Indonesian Throughflow variability on sub-orbital timescales during Marine Isotopes Stages (MIS) 2 and 3
Final Report Abstract
Sea surface, upper thermocline and bottom water isotope and planktonic Mg/Ca temperature records (60–100 year temporal resolution) spanning marine isotope stage 3 (MIS3, 24–62 ka B.P.) from two cores (MD01-2378, 121°47.270’E and 13°04.950’S; 1783 m water depth and SO-185 18460, 8°47.386’ S, 128°38.485’ E, 1875 m water depth) reveal new inside in the dynamics of the Indonesian Throughflow (ITF) outflow in the Timor Sea. Stable isotopes and Mg/Ca of the near-surface-dwelling planktonic foraminifer Globigerinoides ruber (white) and the upper thermocline–dwelling Pulleniatina obliquiloculata reveal rapid changes in the thermal structure of the upper ocean during Heinrich events. Thermocline warming and increased upper thermocline δ18Oseawater (related to increased salinity) during Heinrich events 3, 4, and 5 reflect weakening of the relatively cool and fresh thermocline flow and reduced freshwater export from the North Pacific and Indonesian Seas to the tropical Indian Ocean. The evolution of the ITF outflow during MIS3 was related to global slowdown in thermohaline circulation during Heinrich events triggered by Northern Hemisphere cooling, decreased freshwater export from the Java Sea into the Indonesian Throughflow during periods of lowered sea level, and insolation-related changes in the Australian monsoon with associated migration of hydrological fronts between Indian Ocean and Indonesian Throughflow thermocline water masses. The Nd-isotope signature in the Timor Sea does not show major fluctuations associated with Heinrich Events. This is in accordance with the Nd-isotope patterns in present-day upper thermocline water masses, which mainly reflect the contribution of individual outflow passages rather than total ITF mass transport.
Publications
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2007. Climate variability on centennial timescales in the Timor Sea during Marine Isotope Stages 2 and 3. Geophysical Research Abstracts, Vol. 9, 05476, 2007
Duerkop, A., R. Zuraida, A. Holbourn, W. Kuhnt, D. Nuernberg & N. Andersen
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2007. Timor Sea surface and subsurface temperature variability on centennial timescales during MIS 2-3. Geophysical Research Abstracts, Vol. 9, 06617, 2007
Zuraida, R., A. Duerkop, D. Nuernberg, A. Holbourn & W. Kuhnt
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(2008). Centennial-scale climate variability in the Timor Sea during Marine Isotope Stage 3. Marine Micropaleontology, 66, 208-221
Dürkop, A., Holbourn, A., Kuhnt, W., Zuraida, R., Andersen, N., Grootes, P.
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2008. Indonesian Throughflow variability over the last 140 kyr: Temperature and precipitation proxy records from the Timor Sea. AGU Fall Meeting San Francisco
Kuhnt, W., Holbourn, A., Xu, J., Bolliet, T., Duerkop, A., Nuernberg, D., Zuraida, R., Andersen, N.
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(2009). Evidence for Indonesian Throughflow slow-down during Heinrich Events 3-5. Paleoceanography, 24, PA2205
Zuraida, R., Holbourn, A., Nürnberg, D., Kuhnt, W., Dürkop, A. & Erichsen, A.
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2010. Climate Variability in the Eastern Indian Ocean during Marine Isotope Stage 3: High-Resolution Proxy Studies from the Timor Sea. Dissertation, Mathematisch-Naturwissenschaftliche Fakultät, Christian-Albrechts-Universität zu Kiel, 114 pp.
Dürkop, A.
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2010. Indonesian Throughflow Variability on Sub-Orbital Timescales during Marine Isotope Stage 3: Geochemical Aspects. Dissertation, Mathematisch-Naturwissenschaftliche Fakultät, Christian-Albrechts-Universität zu Kiel, 207 pp.
Zuraida, R.
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2011. Intertropical Convergence Zone migration during Marine Isotope Stage 3. IUGG 2011 General Assembly 2011, Melbourne, Australia. P04_1PP124
Zuraida, R., W. Kuhnt, A. Holbourn, A. Duerkop, D. Nuernberg
