四川类前陆盆地须家河组层序—岩相古地理特征  

Sequence-based Lithofacies and Paleogeographic Characteristics of Upper Triassic Xujiahe Formation in Sichuan Basin

作　　者：郑荣才[1] 戴朝成[1] 朱如凯[2] 翟文亮[1] 高红灿[1] 耿威[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),成都610059 [2]中国石油勘探开发研究院油气储层重点实验室,北京100083

出　　处：《地质论评》2009年第4期484-495,共12页Geological Review

基　　金：国家重大专项"大型油气田及煤层气开发"(编号2008ZX05000-003-01)的成果

摘　　要：通过对四川盆地的构造格局和盆—山耦合关系分析,确定该盆地属于类前陆盆地,晚三叠世须家河期具备以川中古隆起为中心的,由川西坳陷、川东北坳陷、渝东—川东南坳陷三个盆—山耦合次系统组成的"三坳围一隆"构造—沉积格局。以盆缘地表及盆地内钻井剖面的须家河组和香溪群地层划分、沉积相和层序地层分析、基准面旋回划分及区域等时对比为依据,将须家河组划分为全盆地范围内可追踪对比的2个超长期(SLSC1—SLSC2)和5个长期(LSC1—LSC5)基准面旋回层序。以此为基础,选择各长期旋回层序上升和下降半旋回相域为等时地层单元编制四川盆地层序—岩相古地理图。编图结果表明须家河组各时期岩相古地理面貌、相带展布规律和沉降—沉积中心及其迁移方向,严格受龙门山和米仓山—大巴山两造山带非同步的、但交替发育的逆冲推覆作用与"三坳围一隆"构造—沉积格局控制,盆—山间的耦合关系具有造山带隆升蚀顶与盆地横向生长、沉降、充填的物质循环平衡过程。这一独具特色的构造—沉积格局始终控制着须家河组各超长期、长期旋回层序的沉积充填作用,古地理面貌、生储盖组合特征和围绕川中古隆起为中心的油气成藏规律。Through the analysis of the tectonic framework and Coupling Process between Basin and Mountain,it can be ascertained that the Sichuan Basin is an analogous foreland basin, of which tectonosedimentary framework was composed of three depressions and one uplift, formed by three systems of coupling process between basin and mountain in the Xujiahe epoch of Late Triassic. Based on the analysis of outcrops, drilling sections, sedimentary facies and sequence stratigraphy of the Xujiahe Formation or the Xiangxi Group, combining with the base-level cycle sequence and isochronic correlation technique, the Xujiahe Formation is divided into two super long-term sequence cycles（SLSC1,SLSC2） and five long-term sequence cycles（LSC1-LSC5）, which can be correlated in the whole Sichuan Basin. Choosing the rising and falling base-level phases of each long-term sequence cycles as a unit, the sequence-based lithofacies and paleogeographic maps of the Xujiahe Formation have been mapped. The results indicate that the paleogeography,regulation of sedimentary facies distribution, subsidence--sediment center and migration direction are controlled strictly by nonsynchronous thrusting--napping process of the Longmen Mountains,Micang Mountains--Daba Mountains and so-called＂three depressions and one uplift＂tectonic pattern, which is composed of western Sichuan depression, northeastern Sichuan depression, eastern Chongqing--southwestern Sichuan depression and central Sichuan Palaeo-uplift. Coupling process between basin and mountain possess the features of deroofing in orogenic zone and material cycle between growth, subsidence and filling in a basin. The peculiar tectono-sedimentary pattern entirely control the depositional processes, palaeogeographic features and the source--reservoir--seal combination of the Xujiahe Formation, as well the oil and gas accumulation regularity around the central Sichuan Palaeo-uplift.

关 键 词：四川类前陆盆地 上三叠统须家河组 盆-山耦合 构造-沉积格局 层序-岩相古地理 

分 类 号：P618.13[天文地球—矿床学]