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200,000 years of mo...
200,000 years of monsoonal history recorded on the lower Bengal Fan - strong response to insolation forcing
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- Weber, Michael E. (författare)
- University of Bonn, Bonn, Germany
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- Lantzsch, Hendrik (författare)
- University of Bremen, Bremen, Germany
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- Dekens, Petra (författare)
- San Francisco State University, San Francisco, USA
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- Das, Supriyo K. (författare)
- Presidency University, Kolkata, India
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- Reilly, Brendan T. (författare)
- Oregon State University, Corvallis, USA
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- Martos, Yasmina M. (författare)
- NASA Goddard Space Flight Center, Greenbelt, USA; The University of Maryland, College Park, USA
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- Meyer-Jacob, Carsten, 1984- (författare)
- Umeå universitet,Institutionen för ekologi, miljö och geovetenskap
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- Agrahari, Sandip (författare)
- Presidency University, Kolkata, India
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- Ekblad, Alf, 1957- (författare)
- Örebro universitet,Institutionen för naturvetenskap och teknik
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- Titschack, Jurgen (författare)
- University of Bremen, Bremen, Germany
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- Holmes, Beth (författare)
- San Francisco State University, San Francisco, USA
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- Wolfgramm, Philipp (författare)
- University of Bremen, Bremen, Germany
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(creator_code:org_t)
- Elsevier, 2018
- 2018
- Engelska.
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Ingår i: Global and Planetary Change. - : Elsevier. - 0921-8181 .- 1872-6364. ; 166, s. 107-119
- Relaterad länk:
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https://urn.kb.se/re...
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https://doi.org/10.1...
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https://urn.kb.se/re...
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Abstract
Ämnesord
Stäng
- We conducted a multidisciplinary study to provide the stratigraphic and palaeoclimatic context of monsoonal rainfall dynamics and their responses to orbital forcing for the Bay of Bengal. Using sediment lightness we established an age model at orbital resolution for International Ocean Discovery Programme (IODP) Core U1452C-1H that covers the last 200 ka in the lower Bengal Fan. The low-resolution delta O-18 of G. sacculifer is consistent with global delta O-18 records, at least for major glacial-to-interglacial transitions. The variability of total organic carbon, total nitrogen, and the delta C-13 composition of organic matter indicate the marine origin of organic matter. Marine primary productivity likely increased during insolation minima, indicative for an enhanced NE monsoon during glacials and stadials. Pristine insolation forcing is also documented for wet-bulk density, red green color variability, and grain-size variations, indicating that darker and coarser-grained material deposited at higher sedimentation rates during insolation minima. Stronger NE monsoon likely amplified ocean-atmosphere interactions over the Indian Ocean, leading to stronger upwelling through shoaling the thermocline, and higher delivery of sediment to the Bay of Bengal due to higher soil erosion on land. In addition, lower glacial and stadial sea levels as well as stronger westward surface circulation favored delivery of coarser-grained fluvial material to the lower Bengal Fan. At the same time the stronger NE monsoon might have increased the aeolian supply. Total inorganic carbon, the Ca/Ti ratio, and biogenic silica vary dominantly on obliquity frequencies, suggesting mobilization and transport of lithogenic material primarily during lowered sea levels and/or higher influence of the Northern Hemisphere westerlies on the dust transport from the Tibetan Plateau. The close resemblance of sediment lightness and the climate record of Antarctic ice cores over multiple glacial cycles indicate close relationship between high southern latitude and tropical Asian climate through shifts in position of the Intertropical Convergence Zone. The Bengal Fan monsoonal record shows very clear and strict responses to insolation forcing in the lower part from -200 ka to the Younger Toba Tuff during Marine Isotope Stage (MIS) 7 - 5, and less distinct response patterns after deposition of the ash during MIS 4- 2, consistent with low-amplitude changes in insolation.
Ämnesord
- NATURVETENSKAP -- Geovetenskap och miljövetenskap -- Geologi (hsv//swe)
- NATURAL SCIENCES -- Earth and Related Environmental Sciences -- Geology (hsv//eng)
- NATURVETENSKAP -- Geovetenskap och miljövetenskap -- Naturgeografi (hsv//swe)
- NATURAL SCIENCES -- Earth and Related Environmental Sciences -- Physical Geography (hsv//eng)
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Weber, Michael E ...
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Lantzsch, Hendri ...
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Dekens, Petra
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Das, Supriyo K.
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Reilly, Brendan ...
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Martos, Yasmina ...
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visa fler...
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Meyer-Jacob, Car ...
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Agrahari, Sandip
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Ekblad, Alf, 195 ...
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Titschack, Jurge ...
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Holmes, Beth
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Wolfgramm, Phili ...
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NATURVETENSKAP
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