扬子板块北缘孤峰组地层划分及空间分布特征

STRATIGRAPHIC DIVISION AND SPATIAL DISTRIBUTION OF THE MIDDLE PERMIAN KUHFENG FORMATION IN THE NORTHREN YANGTZE BLOCK

扬子地台北缘中二叠统孤峰组主要由黑色硅—泥质岩石组成，化石丰富，成藏条件较好，是我国页岩气勘探开发有利区带之一。通过对中二叠统孤峰组地层进行放射虫化石带和岩性地层对比，认为孤峰组由下至上可划分为3～4段：硅质泥岩段、泥质硅质岩段、硅质—钙质泥岩段和炭质泥岩段，部分地区缺失炭质泥岩段。通过对野外露头剖面实测和钻孔岩芯原始资料以及前人研究成果的收集，依照60条剖面和钻井资料探讨扬子北缘中二叠统孤峰组页岩的分布特征，并按岩性特征对孤峰组页岩空间分布做了进一步细分，绘制出该区孤峰组各段的岩性等厚图。为该层系页岩气资源评价和勘探开发打下了良好基础。

The Middle Permian Kuhfeng Formation in the northern margin of the Yangtze Plate is characterized by fossiliferous black shale and cherts, which are favorable targets for shale gas exploration and development. This paper discusses the lithostratigraphy and biostratigraphy of the Kuhfeng Formation, which can be divided into the four members including, in ascending order, a siliceous mudstone member, an argillaceous siliceous rock member, a siliceous-calcareous mudstone member, and a carbonaceous mud- stone member. The carbonaceous mudstone member can be missing at some sections. Based on stratigraphic data from 60 outcrop sections and drill cores, the spatial distribution of each member and its thickness are mapped. The results form a solid foundation for the evaluation, exploration, and development of shale gas resources from the Kuhfeng Formation in the northern margin of the Yangtze Plate.