Changes in Southern Ocean circulation in late Oligocene to early Miocene time
Benthic stable isotopic measurements from four ODP Leg 189 sites, in and near the Tasmanian Gateway, link existing southern high latitude records from the Oligocene. Bulk sediment isotopic analyses at Sites 1170-1172 present the first moderate resolution, high latitude “planktic” late Oligocene to e...
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2005
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Online Access: | http://hdl.handle.net/10278/3711505 https://doi.org/10.1029/151GM11 https://agupubs.onlinelibrary.wiley.com/doi/10.1029/151GM11 |
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ftuniveneziairis:oai:iris.unive.it:10278/3711505 2024-04-14T08:02:10+00:00 Changes in Southern Ocean circulation in late Oligocene to early Miocene time Pfuhl, H. A. McCave, I. N. Schellenberg, S. A. Ferretti P. Exon, N.F. Kennett, J.P. Malone, M.J Malone, M.J. Pfuhl, H. A. Mccave, I. N. Schellenberg, S. A. Ferretti, P. 2005 STAMPA http://hdl.handle.net/10278/3711505 https://doi.org/10.1029/151GM11 https://agupubs.onlinelibrary.wiley.com/doi/10.1029/151GM11 eng eng Blackwell Publishing Ltd. info:eu-repo/semantics/altIdentifier/isbn/978-111866621-0 info:eu-repo/semantics/altIdentifier/isbn/978-087590416-0 ispartofbook:The Cenozoic southern ocean: tectonics, sedimentation and climate change between Australia and Antarctica volume:151 firstpage:173 lastpage:189 numberofpages:17 serie:GEOPHYSICAL MONOGRAPH alleditors:Exon, N.F.; Kennett, J.P.; Malone, M.J. http://hdl.handle.net/10278/3711505 doi:10.1029/151GM11 info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-21344451521 https://agupubs.onlinelibrary.wiley.com/doi/10.1029/151GM11 info:eu-repo/semantics/closedAccess Geology Structural Antarctic Ocean Paleoclimatology Cenozoic Climatic changes Climate Marine sediments Settore GEO/02 - Geologia Stratigrafica e Sedimentologica info:eu-repo/semantics/bookPart 2005 ftuniveneziairis https://doi.org/10.1029/151GM11 2024-03-21T18:09:06Z Benthic stable isotopic measurements from four ODP Leg 189 sites, in and near the Tasmanian Gateway, link existing southern high latitude records from the Oligocene. Bulk sediment isotopic analyses at Sites 1170-1172 present the first moderate resolution, high latitude “planktic” late Oligocene to early Miocene (-28-21 Ma) data. Stable isotopes and records of carbonate content suggest similar surface hydrography for southern Sites 1170-1171, and strongly reduced offsets at Site 1172 to the north, following-22.8 Ma. Benthic δ18O values at these sites show low variability prior to earliest Miocene cooling. Greater offsets of 1170-1172 benthic δ18O from southern Kerguelen Plateau values, continuing until 25.4 Ma, cast doubt on hypotheses of earlier development of circum-Antarctic circulation and therefore deep opening of the Drake Passage. The data also suggest that Southern Hemisphere temperatures in this area were relatively warm throughout the late Oligocene, consistent with published Mg/Ca temperature reconstructions for bottom waters. The global ice-volume signal of the early Oligocene (Oi-1) records a brief event which did not lead to a permanent ice sheet, but high δ18O values at Maud Rise (Sites 689-690) continuing into the late Oligocene suggest an increase in Antarctic Bottom Water production in the Weddell Sea. Near complete similarity of surface hydrographic conditions at Sites 1170-1172 following-22.8 Ma suggests this as a youngest date for full development of the Antarctic Circumpolar Current. Book Part Antarc* Antarctic Antarctic Ocean Drake Passage Ice Sheet Southern Ocean Weddell Sea Università Ca’ Foscari Venezia: ARCA (Archivio Istituzionale della Ricerca) Antarctic Southern Ocean The Antarctic Weddell Sea Kerguelen Drake Passage Weddell Antarctic Ocean Maud Rise ENVELOPE(3.000,3.000,-66.000,-66.000) 173 189 |
institution |
Open Polar |
collection |
Università Ca’ Foscari Venezia: ARCA (Archivio Istituzionale della Ricerca) |
op_collection_id |
ftuniveneziairis |
language |
English |
topic |
Geology Structural Antarctic Ocean Paleoclimatology Cenozoic Climatic changes Climate Marine sediments Settore GEO/02 - Geologia Stratigrafica e Sedimentologica |
spellingShingle |
