Record of Holocene glacial oscillations in Bransfield Basin as revealed by siliceous microfossil assemblages
Two gravity cores, Gebra-1 and Gebra-2 from the central and eastern basins of Bransfield Strait, West Antarctica, consist mainly of hemipelagic, laminated muds with black layers rich in sand-sized volcanic ash. Micropalaeontological (diatoms and radiolarians) and geochemical (organic and inorganic)...
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Cambridge University Press (CUP)
1998
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Online Access: | http://dx.doi.org/10.1017/s0954102098000364 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0954102098000364 |
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crcambridgeupr:10.1017/s0954102098000364 2024-10-13T14:02:57+00:00 Record of Holocene glacial oscillations in Bransfield Basin as revealed by siliceous microfossil assemblages Bárcena, M. Angeles Gersonde, Rainer Ledesma, Santiago Fabrés, Joan Calafat, Antonio M. Canals, Miquel Sierro, F. Javier Flores, Jose A. 1998 http://dx.doi.org/10.1017/s0954102098000364 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0954102098000364 en eng Cambridge University Press (CUP) https://www.cambridge.org/core/terms Antarctic Science volume 10, issue 3, page 269-285 ISSN 0954-1020 1365-2079 journal-article 1998 crcambridgeupr https://doi.org/10.1017/s0954102098000364 2024-09-18T04:02:14Z Two gravity cores, Gebra-1 and Gebra-2 from the central and eastern basins of Bransfield Strait, West Antarctica, consist mainly of hemipelagic, laminated muds with black layers rich in sand-sized volcanic ash. Micropalaeontological (diatoms and radiolarians) and geochemical (organic and inorganic) analyses, together with radiometric dating (U/Th, 14 C and 210 Pb) have been performed on both cores. AMS analyses on Total Organic Carbon yielded a 14 C-age older than expected, 2810 yr BP for the core top of Gebra-1 and 2596 yr BP for Gebra-2. The downcore pattern of ages indicates a sedimentation rate of 130 cm kyr 1 for Gebra-1 and 160 cm kyr 1 for Gebra-2 210 Pb anomalies suggest the core top of Gebra-1 is present-day sediment. The diatom and radiolarian assemblages are related to the sequence of neoglacial events over the last three millennia. The recent significant reduction in Chaetoceros resting spores is interpreted as a reduction in palaeoproductivity. The progressive increase in sea-ice taxa for the last three millennia may indicate a cooling trend. Greater sea-ice coverage during the coldest neoglacial events in the Bransfield Basin, as well as in the Weddell Sea and Bellingshausen Sea, is documented by increases in sea-ice taxa and reductions in Thalassiosira antarctica/ T. scotia resting spores, Fragilariopsis kerguelensis , the Lithomelissa group and the “circumpolar” group of radiolarians. For these periods, we postulate a restricted communication between the Weddell Sea, Bellingshausen Sea and Bransfield basin. The millenial-scale changes are overprinted by a high frequency cyclicity at about 200–300 yrs, which might be related to the 200–yrs solar cycle. Article in Journal/Newspaper Antarc* Antarctic Science Antarctica Bellingshausen Sea Bransfield Strait Sea ice Weddell Sea West Antarctica Cambridge University Press Weddell Sea West Antarctica Bellingshausen Sea Bransfield Strait Weddell Antarctic Science 10 3 269 285 |
institution |
Open Polar |
collection |
Cambridge University Press |
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crcambridgeupr |
language |
English |
description |
