Basal sediment ages of Islas Orcadas cruise 7 piston cores
flanks. Miocene coccolith ooze deposition ceased when the center of high carbonate productivity (and the Miocene Polar Front?) migrated north of the bank in response to deteriorating climate associated with a severe late Miocene continental glaciation on the antarctic continent. Strong bottom currents associated with the Cretaceous Tertiary event, the early Miocene opening of the Drake Passage, and the late Miocene antarctic glaciation caused scouring and removal of significant volumes of sediment, thus contributing to the complex erosional history of the bank. During the late Miocene the last and most severe of these events truncated the previously deposited upper Cretaceous to Miocene sequence of sediments of the bank. The primary erosional agent during the late Miocene was probably a northerly component of the circumantarctic deep water that impinged on the bank from the southwest. Erosion of older pelagic oozes ceased with the deposition of Plio- Pleistocene glacial marine clastics that essentially "armored" the sediment surface with a protective, erosionresistant cover. Carbonate deposition in the study area resumed during the latest Pleistocene, when the polar front migrated to a mean position near the southern margin of the bank. This research was supported by National Science Foundation grant DPP 74-20109. Operational support by the Argentine Naval Hydrographic Service is gratefully acknowledged.
Project. In: P.F. Barker, I.W.D. Dalziel, et al., Initial Reports of the Deep Sea Drilling Project, 36. U.S. Government Printing Office, Washington, D.C. 575-688. Gordon, A.L., D.T. Georgi, and H.W. Taylor. In press. Antarctic polar front zone in the western Scotia Sea - summer I 975.Journal of Physical Oceanography. Leonardi, A., and M. Ewing. 1971. Bathyrnetry chart of the Argentine Basin (map, no scale). In: Physics and Chemistry of the Earth, London, Pergamon Press. 8. McCollum, D.W. 1975. Antarctic Cenozoic diatoms: leg 28, Deep Sea Drilling Project. In L.A. Frakes, D.E. Hayes, et al., Initial Reports of the Deep Sea Drilling Project, 28. U.S. Government Printing Office, Washington, D.C. 515-572. Sclater, T.G., D. Woodroffe, H. Dick, D. Georgi, S.W. Wise, and P. Ciesielski. 1977. Scientific report for Islas Orcadas cruise 11. AntarcticJournalof the U.S., XII(4): 62-65. Warnke, D.A., P. Bruchhausen, J . LaBrecque, P.F. Ciesielski and A. Federman. 1976. ARA Islas Orcadas cruise 7. Antarctic Jour. nalof the U.S., XI(2): 70-73. Weaver, F.M. 1976. Late Miocene and Pliocene radiolarian paleobiogeography and biostratigraphy of the southern ocean. Tallahassee, Department of Geology, Florida State University, Ph.D. Dissertation (unpublished). 175 p. Wise, SW., and F.H. Wind. 1977. Mesozoic and Cenozoic calcareous nannofossils recovered by DSDP leg 36 drilling on the Falkland Plateau, Atlantic sector of the southern ocean. In: P.F. Barker, I.W.D. Dalziel, et al., Initial Reports of the Deep Sea Drilling Project, 36. U.S. Government Printing Office, Washington, D.C. 269-492.
