

-1.02

-1.28

-0.83

-1.23

-0.61

-0.77

-1.51

-0.98

-1.02

-1.13

-0.77

-0.56

-0.29

-0.73

-0.68

-0.53

-0.17

-0.51

-0.53

-0.35

-0.36

-0.56

-0.85

-0.54

818 0 SD

0.02

0.02

0.02

0.02

0.03

0.02

0.02

0.02

0.01

0.01

0.01

0.02

0.02

0.01

0.01

0.03

0.03

0.02

0.02

0.01

0.02

0.03

0.02

0.02

0.01

0.02

0.02

0.02

0.02

0.02

0.01

0.01

0.02

0.01

0.01

0.02

0.01

Table 2. Isotope values from OOP Hole 619A
6

//////* st/SM . /, /£. /v 

A <y <$> o° 6,* \® 0or vo\^ ff1 0&0 .<9-\<p j§> & & v^y xc^ x*° vO° v^ \^ ^ riy $ ^ 

 / V -^ \^ \^ V V ^ ^ ^ / / cT / ^ *° <T ^ * \^ &^V ^ &^ <f 

Set Top Bot (cm) O^ (£ (£ (£ (£ < $ (£ (£

1, 2W 5 7

1, 2W 15 17

1, 2W 36 38

1, 2W 48 50

1, 2W 55 57

1, 2W 68 70

1, 2W 75 77

1, 2W 88 90

1, 2W 95 97

1, 2W 105 107

1 , 2W 115 117

1, 2W 129 130

1, 3W 0 2

1 , 3W 14 16

1, 3W 20 22

1, 3W 30 32

1, 3W 40 42

1, 3W 50 52

1, 3W 60 62

1, 3W 73 75

1, 3W 80 82

1, 3W 90 92

1, 3W 100 102

1, 3W 120 122

1, 3W 126 127

1, 4W 0 2

1 , 4W 10 12

1, 4W 20 22

1, 4W 40 42

1, 4W 50 52

1, 4W 60 62

1,CC 5 7

1,CC 15 17

7

3

19

5

11

3

1

8

15

9

4

6

4

3

0

3

6

11

12

6

6

6

17

8

5

6

2

8

6

7

11

2

2

18

17

12

24

16

24

12

57

38

31

36

44

15

11

22

6

13

35

38

21

52

38

11

12

17

26

39

59

33

41

44

49

48

101

70

62

52

81

80

76

146

43

63

91

90

79

123

103

121

75

71

76

109

44

80

157

76

81

60

69

90

63

65

48

34

70

1

3

0

2

3

1

2

2

1

0

0

2

1

5

2

2

1

0

0

0

0

0

0

0

0

1

0

0

0

0

0

0

0

37

25

30

27

22

19

12

29

32

21

14

36

35

34

54

56

63

70

54

27

52

34

36

11

28

22

9

55

30

7

19

22

11

0

0

0

0

0

1

2

0

1

0

0

0

0

0

0

0

0

0

0

1

0

0

1

0

0

0

0

1

2

1

0

1

1

2

3

3

17

7

1

2

11

11

0

4

11

0

7

5

8

10

5

10

13

4

18

8

12

4

2

6

13

13

10

1

6

11

11

8

9

19

5

6

8

15

9

7

8

7

6

4

1

1

0

1

2

0

0

2

9

10

13

12

18

17

12

9

7

11

10

AV AW *& voP \nP <0 ,nP <0 <0 <0 <0 <0 A® J& j& <0 j^ '^ .cy1 <0 

w vi/r/.,/ r/> xx^^^x^yyy^x

& & ^ ^ & ^f & & & & & 0 & & & & ^ v & 0 * 

9

8

12

25

8

6

10

25

26

10

20

9

15

25

25

15

11

12

30

8

4

15

6

19

15

22

16

20

5

15

9

21

24

3

3

7

3

1

0

0

3

4

0

0

1

0

