安徽淮南下寒武统沉积环境以及碳酸盐岩微相分析

华北地台南缘安徽淮南老鹰山剖面下寒武统猴家山组和馒头组的沉积环境和碳酸盐岩微相指示了３期地区性海进沉积旋回序列。假整合于前寒武系凤台组冰积砾岩层之上的猴家山组蒸发相白云岩和馒头组下段的深褐色页岩、钙质页岩和深灰色、灰色中厚层至薄层灰岩构成第１个海进序列；馒头组中段的页岩和薄层灰岩及馒头组上部的深褐色页岩构成第２个海进序列；第３次海进以近馒头组顶部的页岩出现为标志，至老鹰山组下段局部地区的剥蚀面作为中下寒武统的界限和第二次海退的终结。

Environments and Carbonate Microfacies of Lower Cambrian in Huainan,Anhui

Three periods of local transgression and regression sequences occured on the southern margine of North China Platform at the end of Early Cambrian Longwangmiao Stage.The analysis of the sedimentary environments and carbonate microfacies in the Lao yingshan section of Huainan,Anhui Province,indicates these cycles.The base of Houjia shan Formation,which is paracomformable with the Late Precambrian Fengtai Formation glacial debries,beginning with the phosphorits shows that the first transgression formed in shallow water evaporate between supratidal and intertidal zones. Owing to the advancing transgression procession, the lower part of the Mantou Formation consists of relatively deep water shales and limestones.The secondary transgression sequence constructed the shales and limestones in the middle part of the Mantou Formation.The deep water shales at the top part of the Mantou Formation suggests the third transgression, which is the deepest of three transgressions, and the shallow water limestones and a erosion surface in the lower part of the Laoyingshan Formation shows the closing of regression by the end of the Longwangmiao Stage.