塔中-塔北志留系沉积层序的不对称结构及其构造意义  

Differential depositional architecture of Silurian sequences and its tectonic significance in Tazhong and Tabei areas of Tarim Basin

作　　者：刘景彦[1] 林畅松[1] 李思田[1] 司宝玲[1] 黄振[1] 李换浦[1] 徐应才[1] 苏真真[1] 

机构地区：[1]中国地质大学(北京),教育部海相储层演化与油气富集机理重点实验室,北京100083

出　　处：《岩石学报》2011年第1期297-309,共13页Acta Petrologica Sinica

基　　金：中石化海相前瞻性项目(YPH08114);国家重点基础发展规划(973)项目(2006CB202302,2011CB201103);中央高校基本科研业务费专项资金(2010ZD07)联合资助

摘　　要：志留系沉积期塔里木为一地势相对平坦、水体较浅的陆表海盆地,总体充填一套碎屑海岸和三角洲体系,从下至上可划分出5个三级层序。塔中和塔北志留系沉积层序表现出明显的不对称结构,塔北地区柯坪塔格组三级层序SQ-Skp1、SQ-Skp2和SQ-Skp3沉积较完整,发育潮坪、浅海陆棚、滨岸-三角洲体系;而塔中地区缺失SQ-Skp1和SQ-Skp2层序,SQ-Skp3以潮坪体系为主,局部发育小型三角洲。与此相对,塔中地区塔塔埃尔塔格组层序SQ-Stt沉积完整,而塔北地区缺失SQ-Stt水进体系域红泥岩段。塔中和塔北志留系沉积层序的不对称结构反映了塔中和塔北构造隆升的差异和演化,奥陶末构造运动对塔中影响较大,造成塔中隆起的隆升并一直处于水上隆起,直到柯坪塔格组上段SQ-Skp3层序沉积期才淹没充填,随后持续沉降,形成了完整的塔塔埃尔塔格组层序SQ-Stt;奥陶末构造运动对塔北影响较小,西部英买力地区局部隆升,而东部持续沉降,直到柯坪塔格组沉积之后塔北东部出现较大规模隆升,形成明显的上超不整合,并造成塔塔埃尔塔格组层序SQ-Stt水进体系域红泥岩段缺失。塔中和塔北构造演化控制了盆地的沉积层序和储盖组合发育,塔中缺失下储盖组合,而塔北缺失上储盖组合,对志留系圈闭形成和油气保存具有重要的影响。During the Silurian,there was a relative flat and shallow marine basin of Tarim Basin,filling with clastic shoreline debris and delta system,which can been classified into 5 3th order sequences from bottom to top.The depositional sequence of Silurian in Tazhong and Tabei areas shows an obvious differential architecture,in which the 3th order sequeces of Kepingtage Formation （SQ-Skp1,SQ-Skp2 and SQ-Skp3） developed well in Tabei area,filling with tidal flat,shallow marine mudstone,shoreline and delta systems.While in Tazhong area,the sequence SQ-Skp1 and SQ-Skp2 didn’t develop,and SQ-Skp3 filled with tidal flat system.Contrasted with that,the 3th order sequence of Tataertage Formation （SQ-Stt） developed well in Tazhong area.While in Tabei area,the transgressive tract of SQ-Stt lost and lack of the red mudstone Member of Tataertage Formation.The differential architecture of Silurian depositional sequence reflected the tectonic uplift and evolution difference between Tazhong and Tabei areas.The tectonic movement at the end of Ordovician made greater influence on Tazhong area than that on Tabei area.The strongly compression caused Tazhong uplifting and remaining above sea level,which hasn’t been deposit covered until SQ-Skp3 developing period.With the following subsidence,there formed entire sequence （SQ-Stt） of Tataertage Formation.In Tabei area,only western Yingmaili was uplifted and the eastern keep continuing subsidence.There expressed large scale uplifting in the eastern of Tabei area after Kepingtage Formation deposited,formed obvious onlap unconformity and leaded to the transgressive tract red mudstone of SQ-Stt lost.The tectonic evolution of Tazhong and Tabei areas controlled the development of sedimentary sequence and reservoir-seal combination.There is lack of the lower reservoir-seal combination in Tazhong area.While it is lack of the upper reservoir-seal combination in Tabei,which has caused great influence on the trap forming and oil/gas reserve.

关 键 词：沉积层序的不对称结构 塔中-塔北 志留系 构造活动 储盖组合 

分 类 号：P539.2[天文地球—古生物学与地层学]