沧水铺群的演替及其岩石地层学问题——论湖南新元古界底部岩石地层序列

摘要

A unique lithostratigraphic unit occurring discordantly between the Banxi and Lengjiaxi Groups at Yiyang County,Hunan Province,China,was first discovered in 1977 by Pan Chuanchu et rnal.This unit was named Cangshuipu Group,and its lower conglomerate Lingjiawan formation,the upper pyroclastic rocks Yinzhuba Formation. rn　　In 1988,Luo Haiyan proposed that the Baolinchong Formation,attributed to the Lengjiaxi Group,must be denominated in order to replace the Cangshuipu Group because he considered that the bed successions of the Cangshuipu Group was upended. rn　　In 1995,Tang Xiaoshan renamed the conglomerate unit Hengluchong Formation of the Banxi Group instead of the Lingjiawan Formation of the Cangshuipu Group. rn　　Dealing with the conglomerate and the pyroclastic rocks unit at Cangshuipu,Hunan,《 The Lithostratigraphy of Hunan Province》 (1997) not only did not introduce the evolution of denomination of the strata and did not wonder if the bed successions of the Baolinchong Formation is right or upset,but also did not mention any information about the Cangshuipu Group. rn　　As a result ,there occur a few principle problems on denominating,dividing and correlating of Hunan Proterozoic strata on lithostratigraphy. rn　　The author demonstrats the bed successions of the Cangshuipu Group is right,but the bed successions of Baolinchong Formation is upset with data on the conglomerate component, metamorphic feature,section geology,regional geology and drilling holes as well as experts examination from the Cangshuipu region.%本文通过介绍沧水铺群创建和演绎的过程以及因其被演替后所面临的岩石地层学问题，认为《湖南省岩石地层》（ 1997）中，新元古界底部——冷家溪群与板溪群马底绎组之间——的宝林冲组火山岩→横路冲组砾岩序列是主观虚拟的，沧水铺群林家湾组砾岩→银珠坝组火山岩序列是客观存在不容置疑替代的，并从砾石成分、变质特征、地质剖面、区域分布、专家检验以及钻探地质工程难验证等方面予以论证。