Preliminary studies of planktonic foraminifera in surface
them from the earlier supercycles that terminate at times of highest sea level. This change in character may represent glacio-eustatic effects superimposed upon a longer term eustatic driving mechanism. Also, this longer term eustatic driving mechanism has probably remained constant during the Mesozoic and Cenozoic, because the character of the individual sea-level cycles has not changed during this period (Vail et al. 1977). If continental ice sheets are a late Cenozoic feature only, then an alternate mechanism must be found to produce the rapid falls of sea level reported by Vail and others (1977). This research was supported by National Science Foundation grant DPP 78-08512. References Hayes, D. E., Frakes, L. A. et al. 1975. Initial reports of the Deep Sea Drilling Project, Vol. 28. Washington, D.C.: U.S. Government Printing Office. Keigwin, L. D., Jr. In press. Paleoceanographic change in the Pacific at the Eocene-Oligocene boundary: DSDP sites 277 and 292. Nature. Kemp, E. M., and Barrett, P. 1975. Antarctic glaciation and early Tertiary vegetation. Nature, 258(5535), 507-508.
Preliminary studies of planktonic foraminifera in surface sediments from the south Atlantic Ocean HAYDEE LENA
Department of Biological Sciences Florida Institute of Technology Melbourne, Florida 32901
The research reported in this paper is part of a continuing study of foraminifera in surface sediments from the southern ocean. It covers the planktonic foraminifera of 23 coretop samples from 21 deep-sea piston and trigger cores collected in the southwest Atlantic Ocean during cruise 0775 of the ARA Islas Orcadas (see figure). The cores were collected in an area bounded by 48° to 23°W longitude and 48° to 58°S latitude at ocean depths ranging from 1,500 to 5,000 meters. The planktonic foraminiferal fauna was rich and composed chiefly of large specimens. Only four top-samples from piston cores 15, 27, and 34 and trigger core 34 lacked planktonic foraminifera. This can be explained by the effects of dissolution, since these samples were collected at ocean depths ranging between 4,000 and 5,000 meters and the calcium-carbonate-compensation depth previously calculated for this area is between 2,100 and 3,000 meters (Malmgren and Cronbiad 1978). 1980 REVIEW
Kennett, J. P. 1977. Cenozoic evolution of antarctic glaciation, the circum-antarctic ocean, and their impact on global paleoceanography. Journal of Geophysical Research, 82(3), 3843-3860. Mayewski, P. A. 1975. Glacial geology and late Cenozoic history of the Transantarctic Mountains, Antarctica (Report 56). Columbus: Ohio State University, Institute of Polar Studies. Pitman, W.C., III. 1979. The effect of eustatic sea level changes on stratigraphic sequences at Atlantic margins. AAPG Memoir 29. Tulsa: American Association of Petroleum Geologists. Savin, S. M., Douglas, R. G., and Stehli, F. G. 1975. Tertiary marine paleotemperatures. Geological Society of America Bulletin, 86(2), 1499-1510. Shackleton, N. J . , and Kennett, J . P. 1975. Paleotemperature history of the Cenozoic and the initiation of antarctic glaciation: Oxygen and carbon isotope analysis in DSDP sites 277,279 and 281. In J.P. Kennett and R.E. Houtz (Eds.), Initial reports of the Deep Sea Drilling Project, Vol. 29. Washington, D.C.: U.S. Government Printing Office. Vali, P. R. 1980. Personal communication. Vail, P. R., Mitchum, R. M., Jr., and Thompson, S., III. 1977. Global cycles of relative changes of sea level. In C. E. Payton (Ed.), Seismic stratigraphy—Applications to hydrocarbon exploration, AAPG Memoir 26. Tulsa: American Association of Petroleum Geologists.
