安徽巢湖地区石炭纪-早二叠世碳酸盐岩微相与沉积环境

Carboniferous-Early Permian carbonate microfacies and sedimentary environments in the Chaohu region, Anhui

关键词:  安徽  碳酸盐岩  沉积微相  沉积环境  石炭纪  早二叠世

Key words:  Anhui  carbonate rock  sedimentary microfacies  sedimentary environment  Carboniferous  Early Permian

摘要:

安徽巢湖凤凰山剖面出露石炭系金陵组(C₁j)、和州组(C₁h)、黄龙组(C₂h)、船山组(C₂c)以及下二叠统栖霞组下部臭灰岩段(P₁q)等5个含碳酸盐岩地层。本文在野外剖面实测的基础上,对这些碳酸盐岩进行了岩相与微相分析。通过对碳酸盐岩显微薄片的观察分析,共识别出14个微相,分属于干旱近海岸蒸发台地(潮坪)、局限海台地、开阔台地内部浅滩、开阔海台地等4种沉积环境。本文研究结果表明,石炭纪-早二叠世期间,巢湖地区主要为浅海碳酸盐台地环境,期间发生了3次比较大规模的海侵-海退旋回,并间隔有若干次小规模的海平面升降。

Abstract:

In the light of field investigation in recent years, the present paper gives a detailed description of the carbonate strata in the Fenghuanshan section in Chaohu, Anhui, including the Carboniferous Jinling Formation (C₁j), Hezhou Formation (C₁h), Huanglong Formation (C₂h), Chuanshan (C₂c) and stinkstone member in the lowermost part of the Lower Permian Qixia Formation (P₁q). Fourteen sedimentary microfacies have been distinguished for the carbonate rocks on the basis of thin-section examination of the carbonate rocks, and are involved into the following sedimentary environments:arid coastal evaporate platform (tidal flat), restricted carbonate platform, intraplatformal shoal and open carbonate platform. The results of research in this study show that the Chaohu region in Anhui was once occupied by the shallow marine carbonate platform during the Carboniferous-Early Permian, and went through three large-scale transgression-regression cycles with a number of small-scale sea-level fluctuations.