A major reorganization of Asian climate by the early Miocene

	A major reorganization of Asian climate by the early Miocene
	Guo, Z. T.1; Sun, B.1,2,3; Zhang, Z. S.1,4; Peng, S. Z.1; Xiao, G. Q.5; Ge, J. Y.5; Hao, Q. Z.1; Qiao, Y. S.1; Liang, M. Y.1; Liu, J. F.1
刊名	CLIMATE OF THE PAST
	2008
卷号	4 期号:3 页码:153-174
ISSN号	1814-9324
文献子类	Review
英文摘要	The global climate system experienced a series of drastic changes during the Cenozoic. In Asia, these include the climate transformation from a zonal pattern to a monsoon-dominated pattern, the disappearance of typical subtropical aridity, and the onset of inland deserts. Despite major advances in the last two decades in characterizing and understanding these climate phenomena, disagreements persist relative to the timing, behaviors and underlying causes. This paper addresses these issues mainly based on two lines of evidence. First, we compiled newly collected data from geological indicators of the Cenozoic environment in China as paleoenvironmental maps of ten intervals. In confirming the earlier observation that a zonal climate pattern was transformed into a monsoonal one, the maps within the Miocene indicate that this change was achieved by the early Miocene, roughly consistent with the onset of loess deposition in China. Although a monsoon-like regime would have existed in the Eocene, it was restricted to tropical-subtropical regions. The latitudinal oscillations of the climate zones during the Paleogene are likely attributable to the imbalance in evolution of polar ice-sheets between the two hemispheres. Secondly, we examine the relevant depositional and soil forming processes of the Miocene loess-soil sequences to determine the circulation characteristics with emphasis on the early Miocene. Continuous eolian deposition in the middle reaches of the Yellow River since the early Miocene firmly indicates the formation of inland deserts, which have been constantly maintained during the past 22 Ma. Grain-size gradients between loess sections indicate northerly dust-carrying winds from northern sources, a clear indication of an Asian winter monsoon system. Meanwhile, well-developed Luvisols show evidence that moisture from the oceans reached northern China. This evidence shows the coexistence of two kinds of circulations, one from the ocean carrying moisture and another from the inland deserts transporting dust. The formation of the early Miocene paleosols resulted from interactive soil forming and dust deposition processes in these two seasonally alternating monsoonal circulations. The much stronger development of the early Miocene soils compared to those in the Quaternary loess indicates that summer monsoons were either significantly stronger, more persistent through the year, or both. These lines of evidence indicate a joint change in circulation and inland aridity by the early Miocene and suggest a dynamic linkage of them. Our recent sensitivity tests with a general circulation model, along with relevant geological data, suggest that the onset of these contrasting wet/dry responses, as well as the change from the "planetary" subtropical aridity pattern to the "inland" aridity pattern, resulted from the combined effects of Tibetan uplift and withdrawal of the Paratethys seaway in central Asia, as suggested by earlier experiments. The spreading of South China Sea also helped to enhance the south-north contrast of humidity. The Miocene loess record provides a vital insight that these tectonic factors had evolved by the early Miocene to a threshold sufficient to cause this major climate reorganization in Asia.
WOS关键词	CHINESE LOESS PLATEAU ; ATMOSPHERIC CARBON-DIOXIDE ; LATE CENOZOIC UPLIFT ; NORTHERN TIBETAN PLATEAU ; LAND-SEA DISTRIBUTION ; PAST 800,000 YEARS ; WIND-BLOWN ORIGIN ; GRAIN-SIZE ; GENERAL-CIRCULATION ; MONSOON CLIMATE
WOS研究方向	Geology ; Meteorology & Atmospheric Sciences
语种	英语
出版者	COPERNICUS GESELLSCHAFT MBH
WOS记录号	WOS:000259647700002
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/70088]
专题	中国科学院地质与地球物理研究所
通讯作者	Guo, Z. T.
作者单位	1.Chinese Acad Sci, Inst Geol & Geophys, Key Lab Cenozo Geol & Environm, Beijing 100029, Peoples R China 2.Shandong Inst, Jinan 250013, Peoples R China 3.Lab Geol Sci, Jinan 250013, Peoples R China 4.Chinese Acad Sci, Inst Atmospher Phys, Nansen Zhu Int Res Ctr, Beijing 100029, Peoples R China 5.Chinese Acad Sci, Inst Earth Environm, State Key Lab Loess & Quaternary Geol, Xian 710075, Peoples R China
推荐引用方式 GB/T 7714	Guo, Z. T.,Sun, B.,Zhang, Z. S.,et al. A major reorganization of Asian climate by the early Miocene[J]. CLIMATE OF THE PAST,2008,4(3):153-174.
APA	Guo, Z. T..,Sun, B..,Zhang, Z. S..,Peng, S. Z..,Xiao, G. Q..,...&Wei, J. J..(2008).A major reorganization of Asian climate by the early Miocene.CLIMATE OF THE PAST,4(3),153-174.
MLA	Guo, Z. T.,et al."A major reorganization of Asian climate by the early Miocene".CLIMATE OF THE PAST 4.3(2008):153-174.