Eleven planktonic foraminiferal taxa were distinguished. One of these is cosmopolitan (Globigerinita glutinata), two are typical of cold water (Globigerinit a uvula and Globoquadrina pachyderma), and the others are typical of coldtemperate water (Globigerina bulloides, sensu latu; G. quinqueloba lingulata; G. quinqueloba quinqueloba; Globorotalia inflata; G. scitula, forma typica; C. scitula, forma gigantea; G. truncatulinoides malvinensis; and G. truncatulinoides truncatulinoides) (Be 1969; Boltovskoy 1%9; Boltovskoy and Watanabe 1980; Lena and Watanabe in press). The sinistral tests of Globoquadrina pachyderma (98.6 percent), Globorotalia truncatulinoides (98.6 percent), and Globigerina bulloides (70 percent) were dominant. These values agree with the results of others who have studied cold and cold-to-temperate water areas (Bandy 1960; Be 1%9; Bol tovskoy and Watanabe 1979; Malmgren and Cronbiad 1978; Malmgren and Kennett 1976). In general, the planktonic foraminiferal fauna of the surface sediments analyzed was typical of subantarctic water, and the frequencies of the species determined in the sediments agree with those of the surface water layer (Be and Tolderlund 1971). The only exceptions were (1) Globoquad rina pachyderma, with a high frequency of sinistral tests of 98.6 percent, a value typical of antarctic waters (Boltovskoy and Watanabe 1979); and (2) Globorotalia inflata, with a frequency of 26.7 percent, which is almost three times greater than that previously determined for surface waters (Be and Tolderlund 1971). The first discrepancy can be explained by the fact that the samples were collected near the subantarctic limit of the Antarctic Polar Front Zone, where the antarctic water sinks below the 101
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subantarctic water. The second discrepancy can be explained by an advance of a water-warming trend toward the south in the recent geologic past (Be 1969). The abundance of Globorotalia truncatulinoides and the absence of pre-Pleistocene species indicate that the sediments analyzed are Quaternary. I thank D. Cassidy (Florida State University) for supplying me with material from the collections of the
Islas Orcadas. References Bandy, 0. L. 1960. The geologic significance of coiling ratios in the foraminifer Globigerina pachyderma (Ehrenberg). Journal of Paleontology, 34(4), 671-681. Be, A. W. H. 1969. Planktonic foraminifera. In V. C. Bushnell and J. W. Hedgpeth (Eds.), Distribution of selected groups of marine
invertebrate in waters south of 350S latitude, Antarctic map folio series (Folio II, Sheets 9-12). New York: American Geographic
Society. Be, A. W. H., and Tolderlund, D. S. 1971. Distribution and ecology of living planktonic foraminifera in surface waters of the Atlantic and Indian Oceans. In B. M. Funnell and W. R. Riedel (Eds.), The micropaleontology of oceans. Oxford: Cambrdige University Press.
102
Boltovskoy, E. 1969. Living planktonic foraminifera at the 90°E meridian from the Equator to the Antarctic. Micropaleontology, 15(2), 237-255. Boltovkoy, E., and Watanabe, S. 1979. Foraminiferos planctônicos colectados por la campaha antkrtica argentina "Islas Orcadas 05/75." Museo Argentino de Ciencias Naturales "Bernardino Rivadavia," Revista de Hidrobiologia, 5(10), 229-240. Boltovskoy, E., and Watanabe, S. 1980. Foraminiferos de los sedimentos cuaternarios entre Tierra del Fuego e Islas Georgias del Sur. Museo Argentino de Ciencias Naturales "B. Rivadavia," Revista de Geologza, 8(4), 95-124. Cassidy, D. S., Ciesielski, P. F., Kaharoeddin, F. A., Wise, S. W., Jr., and Zemmels, I. 1977. ii Islas Orcadas cruise 0775 sediments descriptions (Contribution 45). Tallahassee: Florida State University, Department of Geology, Sedimentology Research Laboratory. Lena, H., and Watanabe, S. In press. Planktonic foraminifera collected by the R/V Hero, cruise 71-4. Antarctic Journal of the U.S., 15(5). Malmgren, B. A., and Cronblad, H. C. 1978. Planktonic foraminiferal dissolution at high latitudes of the southwestern Atlantic. Antarctic Journal of the U.S., 13(4) 107-109. Malmgren, B. A., and Kennett, J. P.1976. Size variations in Globigerina bulloides d'Orbigny as a Quaternary paleoclimatic index in the Southern Ocean. Antarctic Journal of the U.S., 11(3), 177-178.
