中上扬子地区晚二叠世长兴期岩相古地理  

Lithofacies palaeogeography of the Late Permian Changxing Age in Middle and Upper Yangtze Region

作　　者：何幼斌[1] 罗进雄[1] 

机构地区：[1]长江大学地球科学学院,湖北荆州434023

出　　处：《古地理学报》2010年第5期497-514,共18页Journal of Palaeogeography：Chinese Edition

基　　金：中国石油化工股份有限公司海相油气勘探前瞻性项目"南方二叠系定量岩相古地理研究及油气预测"(编号:YPH08019)资助

摘　　要：中上扬子地区上二叠统长兴阶岩石类型主要为碳酸盐岩,其次为碎屑岩和硅岩,还有少量煤和火山碎屑岩;其岩相可归纳为碎屑岩型、碎屑岩—石灰岩型、石灰岩型、石灰岩—硅岩型、硅岩—碎屑岩型等5种类型;其生物化石具4个基本生态类型,可划分为5种化石组合。以沉积岩石学理论为指导,以单因素分析多因素综合作图法为方法论,选取了厚度、海相岩含量、浅水碳酸盐岩含量、具灰泥基质的生屑含量、具亮晶胶结的生屑含量、生物礁的分布、薄层硅岩含量和深水沉积岩含量等单因素,对中上扬子地区晚二叠世长兴期岩相古地理进行研究,编制出了单因素图件8幅,岩相古地理图1幅。研究表明,长兴期岩相古地理格局规律明显,自西向东依次出现剥蚀区、冲积平原、碎屑岩台地、碳酸盐岩台地、斜坡与盆地,其中碳酸盐岩台地中可以划分出低能生物滩、高能生物滩和生物礁等次一级的古地理单元;沉积环境对烃源岩的发育具有明显的控制作用,研究区大隆组优质烃源岩发育;长兴阶储集层以礁相储集层为主,环广元—梁平盆地的台地边缘地区是长兴组潜伏礁型油气藏的最有利勘探区域。The Upper Permian Changxing Stage is mainly composed of carbonate rocks,while clastic rocks and siliceous rocks are also developed,with small quantity of coal and pyroclastic rocks.Its lithofacies mainly includes five types： Clastic rock type,clastic rock-limestone type,limestone type,limestone-siliceous rock type,and siliceous rock-clastic rock type.Four fundamental ecological types and five fossil assemblages were recognized in the Changxing Stage.Based on theories of sedimentary rocks,according to the single factor analysis and multifactor comprehensive mapping method,the lithofacies palaeogeography of the Late Permian Changxing Age in Middle and Upper Yangtze Region was studied and mapped. The single factors include thickness,content of marine rocks,content of shallow water carbonate rocks,content of biograins with limemud matrix,content of biograins with sparry cement,distribution of reefs,content of thin bedded siliceous rocks and content of deep water sedimentary rocks.Totally eight single factor maps and one lithofacies palaeogeography map of the Changxing Age were compiled. The results show that the lithofacies palaeogeography framework of the Changxing Age has obvious regulation.From west to east, there were erosional area,fluvial plain,clastic platform,carbonate platform,slope and basin,and on the carbonate platform,the low-energy organic banks,high-energy organic banks and reefs were developed.The sedimentary environments have an obvious control on the development of the source rocks,and the excellent source rocks were developed in the Dalong Formation.The reservoir of the Changxing Stage should be dominated by the reef,and the platform marginal surrounding the Guangyuan-Liangping Basin rim area is the most favorable exploration area of the reef petroleum reservoirs of the Changxing Formation.

关 键 词：中上扬子地区 二叠纪 长兴期 岩相古地理 单因素 

分 类 号：P531[天文地球—古生物学与地层学]