准噶尔盆地南缘中二叠统页岩矿物学和地球化学特征及地质意义  

The Mineralogy and Geochemistry of the middle Permian Lucaogou Formation Shales in the Southern Junggar Basin,Xinjiang Province and Its Geological significance

作　　者：涂其军 王刚 Tu Qijun;Wang Gang(Xinjiang Institute of Geological Survey,Urumqi,Xinjiang,830000,China)

机构地区：[1]新疆维吾尔自治区地质调查院,新疆乌鲁木齐830000

出　　处：《新疆地质》2018年第4期455-462,共8页Xinjiang Geology

基　　金：新疆维吾尔自治区地质调查院新疆准噶尔盆地南缘页岩气资源远景调查项目(12120114031901)资助

摘　　要：基于对准噶尔盆地南缘中二叠统芦草沟组页岩矿物学和地球化学的研究,着重探讨了芦草沟组页岩的地球化学组分、源区母岩性质和构造背景。结果表明:芦草沟组页岩矿物以石英、伊利石和伊蒙混层为主,含少量斜长石和铁白云石;对比上地壳元素丰度,页岩相对富集P_2O_5,V,Ni和Cu,其他元素含量相对亏损或类似于上地壳丰度,P_2O_5的富集归因于同期火山灰的输入;矿物组合及源岩判别指标揭示源区母岩以酸性岩为主,但与上地壳相比,其含更多的铁镁质组分和更少的长英质组分,最可能为类似于英云闪长岩的岩石;芦草沟组页岩具生物成因过量的SiO_2的存在,导致页岩比母岩(英云闪长岩)具更高的SiO_2/Al_2O_3比值;二叠纪源区处于大陆岛弧构造背景之下。The mineralogy and geochemistry of the Middle Permian Lucaogou Formation shales in the southern Junggar basin,Xinjiang,have been performed to investigate its geochemical composition and to infer parent rock nature and tectonic setting.These results show that mineral matter is dominated by quartz,illite and illite/smectite layers,and to a lesser extent plagioclase and ankerite;in comparison to elemental abundance of the Upper Continental Crust(UCC),these analysed shales are enriched in P2O5,V,Ni and Cu,the remaining elements are depleted or are similar to corresponding element abundance of UCC,and the enrichment of P2O5 is ascribed to the synsedimentary volcanic ash input;The provenance of these investigated shales is mainly felsic igneous rock which contains more mafic constituents and less felsic ones than that of UCC and most likely is tonalite;these shales contain large proportions of SiO2 derived from biogenic origin,which has led to significantly higher SiO2/Al2O3 ratios than that of tonalite;The tectonic setting of sediment-source region is predominated by Continental Island Arc setting in the Permian.

关 键 词：准噶尔盆地 芦草沟组 矿物学 地球化学 

分 类 号：P534.46[天文地球—古生物学与地层学] P619.227[天文地球—地质学]