安徽宿松地区中二叠统栖霞组上升流相烃源岩地球化学特征

下扬子区栖霞组普遍发育与碳酸盐岩共生的硅质沉积，关于硅质沉积成因的讨论认识不一。从上升流成因的角度对安徽宿松地区中二叠统栖霞组进行了野外观察和室内分析，发现研究区出露的上升流岩相类型主要为燧石条带、硅质细纹层、硅质岩及泥晶生物碎屑灰岩等。根据其岩相组合特征将该地区上升流相划分为2个亚相，4个微相。通过对16个样品的有机地化分析，认为各上升流相烃源岩的有机质类型大致为Ⅱ-Ⅲ型，成熟度为成熟一高成熟，总体上看，生烃潜量与有机质丰度呈正相关，综合评价认为，研究区栖霞组上升流相有效烃源岩为硅质薄层和臭灰岩中燧石条带。根据常量元素、微量元素分析认为该区硅质沉积为上升流成因，而原生生物或生物化学成因是上升流成因的一种类型，研究区上升流成因类型样品Al2O3含量均在2％以内，且与SiO2相关性不强。利用V／（V＋Ni）、V／Cr比值研究认为，研究区栖霞组上升流沉积是在浅海斜坡含氧一贫氧过渡环境下沉积的，相比较而言，硅质薄层微相还原程度相对较高。

Geochemistry Features of Up-current Facies Source Rocks from Qixia Formation of Middle Permian in the Susong Area of Anhui Province

Carbonate rocks siliceous deposits were prevalently developed in the Qixia Formation of Lower Yangtze Area.The discussion on the reason of the siliceous deposits was different.Though the study of field observation and laboratory analysis for the Qixia Formation of Middle Permian in the Susong Area of Anhui Province from the aspect of up-current,it was found out that the types of the up-current lithofacies were mainly chert strips,fine siliceous lamina,siliceous rocks and micritic bioclastic limestone.According to the features of the lithofacies combinations,it was divided into 2subfacies and 4up-current micro-facies.Though the organic geochemistry analysis on the 16samples,it was considered that the types of the organic matter of the up-current micro-facies source rocks were roughly divided into TypeⅡ,Ⅲ,the maturity is maturity-high maturity,in general,potential of hydrocarbon generation amount was positive correlation with organic matter abundance,comprehensive evaluation of effective up-current facies source rocks of Qixia Formation was siliceous thin layer and the chert strip in stinkstone in the area.According to the analysis on the macro-element and trace-element,it is considered that the reason of the up-current is siliceous deposit,however,the other reason of the up-current is protista or biochemistry.The content of Al 2 O 3 in the up-current is within 2%,and it is less correlated with SiO 2.By studying the V/(V +Ni),V/Cr,it is believed that the up-current deposits of Qixia Formation is in the transition environment bewteen rich oxygen and poor oxygen of the slope in the shallow sea,in comparison,the reduction degree of the thin layer for siliceous micro-facies is relatively high.