川东南地区下志留统石牛栏组岩相古地理及生物礁滩发育特征

基于露头、岩心、钻井及测井等资料，对川东南地区下志留统石牛栏组岩相古地理及生物礁滩发育特征进行了详尽分析。结果表明：(1)石牛栏组可划分为2个三级层序，每个三级层序下部发育海侵体系域，上部发育高位体系域；(2)石牛栏组可划分为三角洲、局限台地、台地边缘浅滩、台地边缘生物礁、台地边缘缓坡和陆棚相沉积；在层序格架内，编制岩相古地理图，台地边缘浅滩和生物礁相主要发育在层序SQ1高位体系域和层序SQ2，岩性主要为生物礁灰岩和生屑灰岩；(3)研究区主要发育3期台地边缘生物礁、滩，第一期为层序SQ1高位体系域，第二期为层序SQ2海侵体系域中下部，第三期为层序SQ2高位体系域中上部，其中第二期发育规模最大；(4)台地边缘生物礁滩发育主要受海平面升降、古隆起和陆源碎屑物质输入共同控制，海平面升降控制生物礁滩纵向上发育厚度及向台缘迁移。黔中古隆起抬升使海岸线向北迁移，从而迫使生物向北迁移，雪峰古隆起提供的陆源碎屑物质造成生物逃亡或死亡，一定程度上限制了生物礁滩发育。

Lithofacies palaeogeography and development characteristics of reef shoal in Lower Silurian Shiniulan Formation in southeastern Sichuan Basin

Based on outcrop， core， drilling and logging data， this paper makes a detailed analysis on the lithofacies palaeogeography and biological reef shoal development characteristics of the Lower Silurian Shiniulan Formation in southeastern Sichuan Basin. The results show that： （1） The Shiniulan Formation can be divided into two third-order sequences， with transgressive system tracts developed in the lower part of each sequence and high-order system tracts developed in the upper part. （2） Shiniulan Formation can be divided into delta， limited platform， platform edge shoal， platform edge reef， platform edge ramp and shelf facies. In the sequence framework， the lithofacies palaeogeography map is compiled. The platform edge shoals and reef facies are mainly developed in the high system tract of sequences SQ1 and SQ2， and the lithology is mainly reef limestone and bioclastic limestone. （3） Three stages of platform margin reefs and shoals were mainly developed. The first stage was the high system tract of sequence SQ1， the second stage was the lower part of transgressive system tract of sequence SQ2， and the third stage was the upper part of transgressive system tract of sequence SQ2. The second stage was the largest. （4） The development of the reef shoal at the edge of the platform is mainly controlled by the sea level rise and fall and the input of terrigenous clastic materials， and the sea level rise and fall controls the longitudinal development thickness and migration to the edge of the platform. The uplift of the paleo-uplift in central Guizhou makes the coastline migrate northward， which forces the organisms to migrate northward. The terrigenous clastic material provided by the Xuefeng paleo-uplift causes the escape or death of organisms， which limits the development of biological reefs to some extent.