Geology Structural Antarctic Ocean Paleoclimatology Cenozoic Climatic changes Climate Marine sediments Settore GEO/02 - Geologia Stratigrafica e Sedimentologica Pfuhl, H. A. McCave, I. N. Schellenberg, S. A. Ferretti P. Changes in Southern Ocean circulation in late Oligocene to early Miocene time |
topic_facet |
Geology Structural Antarctic Ocean Paleoclimatology Cenozoic Climatic changes Climate Marine sediments Settore GEO/02 - Geologia Stratigrafica e Sedimentologica |
description |
Benthic stable isotopic measurements from four ODP Leg 189 sites, in and near the Tasmanian Gateway, link existing southern high latitude records from the Oligocene. Bulk sediment isotopic analyses at Sites 1170-1172 present the first moderate resolution, high latitude “planktic” late Oligocene to early Miocene (-28-21 Ma) data. Stable isotopes and records of carbonate content suggest similar surface hydrography for southern Sites 1170-1171, and strongly reduced offsets at Site 1172 to the north, following-22.8 Ma. Benthic δ18O values at these sites show low variability prior to earliest Miocene cooling. Greater offsets of 1170-1172 benthic δ18O from southern Kerguelen Plateau values, continuing until 25.4 Ma, cast doubt on hypotheses of earlier development of circum-Antarctic circulation and therefore deep opening of the Drake Passage. The data also suggest that Southern Hemisphere temperatures in this area were relatively warm throughout the late Oligocene, consistent with published Mg/Ca temperature reconstructions for bottom waters. The global ice-volume signal of the early Oligocene (Oi-1) records a brief event which did not lead to a permanent ice sheet, but high δ18O values at Maud Rise (Sites 689-690) continuing into the late Oligocene suggest an increase in Antarctic Bottom Water production in the Weddell Sea. Near complete similarity of surface hydrographic conditions at Sites 1170-1172 following-22.8 Ma suggests this as a youngest date for full development of the Antarctic Circumpolar Current. |
author2 |
Exon, N.F. Kennett, J.P. Malone, M.J Malone, M.J. Pfuhl, H. A. Mccave, I. N. Schellenberg, S. A. Ferretti, P. |
format |
Book Part |
author |
Pfuhl, H. A. McCave, I. N. Schellenberg, S. A. Ferretti P. |
author_facet |
Pfuhl, H. A. McCave, I. N. Schellenberg, S. A. Ferretti P. |
author_sort |
Pfuhl, H. A. |
title |
Changes in Southern Ocean circulation in late Oligocene to early Miocene time |
title_short |
Changes in Southern Ocean circulation in late Oligocene to early Miocene time |
title_full |
Changes in Southern Ocean circulation in late Oligocene to early Miocene time |
title_fullStr |
Changes in Southern Ocean circulation in late Oligocene to early Miocene time |
title_full_unstemmed |
Changes in Southern Ocean circulation in late Oligocene to early Miocene time |
title_sort |
changes in southern ocean circulation in late oligocene to early miocene time |
publisher |
Blackwell Publishing Ltd. |
publishDate |
2005 |
url |
http://hdl.handle.net/10278/3711505 https://doi.org/10.1029/151GM11 https://agupubs.onlinelibrary.wiley.com/doi/10.1029/151GM11 |
long_lat |
ENVELOPE(3.000,3.000,-66.000,-66.000) |
geographic |
Antarctic Southern Ocean The Antarctic Weddell Sea Kerguelen Drake Passage Weddell Antarctic Ocean Maud Rise |
geographic_facet |
Antarctic Southern Ocean The Antarctic Weddell Sea Kerguelen Drake Passage Weddell Antarctic Ocean Maud Rise |
genre |
Antarc* Antarctic Antarctic Ocean Drake Passage Ice Sheet Southern Ocean Weddell Sea |
genre_facet |
Antarc* Antarctic Antarctic Ocean Drake Passage Ice Sheet Southern Ocean Weddell Sea |
op_relation |
info:eu-repo/semantics/altIdentifier/isbn/978-111866621-0 info:eu-repo/semantics/altIdentifier/isbn/978-087590416-0 ispartofbook:The Cenozoic southern ocean: tectonics, sedimentation and climate change between Australia and Antarctica volume:151 firstpage:173 lastpage:189 numberofpages:17 serie:GEOPHYSICAL MONOGRAPH alleditors:Exon, N.F.; Kennett, J.P.; Malone, M.J. http://hdl.handle.net/10278/3711505 doi:10.1029/151GM11 info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-21344451521 https://agupubs.onlinelibrary.wiley.com/doi/10.1029/151GM11 |
op_rights |
info:eu-repo/semantics/closedAccess |
op_doi |
https://doi.org/10.1029/151GM11 |
container_start_page |
173 |
op_container_end_page |
189 |
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1796313061597904896 |