塔里木盆地西南地区晚白垩世中晚期海相性南北分异研究  

The North—South Differentiation on the Marine Feature in the Southwest Tarim Basin during Middle—Late of the Late Cretaceous

作　　者：郭宪璞[1] 丁孝忠[1] 赵子然[1] 李建锋[2] GUO Xianpu;DING Xiaozhong;ZHAO Ziran;LI Jianfeng(Institute of Geology,Chinese Academy of Geological Sciences,Beijing,100037;Institute ofC,eomechanics,Academy of Geological Sciences,Beijing,100086)

机构地区：[1]中国地质科学院地质研究所,北京100037 [2]中国地质科学院地质力学研究所,北京100086

出　　处：《地质论评》2018年第5期1078-1086,共9页Geological Review

基　　金：中国石化集团石油勘探开发研究院项目(编号:G5800-15-ZS-WX027);中国地质调查局项目(编号:DD2016-0345);国家自然科学基金资助项目(编号:41672202)的成果~~

摘　　要：塔里木盆地西南地区早白垩世中期(巴列姆期)至晚白垩世早期(赛诺曼—土伦期)的海相性以东西分异为主导,西强东弱,表现为特提斯海水经西部阿莱依海向东扩展,东部处于海侵末端。笔者最近在该盆地南部的皮山地区钻井地层和阿克彻依剖面发现的有孔虫化石,揭示了晚白垩世中—晚期(赛诺—马斯特里赫特期)海水展布及海相性呈现了南北分异的格局,即南部昆仑山前的海相性强于北部天山前,南强北弱。在原来认为处于海水分布几近末端的皮山地区此时出现了以Dentalina、Dentalinoides、Lagena等钙质微孔壳类型为主的有孔虫化石,代表了有一定深度的正常浅海;在阿克彻依剖面则出现包括Hadbergella、Heterohelix、Guembelitria、Conoglobigerina等4属4种浮游有孔虫在内的以钙质微孔壳类型为主有孔虫化石,表明了正常浅海环境。上述化石属种丰富、保存良好,这些证据的发现为重新认识和揭示塔西南盆地这一时期的海相性、海水展布、海流通道等古地理、古构造格局乃至油气资源评价均提供了新材料。Objectives： The Mesozoic—Cenozoic transgression of the Southwest Tarim Basin has conventionally been thought that the sea water came from western Alay region and the marine feature of the strata was gradually getting weak from west to east.Recently,on the basis of feraminifera fossils,authors have been found that the direction of the Middle—Late of Late Cretaceous transgression and marine feature in this basin once changed.Studying on this change is of great significance to reconstruct tectonic paleo-geography and paleo-environment for this basin.Methods： In the South Southwest Tarim Basin,authors have firstly found the Middle—Late Late of Cretaceous feraminifera fossils in two localities.The first locality is the Arcchey section where exist 18 genera and 26 species feraminifera fossils,in which the planktonic type and trochspiral type occupy 15% and 74% of the total amount,respectively.The second site is the drilling core from 6903.93 to 7079.81 meters of well depth in the New 2 well at northern Pishan County,where preserve 12 genera and 39 species benthic feraminifera fossils in which the serial type and lagene type occupy 45% and 50% of the total amount,respectively.According to paleo-ecological analysis for feraminifera fossils as mentioned above,the paleo-environment represent normal shallow sea with deeper water.Nevertheless,the feraminifera fossils are very poor or have not been observed,representing upper intertidal zone or lagoon in the North Southwestern Tarim Basin.Results： The occurrence of feraminifera fossils shows that the Senonian—Maastrichtian normal shallow sea was distributed on leading edge area of the Kunlun Mountains of the South Southwest Tarim Basin.The marine feature of the south is strongerly demonstrated than the north,and direction of transgression once changed.Conclusions： The marine feature of the Senonian—Maastrichtian strata in the south of this basin,i.e.,the Kumlun Mountains front region,is stronger than the north,i.e.,the Tianshan Mountains front region.Thus,th

关 键 词：海相性 南北分异 赛诺—马斯特里赫特期 有孔虫 塔西南盆地 

分 类 号：P534.53[天文地球—古生物学与地层学]