Secular and orbital-scale variability of equatorial Indian Ocean summer monsoon winds during the late Miocene
In the modern northern Indian Ocean, biological productivity is intimately linked to near-surface oceanographic dynamics forced by the South Asian, or Indian, monsoon. In the late Pleistocene, this strong seasonal signal is transferred to the sedimentary record in the form of strong variance in the...
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ftdoajarticles:oai:doaj.org/article:07ddf86a8b374f04a3bb3177edf84c47 2023-05-15T16:41:18+02:00 Secular and orbital-scale variability of equatorial Indian Ocean summer monsoon winds during the late Miocene C. T. Bolton E. Gray W. Kuhnt A. E. Holbourn J. Lübbers K. Grant K. Tachikawa G. Marino E. J. Rohling A.-C. Sarr N. Andersen 2022-04-01T00:00:00Z https://doi.org/10.5194/cp-18-713-2022 https://doaj.org/article/07ddf86a8b374f04a3bb3177edf84c47 EN eng Copernicus Publications https://cp.copernicus.org/articles/18/713/2022/cp-18-713-2022.pdf https://doaj.org/toc/1814-9324 https://doaj.org/toc/1814-9332 doi:10.5194/cp-18-713-2022 1814-9324 1814-9332 https://doaj.org/article/07ddf86a8b374f04a3bb3177edf84c47 Climate of the Past, Vol 18, Pp 713-738 (2022) Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 article 2022 ftdoajarticles https://doi.org/10.5194/cp-18-713-2022 2022-12-31T04:59:05Z In the modern northern Indian Ocean, biological productivity is intimately linked to near-surface oceanographic dynamics forced by the South Asian, or Indian, monsoon. In the late Pleistocene, this strong seasonal signal is transferred to the sedimentary record in the form of strong variance in the precession band (19–23 kyr), because precession dominates low-latitude insolation variations and drives seasonal contrast in oceanographic conditions. In addition, internal climate system feedbacks (e.g. ice-sheet albedo, carbon cycle, topography) play a key role in monsoon variability. Little is known about orbital-scale monsoon variability in the pre-Pleistocene, when atmospheric CO 2 levels and global temperatures were higher. In addition, many questions remain open regarding the timing of the initiation and intensification of the South Asian monsoon during the Miocene, an interval of significant global climate change that culminated in bipolar glaciation. Here, we present new high-resolution ( <1 kyr) records of export productivity and sediment accumulation from International Ocean Discovery Program Site U1443 in the southernmost part of the Bay of Bengal spanning the late Miocene (9 to 5 million years ago). Underpinned by a new orbitally tuned benthic isotope stratigraphy, we use X-ray fluorescence-derived biogenic barium variations to discern productivity trends and rhythms. Results show strong eccentricity-modulated precession-band productivity variations throughout the late Miocene, interpreted to reflect insolation forcing of summer monsoon wind strength in the equatorial Indian Ocean. On long timescales, our data support the interpretation that South Asian monsoon winds were already established by 9 Ma in the equatorial sector of the Indian Ocean, with no apparent intensification over the latest Miocene. Article in Journal/Newspaper Ice Sheet Directory of Open Access Journals: DOAJ Articles Indian Climate of the Past 18 4 713 738 |
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Open Polar |
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Directory of Open Access Journals: DOAJ Articles |
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ftdoajarticles |
language |
English |
topic |
Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 |
spellingShingle |
Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 C. T. Bolton E. Gray W. Kuhnt A. E. Holbourn J. Lübbers K. Grant K. Tachikawa G. Marino E. J. Rohling A.-C. Sarr N. Andersen Secular and orbital-scale variability of equatorial Indian Ocean summer monsoon winds during the late Miocene |
topic_facet |
Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 |
description |
In the modern northern Indian Ocean, biological productivity is intimately linked to near-surface oceanographic dynamics forced by the South Asian, or Indian, monsoon. In the late Pleistocene, this strong seasonal signal is transferred to the sedimentary record in the form of strong variance in the precession band (19–23 kyr), because precession dominates low-latitude insolation variations and drives seasonal contrast in oceanographic conditions. In addition, internal climate system feedbacks (e.g. ice-sheet albedo, carbon cycle, topography) play a key role in monsoon variability. Little is known about orbital-scale monsoon variability in the pre-Pleistocene, when atmospheric CO 2 levels and global temperatures were higher. In addition, many questions remain open regarding the timing of the initiation and intensification of the South Asian monsoon during the Miocene, an interval of significant global climate change that culminated in bipolar glaciation. Here, we present new high-resolution ( <1 kyr) records of export productivity and sediment accumulation from International Ocean Discovery Program Site U1443 in the southernmost part of the Bay of Bengal spanning the late Miocene (9 to 5 million years ago). Underpinned by a new orbitally tuned benthic isotope stratigraphy, we use X-ray fluorescence-derived biogenic barium variations to discern productivity trends and rhythms. Results show strong eccentricity-modulated precession-band productivity variations throughout the late Miocene, interpreted to reflect insolation forcing of summer monsoon wind strength in the equatorial Indian Ocean. On long timescales, our data support the interpretation that South Asian monsoon winds were already established by 9 Ma in the equatorial sector of the Indian Ocean, with no apparent intensification over the latest Miocene. |
format |
Article in Journal/Newspaper |
author |
C. T. Bolton E. Gray W. Kuhnt A. E. Holbourn J. Lübbers K. Grant K. Tachikawa G. Marino E. J. Rohling A.-C. Sarr N. Andersen |
author_facet |
C. T. Bolton E. Gray W. Kuhnt A. E. Holbourn J. Lübbers K. Grant K. Tachikawa G. Marino E. J. Rohling A.-C. Sarr N. Andersen |
author_sort |
C. T. Bolton |
title |
Secular and orbital-scale variability of equatorial Indian Ocean summer monsoon winds during the late Miocene |
title_short |
Secular and orbital-scale variability of equatorial Indian Ocean summer monsoon winds during the late Miocene |
title_full |
Secular and orbital-scale variability of equatorial Indian Ocean summer monsoon winds during the late Miocene |
title_fullStr |
Secular and orbital-scale variability of equatorial Indian Ocean summer monsoon winds during the late Miocene |
title_full_unstemmed |
Secular and orbital-scale variability of equatorial Indian Ocean summer monsoon winds during the late Miocene |
title_sort |
secular and orbital-scale variability of equatorial indian ocean summer monsoon winds during the late miocene |
publisher |
Copernicus Publications |
publishDate |
2022 |
url |
https://doi.org/10.5194/cp-18-713-2022 https://doaj.org/article/07ddf86a8b374f04a3bb3177edf84c47 |
geographic |
Indian |
geographic_facet |
Indian |
genre |
Ice Sheet |
genre_facet |
Ice Sheet |
op_source |
Climate of the Past, Vol 18, Pp 713-738 (2022) |
op_relation |
https://cp.copernicus.org/articles/18/713/2022/cp-18-713-2022.pdf https://doaj.org/toc/1814-9324 https://doaj.org/toc/1814-9332 doi:10.5194/cp-18-713-2022 1814-9324 1814-9332 https://doaj.org/article/07ddf86a8b374f04a3bb3177edf84c47 |
op_doi |
https://doi.org/10.5194/cp-18-713-2022 |
container_title |
Climate of the Past |
container_volume |
18 |
container_issue |
4 |
container_start_page |
713 |
op_container_end_page |
738 |
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1766031732317880320 |