SHRIMP U-Pb zircon age of tuff at the bottom of the Lower Cambrian Niutitang Formation,Zunyi,South China  

作　　者：ZHOU MingZhong LUO TaiYi LI ZhengXiang ZHAO Hui LONG HanSheng YANG Yong 

机构地区：[1]State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002 China [2]The Institute of Geoscience Research, Department of Applied Geology, Curtin University of Technology, GPO Box U1987, Perth WA 6845, Australia [3]Graduate University of Chinese Academy of Sciences, Beijing 100049, China

出　　处：《Chinese Science Bulletin》2008年第4期576-583,共8页

基　　金：Supported by the National Natural Science Foundation of China (Grant No.40672053)

摘　　要：A SHRIMP U-Pb zircon geochronology study of the tuff at the bottom of the Lower Cambrian Niutitang Formation at Songlin,Zunyi,South China yielded a mean 206Pb/238U age of 518±5 Ma.It is significantly younger than the Re-Os ages of 537―542 Ma for the overlying polymetallic Ni-Mo-PGE-rich layer in the basal Niutitang Formation at Songlin,suggesting that the Re-Os ages might represent that of the original magma chamber for the Ni-Mo-PGE-rich layer rather than the formation age of the strata.The intra-basinal stratigraphic correlation also implies that the absolute age of the Chengjiang biota should be younger than 518±5 Ma.Our new result,together with the SHRIMP U-Pb zircon age for the K-bentonite in the Zhongyicun member of the Zhujiaqing Formation at the Meishucun section,Yunnan Province,provides a temporal constraint for the Lower Cambrian of the Yangtze Platform in South China.A SHRIMP U-Pb zircon geochronology study of the tuff at the bottom of the Lower Cambrian Niutitang Formation at Songlin, Zunyi, South China yielded a mean ^206Pb/^238U age of 518±5 Ma. It is significantly younger than the Re-Os ages of 537--542 Ma for the overlying polymetallic Ni-Mo-PGE-rich layer in the basal Niutitang Formation at Songlin, suggesting that the Re-Os ages might represent that of the original magma chamber for the Ni-Mo-PGE-rich layer rather than the formation age of the strata. The intra-basinal stratigraphic correlation also implies that the absolute age of the Chengjiang biota should be younger than 518±5 Ma. Our new result, together with the SHRIMP U-Pb zircon age for the K-bentonite in the Zhongyicun member of the Zhujiaqing Formation at the Meishucun section, Yunnan Province, provides a temporal constraint for the Lower Cambrian of the Yangtze Platform in South China.

关 键 词：早寒武纪 凝灰岩 中国 遵义 地质年代学 

分 类 号：P534.1[天文地球—古生物学与地层学] P597[天文地球—地质学]