1

4

0

0

1

1

0

2

2

1

4

2

0

1

3

0

1

2

2

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

3

0

4

0

0

12

8

1

17

0

0

29

22

22

14

13

20

19

33

22

23

39

23

14

24

33

26

41

43

32

30

50

43

68

33

30

32

33

33

31

47

55

19

26

9

16

12

9

7

18

4

0

2

0

3

0

0

1

0

0

0

0

0

0

0

0

41

10

21

34

41

42

27

24

27

19

24

0

1

0

3

0

0

0

15

0

0

0

0

0

0

1

0

0

0

1

1

0

0

2

7

5

8

13

26

14

17

41

11

16

2

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

5

0

0

3

1

0

1

0

0

0

2

2

0

3

1

0

0

2

0

1

0

0

0

0

0

0

0

0

0

0

0

0

1

0

6

3

1

1

3

2

0

0

2

2

19

24

28

24

30

29

10

16

2

16

5

8

5

2

1

10

4

12

4

5

4

2

0

1

1

2

2

3

2

2

0

1

3

8

4

6

3

9

1

3

2

4

8

3

4

2

3

0

2

2

3

2

1

2

1

10

1

4

8

3

7

5

13

0

1

0

17

17

17

13

22

21

19

28

13

6

12

6

10

9

11

21

8

23

12

13

9

6

10

7

4

12

7

7

6

15

11

4

5

17

27

34

26

20

32

74

57

43

31

11

15

15

12

26

25

19

18

27

16

15

21

40

33

33

41

27

27

20

28

21

20

25

2

0

0

1

2

0

2

3

2

3

1

1

1

2

1

1

0

1

2

1

2

1

0

1

0

1

0

0

0

1

0

0

0

2

0

3

10

6

1

4

7

11

3

3

5

6

1

9

4

1

2

9

2

10

11

1

1

5

2

4

2

0

0

5

1

3

6

0

3

4

0

0

9

11

6

1

1

1

4

0

4

7

5

2

3

2

1

4

3

8

4

3

7

0

2

3

0

0

0

4

1

5

6

10

2

10

17

9

2

11

3

8

5

7

9

12

8

3

9

15

15

11

6

10

10

7

9

7

1

3

3

5

29

34

16

14

21

20

19

23

16

7

13

6

17

10

7

11

9

20

11

8

4

16

28

17

6

9

12

7

7

19

18

0

1

0

0

0

0

1

0

0

0

0

0

0

0

0

0

6

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

1

0

0

0

0

0

0

0

0

0

0

1

0

0

0

0

0

0

1

0

0

0

0

0

0

0

0

0

0

0

1

0

0

0

1

2

0

0

0

0

0

0

0

0

1

0

1

0

2

1

1

1

2

0

0

0

0

0

3

0

Table 3a. OOP Hole 619A. Raw counts from faunal census splits. Sample designation 1, 2W 5-7cm stands for: core 1, 

half, 5-7cm below top of section.
. v; . ^ \ov W r<o \_<s \<o & G1 \v> <v xOx w <x »vy 

yjy &^ oW rp \s -^ _< > ^P 6C" o1^ ir K° n. $ i\ v $ ,x 0^ flj

C& ^ <^ cP <-,& ^> ^ AO 0<v ^cp .& .^fc- £,< > JJ- <JS .^ .£ AO .0 X^ .^S ^ & 

Set Top Bot (cm;