References
Barker, P.F. 1977. Correlations between sites on the Eastern Falkland Plateau by means of seismic reflection profiles, Leg 36, Deep Sea Drilling Project. In: P.F. Barker, I.W.D. Dalziel, et al., Initial Reports of the Deep Sea Drilling Project, 36. U.S. Government Printing Office, Washington, D.C. 971-900. Barker, P.F., I.W.D. Dalziel, D.H. Elliot, C.C. von der Borch, R.W. Thompson, G. Plafker, R.C. Tjalsma, S.W. Wise, M.G. Dinkelman, A.M. Gombos, A. Lonardi, andJ. Tarney. 1977. Initial Reports of the Deep Sea Drilling Project, 36. U.S. Government Printing Office, Washington, D.C. 1080 p. Busen, Karen L., and S.W. Wise. 1977. Silicoflagellate biostratigraphy, Deep Sea Drilling Project leg 36. In: P.F. Barker, I.W.D. Dalziel, et al., Initial Reports of the Deep Sea Drilling Project, 36. U.S. Government Printing Office, Washington, D.C. 697-744. Ciesielski, P.F., 1975. Biostratigraphy and paleoecology of Neogene and Oligocene silicoflagellates from cores recovered during antarctic leg 28, Deep Sea Drilling Project. In: D.E. Hayes, L.A. Frakes, et al., Initial Reports of the Deep Sea Drilling Project, 28. U.S. Government Printing Office, Washington, D.C. 625-691. Ciesielski, P.F. and S.W. Wise. In press. Geologic history of the Maunice Ewing Bank of the Falkland Plateau (Southwest Atlantic section of the southern ocean) based on piston and drill cores. Marine Geology (special issue; D.E. Hayes, editor). aesielski, P.F., W.V. Sliter, F.H. Wind, and S.W. Wise. In press. Paleoenvironmental analysis and correlation of a Cretaceous Islas Orcadas core from the Falkland Plateau, Southwest Atlantic. Marine Micropaleontology, 2. Ciesielski, P.E., W.V. Sliter, F.H. Wind, and S.W. Wise. 1977. A Cretaceous Islas Orcadas core from the Falkland (Malvinas) Plateau, southwest Atlantic. Antarctic Journal of the U. S., XII(4): 65-67. Combos, A . M. 1977. Paleogene and Neogene diatoms from the Falkland Plateau and Malvinas Outer Basin, Deep Sea Drilling 70
Basal sediment ages of Islas Orcadas cruise 7 piston cores PAUL F. CIESIELSKI and SHERWOOD W. WISE, JR.
Antarctic Marine Geology Research Facility Department of Geology Florida State University Tallahassee, Florida 32306
As an aid to other investigators wishing to study ARA Islas Orcadas cores, we present here preliminary basal sediment ages for 45 piston cores taken on cruise 7, the first multidisciplinary cruise (marine geology, physical oceanography, and geophysics) of the ship to the southwest Atlantic sector of the southern ocean. This cruise, which began and ended at Buenos Aires, concentrated on the Falkland (Malvinas) Plateau, the South Georgia Basin, and peripheral areas (Warnke et al. 1976). The table lists piston core numbers, latitude, longitude, water depth, sample interval, age, and sediment lithology of the basal sedimentary unit. Sampling. Fully recovered cores, stored in plastic liners, were sampled within 1 to 6 centimeters of their base; those with disturbed basal sedimentary sequences were sampled above the disturbed sequence as well. For all such cores sampled in this manner, both samples gave similar ages. Seven cores comprise a second group, from which samples ANTARCTIC JOURNAL
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ISLAS ORCADAS 0775 SAMPLE LOCATIONS • PISTON CORE 8 TRIGGER CORE
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Islas Orcadas cruise 7 sample locations.
025
