现代地质2017，Vol.31Issue(3)：574-586,13.
武威盆地石炭系泥页岩元素地球化学特征及意义
Element Geochemical Characteristics of Carboniferous Shale in Wuwei Basin and Its Significance
摘要
Abstract
By comprehensively analyzing the major element,microelement and rare earth element of carboniferous shale samples which from Chouniugou Formation and Yanghugou Formation in Wuwei Basin and its surrounded area,and discussing the significance of the result for provenance,weathering denudation degree and tectonic setting.The research founded that the element characteristics of Carboniferous shale in Wuwei Basin is as follaws:(1) The major element is rich in SiO2 and Al2O3,and loss of MgO and Fe2O3.(2) The upper crust standardization of microelements is regularly change.U,Th and Cr are rich,and Ba,Nb and Zr are loss.(3) The distribution pattern of rare earth element (REE) is about the same as upper crust,which is right deviation in overall,rich in LREE,stabilize in HREE and negative anomaly Eu.The three findings show that the source rock is mainly from upper crust.Weathering index (CIA) value of 68.81-90.17,with a mean of 83.9,reflects the research area suffered moderate weathering;the average CIA value of Chouniugou section and Hongshuipu section is 84.1 and 83.51 in order which shows that the weathering degree in the western study area isrelatively stronger than that in the eastern.The index of weathering(CIA) is relatively high,which indicates the study area is suffered from medium weathering.Analysis of the diagram of major element ratio,microelement and rare earth element indicates the source rock of the study area is feldspathic-quartz,mainly intermediate to acidic granite and alkali basalt.On the basis of discrimination diagrams of SiO2-K2O/Na2O,La-Th-Sc,Th -Co-Zr/10 and abnormal value of Ce,the tectonic setting is considered to be a passive continental margin.By contrastive analysis of the east and the west of the study area,we found that Chouniugou section in the west of the Basin has a mixed source from Longxi ancient land and Alashan ancient land,whereas Hongshuipu section in the east of the Basin has a single source from Longxi ancient land.关键词
武威盆地/石炭纪/元素地球化学/构造背景/物源/风化作用Key words
Wuwei Basin/Carboniferous period/geochemistry of element/tectonic setting/provenance/weathering分类
能源科技引用本文复制引用
彭媛媛,康志宏,李伟奇,韩慧宇,谭龙..武威盆地石炭系泥页岩元素地球化学特征及意义[J].现代地质,2017,31(3):574-586,13.基金项目
中国地质调查局“河西走廊重点盆地烃源岩调查”(12120115002901-04). （12120115002901-04）