ANTARCrIC JOURNAL
Preliminary studies of planktonic foraminifera in surface sediments from the south Atlantic Ocean HAYDEE LENA
Department of Biological Sciences Florida Institute of Technology Melbourne, Florida 32901
The research reported in this paper is part of a continuing study of foraminifera in surface sediments from the southern ocean. It covers the planktonic foraminifera of 23 coretop samples from 21 deep-sea piston and trigger cores collected in the southwest Atlantic Ocean during cruise 0775 of the ARA Islas Orcadas (see figure). The cores were collected in an area bounded by 48° to 23°W longitude and 48° to 58°S latitude at ocean depths ranging from 1,500 to 5,000 meters. The planktonic foraminiferal fauna was rich and composed chiefly of large specimens. Only four top-samples from piston cores 15, 27, and 34 and trigger core 34 lacked planktonic foraminifera. This can be explained by the effects of dissolution, since these samples were collected at ocean depths ranging between 4,000 and 5,000 meters and the calcium-carbonate-compensation depth previously calculated for this area is between 2,100 and 3,000 meters (Malmgren and Cronbiad 1978). 1980 REVIEW
Kennett, J. P. 1977. Cenozoic evolution of antarctic glaciation, the circum-antarctic ocean, and their impact on global paleoceanography. Journal of Geophysical Research, 82(3), 3843-3860. Mayewski, P. A. 1975. Glacial geology and late Cenozoic history of the Transantarctic Mountains, Antarctica (Report 56). Columbus: Ohio State University, Institute of Polar Studies. Pitman, W.C., III. 1979. The effect of eustatic sea level changes on stratigraphic sequences at Atlantic margins. AAPG Memoir 29. Tulsa: American Association of Petroleum Geologists. Savin, S. M., Douglas, R. G., and Stehli, F. G. 1975. Tertiary marine paleotemperatures. Geological Society of America Bulletin, 86(2), 1499-1510. Shackleton, N. J . , and Kennett, J . P. 1975. Paleotemperature history of the Cenozoic and the initiation of antarctic glaciation: Oxygen and carbon isotope analysis in DSDP sites 277,279 and 281. In J.P. Kennett and R.E. Houtz (Eds.), Initial reports of the Deep Sea Drilling Project, Vol. 29. Washington, D.C.: U.S. Government Printing Office. Vali, P. R. 1980. Personal communication. Vail, P. R., Mitchum, R. M., Jr., and Thompson, S., III. 1977. Global cycles of relative changes of sea level. In C. E. Payton (Ed.), Seismic stratigraphy—Applications to hydrocarbon exploration, AAPG Memoir 26. Tulsa: American Association of Petroleum Geologists.