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were taken from material retrieved by the core cutter and/or catcher (c/c). This sediment is stored as bag samples. Laboratory. Smear-slide preparations from each sample were examined for their calcareous nannofossil, diatom, and silicoflagellate contents and were age-dated utilizing the high- latitude biostratigraphic zonations recently summarized by: Calcareous nannofossils: Wise and Wind (1977). Diatoms: McCollum (1975); Gombos (1977); Weaver (1976). Silicoflagellates: Ciesielski (1975); Busen and Wise (1977). Pliocene and Quaternary sedimentary sequences were dated using the diatom biostratigraphic zonation of McCollum (1975), which has been used successfully in the southwest Atlantic by Gombos (1977). Weaver's (1976) modification of the early Pliocene portion of McCollum's diatom zonation was used where possible. The sediment age-dates in the table are preliminary. A number of the determinations are based on examination of only one sample and not on an examination of the entire core. For those cases, it is difficult to detect complicating factors such as reworking or contamination that might lead to an improper age assignment. Investigators planning detailed work on these cores may wish to obtain additional confirmation of the age-dates provided. More detailed age assignments (down to subepoch or biostratigraphic zone) for some of the cruise 7 cores are given in Ciesielski et al. (in press) and Ciesielski and Wise (in press). This research was supported by National Science Foundation grant OPP 74-20109. Operational support by the Argentine Naval Hydrographic Service is gratefully acknowledged. October 1977
30W 25W 2" I3•W
References
Busen, Karen L., and S.W. Wise, Jr. 1977. Silicoflagellate biostratigraphy. Deep Sea Drilling Project Leg 36. In: P.F. Barker, I.W.D. Dalziel, et al., Initial Reports of the Deep Sea Drilling Project, 36. U.S. Government Printing Office, Washington, D.C. 697-744. Cassidy, Dennis S., P.F. Ciesielski, F.A. Kaharoeddin, S.W. Wise and I. Zemmels. 1977. ARA Islas Orcadas cruise 0775 sediment descriptions. Sedimentology Research Laboratory, Department of Geology, Florida State University. Contribution, 45. 76 p. Ciesielski, Paul F. 1975. Biostratigraphy and paleoecology of Neogene and Oligocene silicoflagellates from cores recovered during antarctic leg 28, Deep Sea Drilling Project. In: L.A. Frakes, D.E. Hayes, et al., Initial Reports of the Deep Sea Drilling Project, 28. U.S. Government Printing Office, Washington, D.C. 625-691. Ciesielski, Paul F., and S.W. Wise, Jr. In press. Geologic history of the Maurice Ewing Bank of the Falkland Plateau (southwest Atlantic sector of the southern ocean) based on piston and drill cores. Marine Geology (special issue; D.E. Hayes, editor). Ciesielski, Paul F., W.V. Sliter, F.H. Wind, and S.W. Wise, Jr. 1977. Paleoenvironmental analysis and correlation of a Cretaceous Islas Orcadas core from the Falkland Plateau, Southwest Atlantic. Marine Micropale ontology, 2(1): 27-34. Gombos, Andrew M. 1977. Paleogene and Neogene diatoms from the Falkland Plateau and Malvinas Outer Basin, Deep Sea Drilling Project. In: P.F. Barker, I.W.D. Dalziel, et al., Initial Reports of the Deep Sea Drilling Project, 36. U.S. Government Printing Office, Washington, D.C. 575-688. McCollum, David W. 1975. Antarctic Cenozoic diatoms: Leg 28, Deep Sea Drilling Project. In: L.A. Frakes, D.E. Hayes, et al., Initial Reports of the Deep Sea Drilling Project, 28. U.S. Government Printing Office, Washington, D.C. 515-572. Warnke, Detlef A., P. Bruchhausen, J . LaBrecque, P.F. Ciesielski, 71
BASAL SEDIMENT AGES OF PISTON CORES Latitude(S)
Longitude(l1)
Water Depth (m)
Sample Interval(cm)
40'23.6 39'37.6'
12 1 14 1 16 17 18 20 21 25 27 29 32 33 34 37 38 39
49'23.9 47'49.1 48'5l .2 48'42 .2 47'57 .4 47'46.2' 47'Sl .3' 49'58.8' 49'29.9 49'31 .1' 48'48.l 49'31 .4' 5O'36 .5 SO'58.l 51'36.9' 52'30.4' 52'35 .5 56'34.7' 57'02.7' 57'l1 .6 56'14.O' 55'l1 .6 S5'08.2' 52'41 .3' 52o25.8' 51 '58.4
39'12.9 37'O2.3 36o33.3 35'03.6' 34o59.6 29'28.5' 29'lO.O' 25'54.9' 33'58.6 34'58.2 35'37.6' 36'O2.2' 31 '46.0' 24'39 .9' 27'24.O' 31 '49.5' 27'16.4' 2O'17.2' 23'34.3' 25'29 .6' 30'36.l 30 '26 .4 31 '05.5' 42'O5 .9' 42'lO.S' 42'21 .7'
