SHRIMP zircon age for a K-bentonite in the top of the Laobao Formation at the Pingyin section, Guizhou, South China

	SHRIMP zircon age for a K-bentonite in the top of the Laobao Formation at the Pingyin section, Guizhou, South China
	MingZhong Zhou; TaiYi Luo; ShiRong Liu; ZhiKuan Qian; LeCai Xing
通讯作者	LUO Taiyi
	2013
发表期刊	Science China Earth Sciences
卷号	56 期号:10 页码:1677-1687
摘要	The Lower Cambrian on the Yangtze Platform in South China (internationally equivalent to the Nerreneuvian and 2nd series of the Cambrian) is valuable for understanding the early evolution of life, the global biogeochemical circles, and the major changes of the ocean. In particular, a precise radiometric calibration of the Lower Cambrian of this region is a critical realm in its multidisciplinary studies. A SHRIMP U-Pb geochronology study of the K-bentonite in the topmost Laobao Formation at the Pingyin section, Guizhou, South China yielded an age of 536 +/- 5 Ma (MSWD = 0.75), suggesting that the K-bentonite here can be correlated with the intensely studied K-bentonite within the middle Zhongyicun Member (Bed 5) of the Zhujiaqing Formation at the Meishucun section in Yunnan. Such a regional correlation result reveals that the Bed 5 K-bentonite also extends into deeper-water environments rather than being deposited merely in the shallow platform interior of the Yangtze Platform. The age of the K-bentonite at the Pingyin section also implies that its overlying polymetallic Ni-Mo layer should be younger than 536 +/- 5 Ma. Hence the previous placement of the Precambrian/Cambrian boundary at this layer is inappropriate. Combined with the results of stratigraphic correlations, it is suggested that the K-bentonites in the middle Zhongyicun Member of the Zhujiaqing Formation (or the equivalents) and the base of the Shiyantou Formation (or its equivalents), together with the polymetallic Ni-Mo layer, serve as three important marker beds. Their self-consistent radiometric ages have established an improved geochronologic framework for the Lower Cambrian in South China.
关键词	Laobao Formation K-bentonite U-pb Geochronology Niutitang Formation Polymetallic Ni-mo Layer
学科领域	矿床地球化学
收录类别	SCI
语种	英语
文献类型	期刊论文
条目标识符	http://ir.gyig.ac.cn/handle/352002/5004
专题	矿床地球化学国家重点实验室_矿床地球化学国家重点实验室_期刊论文矿床地球化学国家重点实验室
推荐引用方式 GB/T 7714	MingZhong Zhou,TaiYi Luo,ShiRong Liu,et al. SHRIMP zircon age for a K-bentonite in the top of the Laobao Formation at the Pingyin section, Guizhou, South China[J]. Science China Earth Sciences,2013,56(10):1677-1687.
APA	MingZhong Zhou,TaiYi Luo,ShiRong Liu,ZhiKuan Qian,&LeCai Xing.(2013).SHRIMP zircon age for a K-bentonite in the top of the Laobao Formation at the Pingyin section, Guizhou, South China.Science China Earth Sciences,56(10),1677-1687.
MLA	MingZhong Zhou,et al."SHRIMP zircon age for a K-bentonite in the top of the Laobao Formation at the Pingyin section, Guizhou, South China".Science China Earth Sciences 56.10(2013):1677-1687.

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