Two gravity cores, Gebra-1 and Gebra-2 from the central and eastern basins of Bransfield Strait, West Antarctica, consist mainly of hemipelagic, laminated muds with black layers rich in sand-sized volcanic ash. Micropalaeontological (diatoms and radiolarians) and geochemical (organic and inorganic) analyses, together with radiometric dating (U/Th, 14 C and 210 Pb) have been performed on both cores. AMS analyses on Total Organic Carbon yielded a 14 C-age older than expected, 2810 yr BP for the core top of Gebra-1 and 2596 yr BP for Gebra-2. The downcore pattern of ages indicates a sedimentation rate of 130 cm kyr 1 for Gebra-1 and 160 cm kyr 1 for Gebra-2 210 Pb anomalies suggest the core top of Gebra-1 is present-day sediment. The diatom and radiolarian assemblages are related to the sequence of neoglacial events over the last three millennia. The recent significant reduction in Chaetoceros resting spores is interpreted as a reduction in palaeoproductivity. The progressive increase in sea-ice taxa for the last three millennia may indicate a cooling trend. Greater sea-ice coverage during the coldest neoglacial events in the Bransfield Basin, as well as in the Weddell Sea and Bellingshausen Sea, is documented by increases in sea-ice taxa and reductions in Thalassiosira antarctica/ T. scotia resting spores, Fragilariopsis kerguelensis , the Lithomelissa group and the “circumpolar” group of radiolarians. For these periods, we postulate a restricted communication between the Weddell Sea, Bellingshausen Sea and Bransfield basin. The millenial-scale changes are overprinted by a high frequency cyclicity at about 200–300 yrs, which might be related to the 200–yrs solar cycle. |
format |
Article in Journal/Newspaper |
author |
Bárcena, M. Angeles Gersonde, Rainer Ledesma, Santiago Fabrés, Joan Calafat, Antonio M. Canals, Miquel Sierro, F. Javier Flores, Jose A. |
spellingShingle |
Bárcena, M. Angeles Gersonde, Rainer Ledesma, Santiago Fabrés, Joan Calafat, Antonio M. Canals, Miquel Sierro, F. Javier Flores, Jose A. Record of Holocene glacial oscillations in Bransfield Basin as revealed by siliceous microfossil assemblages |
author_facet |
Bárcena, M. Angeles Gersonde, Rainer Ledesma, Santiago Fabrés, Joan Calafat, Antonio M. Canals, Miquel Sierro, F. Javier Flores, Jose A. |
author_sort |
Bárcena, M. Angeles |
title |
Record of Holocene glacial oscillations in Bransfield Basin as revealed by siliceous microfossil assemblages |
title_short |
Record of Holocene glacial oscillations in Bransfield Basin as revealed by siliceous microfossil assemblages |
title_full |
Record of Holocene glacial oscillations in Bransfield Basin as revealed by siliceous microfossil assemblages |
title_fullStr |
Record of Holocene glacial oscillations in Bransfield Basin as revealed by siliceous microfossil assemblages |
title_full_unstemmed |
Record of Holocene glacial oscillations in Bransfield Basin as revealed by siliceous microfossil assemblages |
title_sort |
record of holocene glacial oscillations in bransfield basin as revealed by siliceous microfossil assemblages |
publisher |
Cambridge University Press (CUP) |
publishDate |
1998 |
url |
http://dx.doi.org/10.1017/s0954102098000364 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0954102098000364 |
geographic |
Weddell Sea West Antarctica Bellingshausen Sea Bransfield Strait Weddell |
geographic_facet |
Weddell Sea West Antarctica Bellingshausen Sea Bransfield Strait Weddell |
genre |
Antarc* Antarctic Science Antarctica Bellingshausen Sea Bransfield Strait Sea ice Weddell Sea West Antarctica |
genre_facet |
Antarc* Antarctic Science Antarctica Bellingshausen Sea Bransfield Strait Sea ice Weddell Sea West Antarctica |
op_source |
Antarctic Science volume 10, issue 3, page 269-285 ISSN 0954-1020 1365-2079 |
op_rights |
https://www.cambridge.org/core/terms |
op_doi |
https://doi.org/10.1017/s0954102098000364 |
container_title |
Antarctic Science |
container_volume |
10 |
container_issue |
3 |
container_start_page |
269 |
op_container_end_page |
285 |
_version_ |
1812819395610673152 |