2090 50 Sandy gravel 3336 800;1109 diatomaceous ooze; diatomaceous mud 3299 c/C gravel 5616 1035; 1138 diatomaceous mud; mud 4895 1167 mud 5087 842; 1006 pelagic clay 5298 1127 muddy, diatomaceous ooze 4712 C/C mud 4535 *SEE NOTE, BELOW 4610 1634; 1664 diatomaceous ooze 5080 1094 diatomaceous mud 4967 1056 diatomaceous ooze 4989 184 mud 4707 696 diatomaceous mud 4440 891; 1689 diatomaceous ooze 4139 1130 diatomaceous ooze 4194 565 diatomaceous mud 3395 C/C *SEE NOTE, BELOW 4639 930; 1079 diatomaceous ooze 5014 1146 diatomaceous ooze 5020 1107 diatomaceous ooze 3504 15 diatomaceous ooze 2933 581 diatomaceous ooze 4623 255 diatomaceous ooze 5073 78; 537 diatomaceous ooze 2782 1006 diatomaceous ooze 3603 1137 muddy, diatomaceous ooze 2694 C/C gravel
40 41 42 43 44 45 46 47 48 49 50 51 52 53
5O'18.2' 5O'OO.7 49'52.1 50'l 3.2 50'l 8.5 50'25 .0 5O'27.8' 5O'32.9' 5O'38 .5 5O'44.1 5O'Sl .5' 5O'57. 3 50o54.7 50'52 .0
43'25.O' 43'34.7' 43'37.8' 44'08.8' 44'31 .7' 44'52.4' 44'57.2' 45'18.4' 46'04.7' 46'2O .2 46'46.1 47'O2.1 46'SO.O' 46o36.6
1605 2189 2621 1 713 1651 1621 1599 1517 1493 1784 2344 2547 2558 2229
54 55 56 57
50'36.O' 5O'38.O 50' 35 .0' SO'34.9
46'23.1 46'39.l 47'27.2' 47'3O. 7'
1856 2255 2637 2525
4
'NOTE:
441 diatomaceous, nannofossil ooze C/C gravel C/C gravel 381; 852 nannofossil ooze 687 nannofossil ooze 474 radiolarian-nanmofossil ooze 303 nannofossil ooze 280 radiolarian, namnofossil ooze 392 diatomaceous, mannofossil ooze 461 nanmofossil , diatomaceous ooze 159 pelagic clay 63 muddy, diatomaceous ooze 133 muddy, diatomaceous ooze 177; 191 diatomaceous ooze; gravelly, Siliceous ooze 275; 365 diatomaceous, nanmofossil ooze 341 diatomaceous, oannofossil ooze 9 manganese nodule with mud 65 radiolarian, diatomaceous mud with manganese
Quaternary Age Early Pliocene Quaternary Early Pliocene Early Pliocene Early Pliocene Quaternary Late Pliocene Quaternary Quaternary Quaternary Quaternary Quaternary Quaternary Quaternary Quaternary Quaternary Early Pliocene Quaternary Quaternary Quaternary Quaternary Quaternary Quaternary Quaternary Quaternary Pliocene with reworked Mesozoic ? micrite Early Miocene Quaternary Late Pliocene Early Oligocene Campani an/Maestri chtian Late Paleocene Late Paleocene Early Miocene Late Miocene Late Miocene Eocene (Early ?) Early Pliocene Early Pliocene Late Miocene Late Miocene Late Miocene Oligocene Early Pliocene
Two piston cores, 0775-9 and -20, remain unopened, and therefore undescribed, due to special handling and sampling requirements of a principal investigator, Dr. Detlef Warnke. Bottom sediment from one of these, 0775-9, is not available for dating at this time. C/C in the sample interval column denotes that dated sample was from the core cutter and/or catcher.
and A. Federaman. 1976. ARA Islas Orcadas cruise 7. Antarctic Journal of the U.S., XI(2): 70-73. Weaver, Fred M. 1976. Late Miocene and Pliocene radiolarian paleobiogeography and biostratigraphy of the southern ocean. Tallahassee, Department of Geology, Florida State University. Ph.D. dissertation (unpublished). 175p.
Deep sea drilling contributions to studies of the evolution of the southern ocean and antarctic glaciation JAMES P. KENNETT
Graduate School of Oceanography University of Rhode Island Kingston, Rhode Island 02881 The world ocean circulation system has exhibited major changes through time as a result of topographic evolution of 72
Sediment Lithology
49'4O.9' 49'27 .3
Wise, Sherwood W., Jr., and F.H. Wind. 1977. Mesozoic and Cenozoic calcareous nannofossils recovered by DSDP leg 36 drilling on the Falkland Plateau, Atlantic sector of the southern ocean. In: P.F. Barker, I.W.D. Daiziel, et al., Initial Reports of the Deep Sea Drilling Proj ect, 36. U.S. Government Printing Office, Washington, D.C. 269-492.
