四川盆地东部上三叠统须家河组层序一岩相古地理特征  

Sedimentary sequence and paleogeographic characteristics of the Upper Triassic Xujiahe Formation in eastern Sichuan basin

作　　者：郑荣才[1] 李国辉[2] 常海亮[1] 李世临[3] 王小娟[2] 王昌勇[1] 

机构地区：[1]“油气藏地质及开发工程”国家重点实验室,成都理工大学,四川成都610059 [2]中国石油西南油气田分公司勘探开发研究院,四川成都610051 [3]中国石油西南油气田分公司重庆气矿,重庆400021

出　　处：《中国地质》2015年第4期1024-1036,共13页Geology in China

基　　金：国家科技重大专项“四川盆地岩性油气藏富集规律与目标评价”(2011ZX05001-005)资助

摘　　要：以野外剖面、钻井岩心、测井资料、薄片鉴定和古生物特征分析为基础，结合区域地质特征和前人研究成果，对川东垫江地区须家河组沉积-层序特征进行了较为深入的研究和层序界面及洪泛面的识别，结果表明：须一段属于有障壁海岸沉积体系，须二-须六段地层发育湖泊-辫状河三角洲沉积体系；可将研究区内须家河组划分为于全盆地范围内可追踪对比的、分别相当“须下盆”和“须上盆”的2个构造层序及对应于须一至须六段的6个长期旋回层序（LSCI-LSC6）；以长期旋回层序界面和洪泛面为等时地层对比标志，建立了川中隆起-川东南坳陷等时地层格架；选择各长期旋回层序为等时地层单元编制层序一岩相古地理图，解析须家河组各时期岩相古地理特征及相带展布规律。研究成果对指导川东地区须家河组油气勘探有重要意义。Based on the data of field sections, thin sections and well logging, combined with the characteristics of petrology, palaeontology and previous research results, the authors hold that the 1st member of Xujiahe Formation in Dianjiang area of eastern Sichuan basin was developed in the barrier coast sedimentary system, and the 2nd to 6th members of Xujiahe formation were developed in the lacustrine-braided river delta sedimentary system. Based on the recognition of sequence boundaries and flooding surface, the authors divided the Xujiahe Formation into 3 tectonic sequence cycles （Sup-LSC1--Sup-LSC3）, which represent the ＂remnant bay basin＂, ＂lower Xujiahe basin＂ and ＂upper Xujiahe basin＂ formation periods respectively and can be traced through the whole basin. 6 long-term sequence cycles （LSC1--LSC6） which correspond to the 1st to the 6th members of the Xujiahe Formation respectively were also established. At the same time, using the sequence boundaries of long-term cycle and flooding surface as the marks of isochronous stratigraphic correlation, the authors established the isochronous stratigraphic framework from central Sichuan uplift to southeast Sichuan depression zone. On such a basis, the authors chose each long-term sequence cycle as an isochronous stratigraphic unit, and drew the maps of sequence-based lithofacies and paleogeography of the Xujiahe Formation in the study area. The maps indicate the paleogeography and distribution characteristics of sedimentary facies.

关 键 词：前陆盆地 构造格局 沉积相 层序地层 古地理 上三叠统须家河组 四川盆地东部 

分 类 号：P618.13[天文地球—矿床学] P534.51[天文地球—地质学]