重庆万盛中二叠统碳酸盐岩微相研究

重庆市万盛区中二叠统碳酸盐岩分布广泛，露头发育良好，发育有10种微相类型，即灰泥石灰岩、筵粒泥灰岩、球粒生物碎屑粒泥灰岩、生物碎屑内碎屑泥粒灰岩、荷叶藻泥粒灰岩、鲕粒内碎屑泥粒岩/颗粒岩、小有孔虫泥粒灰岩、生物碎屑泥粒灰岩、绿藻颗粒灰岩和生物碎屑颗粒灰岩。综合分析表明，研究区中二叠统形成于滨岸、局限台地和开阔台地环境，据此建立了沉积相模式。

The Middle Permian carbonate rock microfacies in the Wansheng district, Chongqing

The samples of the Middle Permian carbonate rock outcrops examined in this paper were mainly (collected) from the Wansheng district, Chongqing. The Qixia and Maokou Formations both of which are (assigned) to the Middle Permian in age, consist of marine siliciclastic and carbonate rocks. The carbonate deposits account for about 80 per cent of the sedimentary rocks in the study area. According to textural-genetic classification, grain types, sedimentary structures and fossils, the carbonate rocks herem can be recognized as ten types of microfacies, including lime mudstone, fusulinid wackestone, pelleted bioclastic wackestone, bioclastic-intraclastic packstone, algal-mat (patellate) packstone, oolitic intraclastic packstone/grainstone, foraminiferal packstone, bioclastic packstone, green algal grainstone, and bioclastic grainstone. It is inferred from the microfacies division and microenvironmental analysis that the Middle Permian strata were deposited in the littoral, restricted platform and open platform environments. A facies model has been constructed for the above-mentioned depositional environments.