the ocean basins, changing positions of continents, and earth's climatic and glacial evolution especially in the polar regions. Three major elements of paleoceanographic change can be distinguished for the Cenozoic. The first of these is related to the development of the circumantarctic circula tion system as southern land masses moved aside creating unrestricted latitudinal flow; the second is a generally reciprocal breakup of equatorial and lower latitude circula tion as land masses moved across or developed in these regions; the third is related to the development and history of bottom waters of the oceans in response to climatic and glacial events especially in the polar regions. Thus two of the three major elements involved in global Cenozoic paleoceanographic evolution are directly related to events occurring at high latitudes, particularly in the southern hemisphere. The evolution of the southern ocean itself has had a fundamental influence on the development of antarcANTARCTIC JOURNAL
Project. In: P.F. Barker, I.W.D. Dalziel, et al., Initial Reports of the Deep Sea Drilling Project, 36. U.S. Government Printing Office, Washington, D.C. 575-688. Gordon, A.L., D.T. Georgi, and H.W. Taylor. In press. Antarctic polar front zone in the western Scotia Sea - summer I 975.Journal of Physical Oceanography. Leonardi, A., and M. Ewing. 1971. Bathyrnetry chart of the Argentine Basin (map, no scale). In: Physics and Chemistry of the Earth, London, Pergamon Press. 8. McCollum, D.W. 1975. Antarctic Cenozoic diatoms: leg 28, Deep Sea Drilling Project. In L.A. Frakes, D.E. Hayes, et al., Initial Reports of the Deep Sea Drilling Project, 28. U.S. Government Printing Office, Washington, D.C. 515-572. Sclater, T.G., D. Woodroffe, H. Dick, D. Georgi, S.W. Wise, and P. Ciesielski. 1977. Scientific report for Islas Orcadas cruise 11. AntarcticJournalof the U.S., XII(4): 62-65. Warnke, D.A., P. Bruchhausen, J . LaBrecque, P.F. Ciesielski and A. Federman. 1976. ARA Islas Orcadas cruise 7. Antarctic Jour. nalof the U.S., XI(2): 70-73. Weaver, F.M. 1976. Late Miocene and Pliocene radiolarian paleobiogeography and biostratigraphy of the southern ocean. Tallahassee, Department of Geology, Florida State University, Ph.D. Dissertation (unpublished). 175 p. Wise, SW., and F.H. Wind. 1977. Mesozoic and Cenozoic calcareous nannofossils recovered by DSDP leg 36 drilling on the Falkland Plateau, Atlantic sector of the southern ocean. In: P.F. Barker, I.W.D. Dalziel, et al., Initial Reports of the Deep Sea Drilling Project, 36. U.S. Government Printing Office, Washington, D.C. 269-492.
References
Barker, P.F. 1977. Correlations between sites on the Eastern Falkland Plateau by means of seismic reflection profiles, Leg 36, Deep Sea Drilling Project. In: P.F. Barker, I.W.D. Dalziel, et al., Initial Reports of the Deep Sea Drilling Project, 36. U.S. Government Printing Office, Washington, D.C. 971-900. Barker, P.F., I.W.D. Dalziel, D.H. Elliot, C.C. von der Borch, R.W. Thompson, G. Plafker, R.C. Tjalsma, S.W. Wise, M.G. Dinkelman, A.M. Gombos, A. Lonardi, andJ. Tarney. 1977. Initial Reports of the Deep Sea Drilling Project, 36. U.S. Government Printing Office, Washington, D.C. 1080 p. Busen, Karen L., and S.W. Wise. 1977. Silicoflagellate biostratigraphy, Deep Sea Drilling Project leg 36. In: P.F. Barker, I.W.D. Dalziel, et al., Initial Reports of the Deep Sea Drilling Project, 36. U.S. Government Printing Office, Washington, D.C. 697-744. Ciesielski, P.F., 1975. Biostratigraphy and paleoecology of Neogene and Oligocene silicoflagellates from cores recovered during antarctic leg 28, Deep Sea Drilling Project. In: D.E. Hayes, L.A. Frakes, et al., Initial Reports of the Deep Sea Drilling Project, 28. U.S. Government Printing Office, Washington, D.C. 625-691. Ciesielski, P.F. and S.W. Wise. In press. Geologic history of the Maunice Ewing Bank of the Falkland Plateau (Southwest Atlantic section of the southern ocean) based on piston and drill cores. Marine Geology (special issue; D.E. Hayes, editor). aesielski, P.F., W.V. Sliter, F.H. Wind, and S.W. Wise. In press. Paleoenvironmental analysis and correlation of a Cretaceous Islas Orcadas core from the Falkland Plateau, Southwest Atlantic. Marine Micropaleontology, 2. Ciesielski, P.E., W.V. Sliter, F.H. Wind, and S.W. Wise. 1977. A Cretaceous Islas Orcadas core from the Falkland (Malvinas) Plateau, southwest Atlantic. Antarctic Journal of the U. S., XII(4): 65-67. Combos, A . M. 1977. Paleogene and Neogene diatoms from the Falkland Plateau and Malvinas Outer Basin, Deep Sea Drilling 70
Basal sediment ages of Islas Orcadas cruise 7 piston cores PAUL F. CIESIELSKI and SHERWOOD W. WISE, JR.
