川南地区中二叠统栖霞组岩相古地理特征

Lithofacies and Paleogeographic Characteristics of the Middle Permian Qixia Formation in the Southern Sichuan Basin

以川南地区中二叠统栖霞组为研究对象,结合区内野外露头,钻井、测井资料,根据碳酸盐岩地层学,分析不同岩石类型沉积环境及沉积相,编制研究区栖霞组岩相古地理图。结果表明:川南地区栖霞组主要为碳酸盐岩台地沉积环境,由于川西台缘隆起的阻隔作用,研究区西部发育半局限台地相,向东地势降低,海水循环良好,发育开阔台地相,在研究区东部进一步划分出台内洼地亚相,台内滩亚相主要发育在开阔台地相内,分布在ST1、H17、H23井附近。

Taking the Middle Permian Qixia Formation in southern Sichuan as the research object,combined with field outcrops,drilling and logging data in the area,and based on Carbonate rock Stratigraphy,the sedimentary environment and sedimentary facies of different rock types are analyzed,and the lithofacies paleogeography map of Qixia Formation in the study area is compiled.The results show that the Qixia Formation in southern Sichuan is mainly a Carbonate rock platform sedimentary environment.Due to the barrier effect of the platform edge uplift in western Sichuan,semi restricted platform facies are developed in the west of the study area,the terrain is reduced eastward,the seawater circulation is good,and open platform facies are developed.In the east of the study area,the inner depression subfacies are further divided,and the inner platform beach subfacies are mainly developed in the open platform facies,distributed near well ST1,H17,and H23.