Secular and orbital-scale variability of equatorial Indian Ocean summer monsoon winds during the late Miocene
<p>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 varianc...
| Main Authors: | , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2022-04-01
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| Series: | Climate of the Past |
| Online Access: | https://cp.copernicus.org/articles/18/713/2022/cp-18-713-2022.pdf |
| _version_ | 1818395037793255424 |
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| author | C. T. Bolton E. Gray E. Gray W. Kuhnt A. E. Holbourn J. Lübbers K. Grant K. Tachikawa G. Marino G. Marino E. J. Rohling E. J. Rohling A.-C. Sarr N. Andersen |
| author_facet | C. T. Bolton E. Gray E. Gray W. Kuhnt A. E. Holbourn J. Lübbers K. Grant K. Tachikawa G. Marino G. Marino E. J. Rohling E. J. Rohling A.-C. Sarr N. Andersen |
| author_sort | C. T. Bolton |
| collection | DOAJ |
| description | <p>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<span class="inline-formula"><sub>2</sub></span> 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 (<span class="inline-formula"><1</span> 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.</p> |
| first_indexed | 2024-12-14T06:10:44Z |
| format | Article |
| id | doaj.art-07ddf86a8b374f04a3bb3177edf84c47 |
| institution | Directory Open Access Journal |
| issn | 1814-9324 1814-9332 |
| language | English |
| last_indexed | 2024-12-14T06:10:44Z |
| publishDate | 2022-04-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Climate of the Past |
| spelling | doaj.art-07ddf86a8b374f04a3bb3177edf84c472022-12-21T23:14:09ZengCopernicus PublicationsClimate of the Past1814-93241814-93322022-04-011871373810.5194/cp-18-713-2022Secular and orbital-scale variability of equatorial Indian Ocean summer monsoon winds during the late MioceneC. T. Bolton0E. Gray1E. Gray2W. Kuhnt3A. E. Holbourn4J. Lübbers5K. Grant6K. Tachikawa7G. Marino8G. Marino9E. J. Rohling10E. J. Rohling11A.-C. Sarr12N. Andersen13Aix Marseille Univ, CNRS, IRD, INRAE, Coll France, CEREGE, Aix-en-Provence, 13545, Aix-en-Provence, FranceAix Marseille Univ, CNRS, IRD, INRAE, Coll France, CEREGE, Aix-en-Provence, 13545, Aix-en-Provence, Francenow at: School of Environment, Earth and Ecosystem Sciences, The Open University, Milton Keynes MK7 6AA, UKInstitute of Geosciences, University of Kiel, 24118 Kiel, GermanyInstitute of Geosciences, University of Kiel, 24118 Kiel, GermanyInstitute of Geosciences, University of Kiel, 24118 Kiel, GermanyResearch School of Earth Sciences, Australian National University, Canberra ACT 2601, AustraliaAix Marseille Univ, CNRS, IRD, INRAE, Coll France, CEREGE, Aix-en-Provence, 13545, Aix-en-Provence, FranceResearch School of Earth Sciences, Australian National University, Canberra ACT 2601, AustraliaCentro de Investigación Mariña, Universidade de Vigo, GEOMA, Palaeoclimatology Lab, Vigo, 36310, SpainResearch School of Earth Sciences, Australian National University, Canberra ACT 2601, AustraliaOcean and Earth Science, University of Southampton, Southampton SO14 3ZH, UKAix Marseille Univ, CNRS, IRD, INRAE, Coll France, CEREGE, Aix-en-Provence, 13545, Aix-en-Provence, FranceLeibniz Laboratory for Radiometric Dating and Stable Isotope Research, University of Kiel, 24118 Kiel, Germany<p>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<span class="inline-formula"><sub>2</sub></span> 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 (<span class="inline-formula"><1</span> 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.</p>https://cp.copernicus.org/articles/18/713/2022/cp-18-713-2022.pdf |
| spellingShingle | C. T. Bolton E. Gray E. Gray W. Kuhnt A. E. Holbourn J. Lübbers K. Grant K. Tachikawa G. Marino G. Marino E. J. Rohling E. J. Rohling A.-C. Sarr N. Andersen Secular and orbital-scale variability of equatorial Indian Ocean summer monsoon winds during the late Miocene Climate of the Past |
| title | 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_short | 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 |
| url | https://cp.copernicus.org/articles/18/713/2022/cp-18-713-2022.pdf |
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