Antarctic Marine Geology Research Facility Department of Geology Florida State University Tallahassee, Florida 32306
As an aid to other investigators wishing to study ARA Islas Orcadas cores, we present here preliminary basal sediment ages for 45 piston cores taken on cruise 7, the first multidisciplinary cruise (marine geology, physical oceanography, and geophysics) of the ship to the southwest Atlantic sector of the southern ocean. This cruise, which began and ended at Buenos Aires, concentrated on the Falkland (Malvinas) Plateau, the South Georgia Basin, and peripheral areas (Warnke et al. 1976). The table lists piston core numbers, latitude, longitude, water depth, sample interval, age, and sediment lithology of the basal sedimentary unit. Sampling. Fully recovered cores, stored in plastic liners, were sampled within 1 to 6 centimeters of their base; those with disturbed basal sedimentary sequences were sampled above the disturbed sequence as well. For all such cores sampled in this manner, both samples gave similar ages. Seven cores comprise a second group, from which samples ANTARCTIC JOURNAL
48'*
70W 6" 6" srw 50W 4 ° T I 1 1 1 1
44W
46W
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ISLAS ORCADAS 0775 SAMPLE LOCATIONS • PISTON CORE 8 TRIGGER CORE
• PISTON CORE ONLY o ROM DREDGE
55S
032 036--.
•27 -
Islas Orcadas cruise 7 sample locations.
025
FA70MS
o •w 60w _ iw 45W 40w
were taken from material retrieved by the core cutter and/or catcher (c/c). This sediment is stored as bag samples. Laboratory. Smear-slide preparations from each sample were examined for their calcareous nannofossil, diatom, and silicoflagellate contents and were age-dated utilizing the high- latitude biostratigraphic zonations recently summarized by: Calcareous nannofossils: Wise and Wind (1977). Diatoms: McCollum (1975); Gombos (1977); Weaver (1976). Silicoflagellates: Ciesielski (1975); Busen and Wise (1977). Pliocene and Quaternary sedimentary sequences were dated using the diatom biostratigraphic zonation of McCollum (1975), which has been used successfully in the southwest Atlantic by Gombos (1977). Weaver's (1976) modification of the early Pliocene portion of McCollum's diatom zonation was used where possible. The sediment age-dates in the table are preliminary. A number of the determinations are based on examination of only one sample and not on an examination of the entire core. For those cases, it is difficult to detect complicating factors such as reworking or contamination that might lead to an improper age assignment. Investigators planning detailed work on these cores may wish to obtain additional confirmation of the age-dates provided. More detailed age assignments (down to subepoch or biostratigraphic zone) for some of the cruise 7 cores are given in Ciesielski et al. (in press) and Ciesielski and Wise (in press). This research was supported by National Science Foundation grant OPP 74-20109. Operational support by the Argentine Naval Hydrographic Service is gratefully acknowledged. October 1977
30W 25W 2" I3•W
References