1 , 2W 5 7

1 , 2W 15 17

1,2W 36 38

1, 2W 48 50

1,2W 55 57

1,2W 68 70

1,2W 75 77

1, 2W 88 90

1,2W 95 97

1, 2W 105 107

1 , 2W 115 117

1, 2W 129 130

1, 3W 0 2

1 , 3W 14 16

1, 3W 20 22

1,3W 23 25

1, 3W 30 32

1, 3W 40 42

1, 3W 50 52

1, 3W 60 62

1, 3W 80 82

1,3W 90 92

1 , 3W 1 00 1 02

1, 3W 120 122

1, 3W 126 127

1 , 4W 0 2

1 , 4W 10 12

1, 4W 20 22

1, 4W 40 42

1,4W 50 52

1, 4W 60 62

1.CC 57

1,CC 15 17

(/

2

1

7

2

4

1

0

2

5

4

1

2

2

1

0

2

1

2

3

4

2

2

4

3

2

2

1

2

2

2

3

1

1

/\V* -AV -XV y>\v ->V XV

/ / / / / & ? AC? -}fiP -Jft jflP / Ux<

cr cr cr cr <^ cr

5

6

4

8

6

9

4

12

12

13

13

16

6

4

7

8

2

5

1 1

12

19

12

2

4

6

8

12

14

12

14

14

21

17

30

24

21

17

28

29

25

30

14

26

32

32

33

43

31

40

37

28

22

24

16

25

35

26

27

19

22

21

23

22

15

15

24

0

1

0

1

1

0

1

0

0

0

0

1

0

2

1

0

1

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

11

9

10

9

8

7

4

6

10

9

5

13

15

12

17

10

17

23

22

17

19

1 1

8

4

9

7

3

13

11

2

6

9

4

0

0

0

0

0

0

1

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

1

0

0

0

0

1

1

1

6

2

0

1

2

3

0

1

4

0

2

2

5

2

4

2

3

1

6

2

4

1

1

2

3

5

3

0

3

4

fSSSf/S/SS/SSSS/SS

</ </ </ / ^° </ ^° (/ </ </ </ </ </ </ </ </ </ </ 

3

3

3

6

2

2

3

3

3

3

3

3

3

1

0

0

0

0

0

1

0

1

2

3

4

4

6

4

4

3

2

5

3

3

3

4

8

3

2

3

5

8

4

7

3

6

9

8

3

5

4

4

10

1

5

1

7

5

7

5

5

2

5

3

9

8

1

1

2

1

0

0

0

1

1

0

0

0

0

0

1

0

0

0

0

0

1

1

0

1

1

0

0

1

0

0

1

1

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

1

0

1

0

0

3

3

0

5

0

0

9

8

8

5

5

7

6

7

7

9

14

8

6

8

10

11

8

15

13

10

18

14

15

11

10

10

10

8

1 1

16

17

8

9

3

6

4

3

2

6

1

0

1

0

1

0

0

0

0

0

0

0

0

0

0

0

9

3

7

1 1

13

10

10

8

8

8

8

0

0

0

1

0

0

0

3

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

2

2

3

4

6

5

6

13

5

6

1

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

1

0

0

1

0

0

0

0

0

0

1

1

0

1

0

0

0

1

0

0

0

0

0

0

0

0

0

0.

0

0

0

0

0

0

2

1

0

0

1

1

0

0

1

1

6

8

10

8

10

10

3

3

1

7

2

3

2

1

0

2

3

1

4

1

1

1

0

0

0

1

1

1

1

1

0

0

1

2

1

2

1

3

0

1

0

1

3

1

1

1

1

0

0

1

1

1

1

1

0

2

0

1

3

1

2

2

4

0

0

0

5

6

6

4

8

8

6

6

4

2

4

2

4

3

3

5

6

3

7

4

3

2

2

2

1

4

2

2

2

5

3

2

2

5

9

12

8

7

12

25

12

14

13

4

5

6

4

8

6

8

7

6

9

5

7

9

1 1

1 1

13

8

6

7

9

7

9

9

1

0

0

0

1

0

1

1

1

1

0

0

0

1

0

0

0

0

0

1

1

0

0

0

0

0

0

0

0

0

0

0

0

1

0

1

3

2

0

1

1

3

1

1

2

3

0

3

1

1

0

1

3

4

3

0

0

2

1

1

0

0

0

2

0

1

2

0

1

1

0

0

3

2

2

0

0

0

2

0

1

1

2

2

1

1

0

1

1

3

1

1

2

0

1

1

0

0

0

1

0

2

2

3

1

3

3

3

1

4

1

3

2

2

3

3

4

2

1

5

5

2

2

3

3

2

2

3

0

1

1

2

9

12

5

5

7

7

6

5

5

3

5

2

7

3

2

3

3

3

6

4

1

5

6

6

2

3

4

2

3

6

6

0

0

Table 3b. 619A Faunal percentage data from faunal census. Planktic foraminifer percentage calculated as percenta

Benthic percentages calculated from percentage of total foraminifers.