Geochemistry of sandstones from the Neoproterozoic Jinshanzhai Formation in northern Anhui Province, China: Provenance, weathering and tectonic setting  

作　　者：SUN Linhua GUI Herong CHEN Song 

机构地区：[1]School of Earth Science and Engineering, Suzhou University

出　　处：《Chinese Journal Of Geochemistry》2013年第1期95-103,共9页中国地球化学学报

基　　金：financially supported jointly by the National Natural Science Foundation of China(41173106);the Outstanding Young Talent Foundation of Colleges and Universities in Anhui Province(2010SQRL190);the Foundation of Scientific Platform in Suzhou University(2010YKF30)

摘　　要：Sandstones from the Neoproterozoic Jinshanzhai Formation in northern Anhui Province, China, were analyzed for major oxides and trace elements to infer their provenance, the intensity of paleo-weathering of their source rocks and the depositional tectonic setting. Diagrams of (SiO2/20)-(Na2O+K2O)-(MgO+TiO2+FeO*), TiO2-Ni, Th-Hf-Co, Hf-La/Th and some ratios of elements indicate that felsic rocks constitute the source rocks in the provenance. The values of Chemical Index of Alteration (CIA) are low, which are considered to be affected by K-metasomatism. Whereas the high CIW (Chemical Index of Weathering) values indicate intensive weathering of the source material. Plots of sandstones on bivariate and triangle discriminant diagrams, as well as ICV (Index of Compositional Variation) values revealed that they were deposited on a passive continental margin or in an intra-plate basin. Our recent study, in combination with previous studies and the research progress of the Rodinia super continent, demonstrated that the convergence and extension of the Rodinia super continent were preserved by twice extension as expressed by petrological variation of the southeastern margin of the North China Craton (NCC) during the Neoproterozoic.Sandstones from the Neoproterozoic Jinshanzhai Formation in northern Anhui Province, China, were analyzed for major oxides and trace elements to infer their provenance, the intensity of paleo-weathering of their source rocks and the depositional tectonic setting. Diagrams of （SiO2/20）-（Na20＋K20）-（MgO＋TiO2＋FeO^＊）, TiO2-Ni, Th-Hf-Co, Hf-La/Th and some ratios of elements indicate that felsic rocks constitute the source rocks in the provenance. The values of Chemical Index of Alteration （CIA） are low, which are considered to be affected by K-metasomatism. Whereas the high CIW （Chemical Index of Weathering） values indicate intensive weathering of the source material. Plots of sandstones on bivariate and triangle discriminant diagrams, as well as ICV （Index of Com- positional Variation） values revealed that they were deposited on a passive continental margin or in an intra-plate basin. Our recent study, in combination with previous studies and the research progress of the Rodinia super continent, demonstrated that the convergence and extension of the Rodinia super continent were preserved by twice extension as expressed by petrological variation of the southeastern margin of the North China Craton （NCC） during the Neoproterozoic.

关 键 词：沉积构造背景 中国北方 新元古代 地球化学特征 安徽省 RODINIA超大陆 砂岩 耐候性 

分 类 号：P512[天文地球—地质学]