Germanium/silica ratio and trace element composition of Early Cambrian siliceous rocks in Keping:implications for the siliceous rocks'formation and paleoenvironment interpretations

作     者：Zixuan Guan Shibiao Deng Peixian Liu Yiqiu Jin Xingchun Cao Zixuan Guan;Shibiao Deng;Peixian Liu;Yiqiu Jin;Xingchun Cao

作者机构：MOE Key Laboratory od Orogenic Belts and Crustal EvolutionSchool of Earth and Space SciencePeking UniversityBeijing 100871China Research Institute of Petroleum Exploration and DevelopmentCNPCBeijing 100083China 

出 版 物：《Acta Geochimica》 (地球化学学报（英文）)

年 卷 期：2020年第39卷第6期

页      面：797-810页

核心收录：

学科分类：070903[理学-古生物学与地层学(含：古人类学)] 0709[理学-地质学] 070901[理学-矿物学、岩石学、矿床学] 07[理学] 

基　　金：National Key Basic Research Program of China(973 Program No.2012CB214801).We also thank Prof.Dong Lin at Peking University for the help in the ICP-OES analyses 

主　　题：Siliceous rocks Trace elements Ge/Si ratio Tarim Basin 

摘      要：This study used the germanium/silica(Ge/Si)ratios,together with rare earth elements and other trace elements to infer the siliceous source and sedimentary environment of the siliceous rocks located at the bottom of Yuertusi Formation in Northwestern Tarim Basin,Keping,*** studies have shown that this siliceous rock stratum formed at the edge of the carbonate platform on the continental *** suggest that these siliceous rocks were formed by hydrothermal activity,but some still draw different *** the silicon source and depositional environment of these siliceous rocks would help us learn the processes of environmental changes and the causes of biological explosions during this *** value of germanium/silica ratios of these siliceous rocks is from 0.15 to 0.37 pmol/mol and much lower than above 10|imol/mol values in siliceous rocks that are known formed by hydrothermal *** samples are rich in HREE,which differ from hydrothermal siliceous rocks that are rich in *** samples lack hydrothermal related *** these features show that the source of these siliceous rocks siliceous is not hydrothermal flu *** samples Ce/Ce*range from 0.88 to 1,and Th/U ratios range from 0.01 to *** features suggest these siliceous rocks were formed in an anoxic *** all the evidence,we conclude that the siliceous rock stratum at the bottom of the Lower Cambrian Yuertusi Formation in northwest Tarim ***,was formed in anoxic seawater at the edge of the carbonate platform on the continental *** silicon source is seawater instead of hydrothermal fluid.