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Is the Simultaneous Onset of the Florida, East Australia, and Indian Ocean Currents Related to Himalayan tectonics?
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  • Gregor Eberli,
  • Christian Betzler,
  • Anna Ling Hui Mee,
  • Dick Kroon,
  • Silvia Spezzaferri
Gregor Eberli
University of Miami

Corresponding Author:[email protected]

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Christian Betzler
Geologisch-Pal. Institut
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Anna Ling Hui Mee
University of Miami
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Dick Kroon
University of Edinburgh
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Silvia Spezzaferri
University of Fribourg
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Abstract

Carbonate drift deposits in the Santaren Channel, on the Marion Plateau and in the Inner Sea of the Maldives were cored and dated by ODP and IODP expeditions. The ages based on biostratigraphy of these drifts are 11.4 Ma (Marion Drift), 12.3 Ma (Santaren Drift) and 12.9 Ma (Maldives Inner Sea), indicating a near simultaneous onset of the Florida, East Australia and Indian Ocean Currents that are all part of the global ocean current system. The Himalayan tectonics started with the collision of the Indian continent with Asia about ~50 Ma ago and continues today. The uplift of the Himalaya and Tibetan Plateau was not steady and not consistent across the mountain belt. The uplift of the southern and central Tibetan Plateau occurred from 40–35 Ma, at the northern Tibetan plateau at approximately 25–20 Ma, and at the northeastern to eastern Tibetan plateau at ~15 Ma. Significant increases in altitude of the entire Tibetan plateau are thought to have occurred about 10–8 Ma agoor more recently, some 3 myrs after the onset of the modern Indian Ocean monsoon-driven circulation system that is dated at 12.9 Ma. This sudden onset or intensification is puzzling in light of the continuous uplift of the Himalaya and Tibetan Plateau. If a linkage between tectonics and climate exists, the uplift must have stepped over a threshold that caused the climate to change dramatically. The near simultaneous onset of the global ocean circulation and the intensification of the monsoon is strong evidence that a combination of factors caused the sudden climate change. It is likely that onset of the intense monsoon is the combined result of the tectonic configuration, consisting of the Himalayan uplift but also the closing of the Tethyan seaway, and progressive glaciation on Antarctica.