安徽肥西中生代碎屑岩地球化学特征及其对物源制约

位于合肥盆地南部安徽肥西地区的中生代地层，包括防虎山组、园筒山组和周公山组，主要由砂岩组成。虽然初步研究表明物源主要来自大别造山带，但是，进一步限制物源区类型、建立和大别山造山带构造单元之间的对应关系、查清大别山造山带和华北陆块作为物源在研究区的影响范围，具有重要地质意义。本文根据砂岩主元素、REE和微量元素研究表明，研究区砂岩主要是杂砂岩、岩屑砂岩和长石砂岩，主元素含量比较接近晚元古代造山带砂岩。砂岩非常一致的REE模型，基本显示了同一的物源和相同的构造背景。REE和微量元素特征显示肥西地区中生代砂岩物源主要为佛子岭群和卢镇关群，大别杂岩的影响比较局限，更没有来自华北克拉通的物质。同时，在中生代，大别山造山带的物源没有影响到华北陆块南部沉积。Th-Co-Zr／10和Th-Sc-Zr／10判别图以及微量元素比值都支持碎屑岩的物源形成于大陆岛弧构造背景，这不仅验证了已有的结论，同时也揭示了在造山带周缘盆地中碎屑岩地球化学特征具有构造背景的继承性。

Geochemistry of Mesozoic detrital rocks and its constraints on provenance in Feixi area, Anhui provence

The Mesozoic strata developing in the south of Hefei basin, Feixi area of Anhui Province, comprising Fanghushan, Yuantongshan and zhougongshan Formations, are primarily composed of sandstones. Though their source rocks may be chienfly from the Dabie Orogenic Belt on basis of previous studies, there is important implication that exactly limit the types of the source rocks, thus constructing corresponding relations between sedimentary sequences and various tectonic units, and find out the extent of actual influence of the provenances of Dabie Orogenic Belt and Huabei Landmas. Based on petrochemical analysis of the sandstones, they consist mainly of greywacke, lithic arenite and arkose, and major element concentrations of the sandstones fall in with Late Proterozoic orogenic sandstones. The unanimous REE diagrams of the sandstones suggest that they were formed from the same source rocks and tectonic setting. The data of REE and trace elements indicate that the source rocks were mainly composed of Fuziling and Luzhengguan Groups, limited for Dabie complex and no Huabei Landmass matter. Meanwhile, Dabie orogenic belt might have not provided material for the Mesozoic deposition of the south of Huabei Landmass. Th-Co-Zr/10 and Th-Sc-Zr/10 diagrams and trace element ratios suggest that the provenance attributes to continental island-arc, which examines the former conclusion and brings to light the tectonic setting inherit of petrochemistry for detrital rocks formed in peripheral basins.