Eleven planktonic foraminiferal taxa were distinguished. One of these is cosmopolitan (Globigerinita glutinata), two are typical of cold water (Globigerinit a uvula and Globoquadrina pachyderma), and the others are typical of coldtemperate water (Globigerina bulloides, sensu latu; G. quinqueloba lingulata; G. quinqueloba quinqueloba; Globorotalia inflata; G. scitula, forma typica; C. scitula, forma gigantea; G. truncatulinoides malvinensis; and G. truncatulinoides truncatulinoides) (Be 1969; Boltovskoy 1%9; Boltovskoy and Watanabe 1980; Lena and Watanabe in press). The sinistral tests of Globoquadrina pachyderma (98.6 percent), Globorotalia truncatulinoides (98.6 percent), and Globigerina bulloides (70 percent) were dominant. These values agree with the results of others who have studied cold and cold-to-temperate water areas (Bandy 1960; Be 1%9; Bol tovskoy and Watanabe 1979; Malmgren and Cronbiad 1978; Malmgren and Kennett 1976). In general, the planktonic foraminiferal fauna of the surface sediments analyzed was typical of subantarctic water, and the frequencies of the species determined in the sediments agree with those of the surface water layer (Be and Tolderlund 1971). The only exceptions were (1) Globoquad rina pachyderma, with a high frequency of sinistral tests of 98.6 percent, a value typical of antarctic waters (Boltovskoy and Watanabe 1979); and (2) Globorotalia inflata, with a frequency of 26.7 percent, which is almost three times greater than that previously determined for surface waters (Be and Tolderlund 1971). The first discrepancy can be explained by the fact that the samples were collected near the subantarctic limit of the Antarctic Polar Front Zone, where the antarctic water sinks below the 101
48W
70W 65W 60W 55*w 50w 4W 40W 351w
s.s
46W
44W
42W
ao00
4
,---
• 42
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•40
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--00^
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S
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555
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ME
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TNYM(TRV
300 60_5
I I I
I
I
I
I
1 ( I I 1 1 bO.S
70* 65W bO# Ww SOW 45* 40w 35.w 30w 251w 20w 15,w
ARA Islas Orcadas
0775 sample locations (after Cassidy, Ciesisiski, Kaharoeddin, Wise, and Zemmol* 1977).
subantarctic water. The second discrepancy can be explained by an advance of a water-warming trend toward the south in the recent geologic past (Be 1969). The abundance of Globorotalia truncatulinoides and the absence of pre-Pleistocene species indicate that the sediments analyzed are Quaternary. I thank D. Cassidy (Florida State University) for supplying me with material from the collections of the
Islas Orcadas. References Bandy, 0. L. 1960. The geologic significance of coiling ratios in the foraminifer Globigerina pachyderma (Ehrenberg). Journal of Paleontology, 34(4), 671-681. Be, A. W. H. 1969. Planktonic foraminifera. In V. C. Bushnell and J. W. Hedgpeth (Eds.), Distribution of selected groups of marine
invertebrate in waters south of 350S latitude, Antarctic map folio series (Folio II, Sheets 9-12). New York: American Geographic
Society. Be, A. W. H., and Tolderlund, D. S. 1971. Distribution and ecology of living planktonic foraminifera in surface waters of the Atlantic and Indian Oceans. In B. M. Funnell and W. R. Riedel (Eds.), The micropaleontology of oceans. Oxford: Cambrdige University Press.
102
Boltovskoy, E. 1969. Living planktonic foraminifera at the 90°E meridian from the Equator to the Antarctic. Micropaleontology, 15(2), 237-255. Boltovkoy, E., and Watanabe, S. 1979. Foraminiferos planctônicos colectados por la campaha antkrtica argentina "Islas Orcadas 05/75." Museo Argentino de Ciencias Naturales "Bernardino Rivadavia," Revista de Hidrobiologia, 5(10), 229-240. Boltovskoy, E., and Watanabe, S. 1980. Foraminiferos de los sedimentos cuaternarios entre Tierra del Fuego e Islas Georgias del Sur. Museo Argentino de Ciencias Naturales "B. Rivadavia," Revista de Geologza, 8(4), 95-124. Cassidy, D. S., Ciesielski, P. F., Kaharoeddin, F. A., Wise, S. W., Jr., and Zemmels, I. 1977. ii Islas Orcadas cruise 0775 sediments descriptions (Contribution 45). Tallahassee: Florida State University, Department of Geology, Sedimentology Research Laboratory. Lena, H., and Watanabe, S. In press. Planktonic foraminifera collected by the R/V Hero, cruise 71-4. Antarctic Journal of the U.S., 15(5). Malmgren, B. A., and Cronblad, H. C. 1978. Planktonic foraminiferal dissolution at high latitudes of the southwestern Atlantic. Antarctic Journal of the U.S., 13(4) 107-109. Malmgren, B. A., and Kennett, J. P.1976. Size variations in Globigerina bulloides d'Orbigny as a Quaternary paleoclimatic index in the Southern Ocean. Antarctic Journal of the U.S., 11(3), 177-178.
ANTARCrIC JOURNAL
