古蔺石鹅地区夜郎组沉积相浅析

The analysis of Yelang Formation sedimentary characteristics in gulin county,Sichuan province

通过对三叠系下统夜郎组的岩性、岩相、岩石结构构造、古生物等特征的综合资料,以及区域地质矿产调查及实测地层剖面成果综合研究认为,夜郎组属台地边缘沉积相,划分为潮坪-开阔台地-潮坪亚相,沙堡湾段为泥坪位于潮上带,水位较高,向上逐渐变深,为泥灰坪,黄村坝段为台地相,其中鲕粒灰岩为台缘边滩,沙堡湾段至黄村坝段海水变深,代表一期海侵,九级滩段为潮坪砂泥坪沉积,海水变浅,代表一期海退。该认识希望为该地区的地质勘查提供一定的帮助。

Based on the characteristic of rock property,lithofacies,rock structure,and ancient fossil,analysed from data of regional geological mineral survey and stratigraphic section,we think Yelang Formation belongs to the platform margin,divided into3sedimentary facies:tidal flat,open platform,tidal flat.It was mudflat in supratidal zone in the first period,then water level went high,and gradually became deeper,deposited marl.It was platform facies in the second period,deposited oolitic limestone,it belonged to platform-margin beach facies,sea level became deeper,on behalf of the transgression of sea;deposited sand mudflat in the third period,and sea level became shallower,on behalf of the regression of sea.This research is in combination with macroscopic and microcosmic geological data,discusses rock association and sedimentary environment,we hope it provides theoretical foundation of geological exploration.