Variation and Mechanism of Paleoclimate in the Last Glaciation in the Tropic Northern Leizhou Peninsula in South China
详细信息
- 责任者：Cao Jiayuan (School of Geographical Science ; South China Normal University ; Guangzhou 510631 ; China) ; Zhong Wei
- 刊名：Acta Geologica Sinica
- 出版年：2013
- 卷期：87(8)
- 关键词：末次冰期 ; last glacial age ; 古气候 ; paleoclimate ; 雷州半岛 ; Leizhou Peninsula
- 页码：p.1179-1192
- 图表：6 illus., 1 table, 77 refs.
- 分类号：1400
- issnNo：ISSN0001-5717
- isbnNo：CN11-1951/P
摘要
Based on the analyses of bulk organic δ13C for the Wushan and the Xialu peat cores,as well as a fluvial or swamp composed sequence,the Quanshui section from the north of Leizhou Peninsula,we reconstructed the history of climate changes between 48.0 and 10 cal ka BP in the north tropic region in South China.On basis of comparison with the multi-proxy climatic records such as the loss on ignition (LOI),the content of organic matter (OM),the degree of humification (HD),and the Low field magnetic susceptibility (χlf) of three profiles,we interpret that more negative bulk organic δ13C values would suggest wetter and warmer conditions,implying a strengthening of the East Asian (EA) summer monsoon,whereas less negative δ13C values indicate drier and cooler conditions,suggesting a weakening of the EA summer monsoon.A warm and wet period occurred between 48.0 and 28 cal ka BP.A climate shift occurred at 22 (or 20) cal ka BP,and the driest and coldest period occurred between 18.0 and 16.0 cal ka BP,which indicate a weak EA summer monsoon and may be related to the last glacial maximum (LGM).After 12.0 cal ka BP,the climate changed towards wetter and warmer conditions.From 48.0 to 10.0 cal ka BP,several short positive δ13Corg excursions indicate the expansion of C4 plants or the C3 plants characterized by more positive δ13Corg value.These excursions shows a similarity with the Heinrich events and other cold millennial-scale oscillations evidenced from a Greenland ice core and the Chinese stalagmite record.We also demonstrate that the variations of climate reflected by bulk δ13Corg records show an inverse correlation with the South American monsoon in the South Hemisphere.We deduce that the solar radiation,as well as the solar radiation-driven the shift of the intertropical convergence zone (ITCZ),may have played a role in the climate changes in the Last Glaciation in north tropic China.The migration of ITCZ may have caused meridional asymmetry in the Hadley circulation,and would change meridional moisture transport.This will make the climate changes in northern low latitudes show an inverse correlation with southern low latitudes.Besides,high latitudes of the southern hemisphere may play a key role in the climate changes of Leizhou Peninsula through the mechanism of "push" or "pull".
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