Busen, Karen L., and S.W. Wise, Jr. 1977. Silicoflagellate biostratigraphy. Deep Sea Drilling Project Leg 36. In: P.F. Barker, I.W.D. Dalziel, et al., Initial Reports of the Deep Sea Drilling Project, 36. U.S. Government Printing Office, Washington, D.C. 697-744. Cassidy, Dennis S., P.F. Ciesielski, F.A. Kaharoeddin, S.W. Wise and I. Zemmels. 1977. ARA Islas Orcadas cruise 0775 sediment descriptions. Sedimentology Research Laboratory, Department of Geology, Florida State University. Contribution, 45. 76 p. Ciesielski, Paul F. 1975. Biostratigraphy and paleoecology of Neogene and Oligocene silicoflagellates from cores recovered during antarctic leg 28, Deep Sea Drilling Project. In: L.A. Frakes, D.E. Hayes, et al., Initial Reports of the Deep Sea Drilling Project, 28. U.S. Government Printing Office, Washington, D.C. 625-691. Ciesielski, Paul F., and S.W. Wise, Jr. In press. Geologic history of the Maurice Ewing Bank of the Falkland Plateau (southwest Atlantic sector of the southern ocean) based on piston and drill cores. Marine Geology (special issue; D.E. Hayes, editor). Ciesielski, Paul F., W.V. Sliter, F.H. Wind, and S.W. Wise, Jr. 1977. Paleoenvironmental analysis and correlation of a Cretaceous Islas Orcadas core from the Falkland Plateau, Southwest Atlantic. Marine Micropale ontology, 2(1): 27-34. Gombos, Andrew M. 1977. Paleogene and Neogene diatoms from the Falkland Plateau and Malvinas Outer Basin, Deep Sea Drilling Project. In: P.F. Barker, I.W.D. Dalziel, et al., Initial Reports of the Deep Sea Drilling Project, 36. U.S. Government Printing Office, Washington, D.C. 575-688. McCollum, David W. 1975. Antarctic Cenozoic diatoms: Leg 28, Deep Sea Drilling Project. In: L.A. Frakes, D.E. Hayes, et al., Initial Reports of the Deep Sea Drilling Project, 28. U.S. Government Printing Office, Washington, D.C. 515-572. Warnke, Detlef A., P. Bruchhausen, J . LaBrecque, P.F. Ciesielski, 71
BASAL SEDIMENT AGES OF PISTON CORES Latitude(S)
Longitude(l1)
Water Depth (m)
Sample Interval(cm)
40'23.6 39'37.6'
12 1 14 1 16 17 18 20 21 25 27 29 32 33 34 37 38 39
49'23.9 47'49.1 48'5l .2 48'42 .2 47'57 .4 47'46.2' 47'Sl .3' 49'58.8' 49'29.9 49'31 .1' 48'48.l 49'31 .4' 5O'36 .5 SO'58.l 51'36.9' 52'30.4' 52'35 .5 56'34.7' 57'02.7' 57'l1 .6 56'14.O' 55'l1 .6 S5'08.2' 52'41 .3' 52o25.8' 51 '58.4
39'12.9 37'O2.3 36o33.3 35'03.6' 34o59.6 29'28.5' 29'lO.O' 25'54.9' 33'58.6 34'58.2 35'37.6' 36'O2.2' 31 '46.0' 24'39 .9' 27'24.O' 31 '49.5' 27'16.4' 2O'17.2' 23'34.3' 25'29 .6' 30'36.l 30 '26 .4 31 '05.5' 42'O5 .9' 42'lO.S' 42'21 .7'
2090 50 Sandy gravel 3336 800;1109 diatomaceous ooze; diatomaceous mud 3299 c/C gravel 5616 1035; 1138 diatomaceous mud; mud 4895 1167 mud 5087 842; 1006 pelagic clay 5298 1127 muddy, diatomaceous ooze 4712 C/C mud 4535 *SEE NOTE, BELOW 4610 1634; 1664 diatomaceous ooze 5080 1094 diatomaceous mud 4967 1056 diatomaceous ooze 4989 184 mud 4707 696 diatomaceous mud 4440 891; 1689 diatomaceous ooze 4139 1130 diatomaceous ooze 4194 565 diatomaceous mud 3395 C/C *SEE NOTE, BELOW 4639 930; 1079 diatomaceous ooze 5014 1146 diatomaceous ooze 5020 1107 diatomaceous ooze 3504 15 diatomaceous ooze 2933 581 diatomaceous ooze 4623 255 diatomaceous ooze 5073 78; 537 diatomaceous ooze 2782 1006 diatomaceous ooze 3603 1137 muddy, diatomaceous ooze 2694 C/C gravel
40 41 42 43 44 45 46 47 48 49 50 51 52 53
5O'18.2' 5O'OO.7 49'52.1 50'l 3.2 50'l 8.5 50'25 .0 5O'27.8' 5O'32.9' 5O'38 .5 5O'44.1 5O'Sl .5' 5O'57. 3 50o54.7 50'52 .0
43'25.O' 43'34.7' 43'37.8' 44'08.8' 44'31 .7' 44'52.4' 44'57.2' 45'18.4' 46'04.7' 46'2O .2 46'46.1 47'O2.1 46'SO.O' 46o36.6
1605 2189 2621 1 713 1651 1621 1599 1517 1493 1784 2344 2547 2558 2229
54 55 56 57
50'36.O' 5O'38.O 50' 35 .0' SO'34.9
46'23.1 46'39.l 47'27.2' 47'3O. 7'
1856 2255 2637 2525
4
'NOTE:
