王家坪下寒武统沉积相研究

Sedimentary facies of Lower Cambrian in Wangjiaping region

施辉 李建明 李惠

Shi Hui Li Jianming Li Hui

油气资源与勘探技术教育部重点实验室, 湖北荆州 434023; 长江大学地球科学学院, 湖北荆州 434023

Key Laboratory of Exploration for Oil and Gas Resource(Ministry of Education), Jingzhou 434023; Geoscience College of Yangtze University, Jingzhou 434023

宜昌莲沱王家坪地区早寒武世沉积了以黑色炭质页岩夹灰岩、细碎屑岩、石灰岩、白云岩等为主的岩性组, 反映了中扬子区岩性四分的特点。根据对野外剖面、显微分析和地层对比等资料的综合分析, 下寒武统主要发育台地、台地边缘和斜坡-盆地三种沉积体系, 并可进一步划分为5种相和10种亚相。早寒武世早期遭受了短暂而快速的海进之后, 依次经历了盆地、陆棚、缓坡、开阔台地、局限台地等沉积环境的缓慢演化, 显示了有规律的海退序列。研究区从水井沱期和石牌期的初期淹没型台地发展到天河板早期的缓坡型台地, 海平面进一步下降, 天河板中期以后镶嵌陆架型台地的格局基本确立。

Black shales interbeded with limestones fine clastic rocks limestones, and dolomites were deposited in Wangjiaping region during the Early Cambrian Period.This region was a shallow sea depositional area,and there are four lithologic types in middle Yangtze area.According to field section,microscopic analysis and coenocorrelation plaform platform edge and slope-basin developed during the Early Cambrian Period which can be further divided into five facies and ten sub-facies.After the rapid transgression in the beginning of the Early Cambrian Period the depositional enviroment evolved regularly and slowly form basin to continental shelf gentle slope open platform and restricted platform indicating a regressive sequence.Mosaic shelf platform has formed basically after the area developed from submerging platform to gentle slope platform.

https://doi.org/10.3969/j.issn.1008-2336.2009.02.005