闽西南下三叠统溪口组硅质岩的地球化学特征及构造意义  

Geochemistry and tectonic significance of the Lower Triassic Xikou Formation silicalite in SW Fujian,China

作　　者：王果胜[1] 马文璞[1] 朱卫平[1] 

机构地区：[1]中国地质大学地球科学与资源学院,北京100083

出　　处：《成都理工大学学报（自然科学版）》2007年第5期543-547,共5页Journal of Chengdu University of Technology: Science & Technology Edition

基　　金：国家自然科学基金资助项目(40572129)

摘　　要：闽西南下三叠统溪口组中的硅质岩SiO2含量的变化范围为57%~68%,Si/Al=3.4~5.7,远远低于纯硅岩的Si/Al（80~1 400）,表明这些硅质岩中含较高比例陆源泥质沉积物。硅质岩样品w（Al2O3）/w（Al2O3＋Fe2O3）=0.61~0.79,w（Lan）/w（Ybn）值介于1.38~1.75间,w（Ce）/w（Ce＊）=0.87~0.93,w（Lan）/w（Cen）=1.14~1.43,表明这些硅质岩形成于大陆边缘环境。这一结论与大田、漳平一线相当于当时陆坡下部位置的判别存在矛盾,可能的解释是这些硅质岩形成于另一侧的大陆边缘。Major and trace elements are presented in the Lower Triassic Xikou Formation silicalite of SW Fujian, China. These silicalite samples show relatively low SiO2 （57%~68%） and Si/Al ratios （3.4~ 5.7）. These indicate that they are muddy silicalite containing high and variable contents of politic detritus. Geochemically, they are characterized by ω（Al2O3 ）/ω（Al2O3 ＋ Fe2O3 ）=0. 61- 0.79, ω（Lan）/ω（Ybn）= 1.38~1.75, shale-normalized ω（Ce）/ω（Ce^＋）=0.87~0.93, ω（LaN）/ ω（CeN）=1. 14~1.43, resembling those of silicalite formed in the continental margin regimes. The conclusion is not agree with the view of Datian and Zhangping areas located at the continental slope then. The other explanation is that this silicalite formed in another continental margin regime.

关 键 词：硅质岩 地球化学 溪口组 闽西南 

分 类 号：P588.244[天文地球—岩石学]