441 diatomaceous, nannofossil ooze C/C gravel C/C gravel 381; 852 nannofossil ooze 687 nannofossil ooze 474 radiolarian-nanmofossil ooze 303 nannofossil ooze 280 radiolarian, namnofossil ooze 392 diatomaceous, mannofossil ooze 461 nanmofossil , diatomaceous ooze 159 pelagic clay 63 muddy, diatomaceous ooze 133 muddy, diatomaceous ooze 177; 191 diatomaceous ooze; gravelly, Siliceous ooze 275; 365 diatomaceous, nanmofossil ooze 341 diatomaceous, oannofossil ooze 9 manganese nodule with mud 65 radiolarian, diatomaceous mud with manganese
Quaternary Age Early Pliocene Quaternary Early Pliocene Early Pliocene Early Pliocene Quaternary Late Pliocene Quaternary Quaternary Quaternary Quaternary Quaternary Quaternary Quaternary Quaternary Quaternary Early Pliocene Quaternary Quaternary Quaternary Quaternary Quaternary Quaternary Quaternary Quaternary Pliocene with reworked Mesozoic ? micrite Early Miocene Quaternary Late Pliocene Early Oligocene Campani an/Maestri chtian Late Paleocene Late Paleocene Early Miocene Late Miocene Late Miocene Eocene (Early ?) Early Pliocene Early Pliocene Late Miocene Late Miocene Late Miocene Oligocene Early Pliocene
Two piston cores, 0775-9 and -20, remain unopened, and therefore undescribed, due to special handling and sampling requirements of a principal investigator, Dr. Detlef Warnke. Bottom sediment from one of these, 0775-9, is not available for dating at this time. C/C in the sample interval column denotes that dated sample was from the core cutter and/or catcher.
and A. Federaman. 1976. ARA Islas Orcadas cruise 7. Antarctic Journal of the U.S., XI(2): 70-73. Weaver, Fred M. 1976. Late Miocene and Pliocene radiolarian paleobiogeography and biostratigraphy of the southern ocean. Tallahassee, Department of Geology, Florida State University. Ph.D. dissertation (unpublished). 175p.
Deep sea drilling contributions to studies of the evolution of the southern ocean and antarctic glaciation JAMES P. KENNETT
Graduate School of Oceanography University of Rhode Island Kingston, Rhode Island 02881 The world ocean circulation system has exhibited major changes through time as a result of topographic evolution of 72
Sediment Lithology
49'4O.9' 49'27 .3
Wise, Sherwood W., Jr., and F.H. Wind. 1977. Mesozoic and Cenozoic calcareous nannofossils recovered by DSDP leg 36 drilling on the Falkland Plateau, Atlantic sector of the southern ocean. In: P.F. Barker, I.W.D. Daiziel, et al., Initial Reports of the Deep Sea Drilling Proj ect, 36. U.S. Government Printing Office, Washington, D.C. 269-492.
the ocean basins, changing positions of continents, and earth's climatic and glacial evolution especially in the polar regions. Three major elements of paleoceanographic change can be distinguished for the Cenozoic. The first of these is related to the development of the circumantarctic circula tion system as southern land masses moved aside creating unrestricted latitudinal flow; the second is a generally reciprocal breakup of equatorial and lower latitude circula tion as land masses moved across or developed in these regions; the third is related to the development and history of bottom waters of the oceans in response to climatic and glacial events especially in the polar regions. Thus two of the three major elements involved in global Cenozoic paleoceanographic evolution are directly related to events occurring at high latitudes, particularly in the southern hemisphere. The evolution of the southern ocean itself has had a fundamental influence on the development of antarcANTARCTIC JOURNAL
