Advances in Earth Science
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Tuo Shouting,Liu Zhifei,Cheng Xinrong,Zhao Quanhong
Tuo Shouting,Liu Zhifei,Cheng Xinrong,Zhao Quanhong . The Earliest Oligocene Carbonate Record in South Atlantic (ODP Site 1263)[J]. Advances in Earth Science, 2006, 21(8): 800-805.
he first continent-wide Antarctic ice sheet formed in the earliest Oligocene, during which the Earth underwent a great change from a non-glaciated planet to a polar glaciated planet. Recent investigations suggested that the mechanism of this climate transition has a close relationship with variations of ocean carbon reservoir and atmospheric CO2. The grain size variations of the carbonate ooze at ODP Site 1263 in South Atlantic revealed that a very strong carbonate dissolution event happened in the Earliest Oligocene. Leading the heaviest foraminiferal δ18O by 100 ka, the carbonate dissolution event started earlier than formation of the Antarctic ice sheet. The carbonate dissolution consumes lots of atmospheric CO2 and then transports the atmospheric CO2 into deep sea through the function of calcium pump. It could force and speed up the global cooling, and then the permanent ice sheet appeared on the eastern Antarctic.