四川盆地井研—犍为地区寒武系第二统九老洞组古生物化石及其地层划分对比  

FOSSIL ASSEMBLAGES AND STRATIGRAPHIC CORRELATION OF THE JIULAODONG FORMATION(EARLY CAMBRIAN)IN THE JINGYAN—QIANWEI AREA,SICHUAN BASIN

作　　者：潘晓强 董晓霞[2] 代乔坤 骆劲舟 刘紫薇 王同[2] 华洪[1] PAN Xiaoqiang;DONG Xiaoxia;DAI Qiaokun;LUO Jinzhou;LIU Ziwei;WANG Tong;HUA Hong(Shaanxi Key Laboratory of Early Life and Environments,State Key Laboratory of Continental Dynamics,Department of Geology,Northwest University,Xi'an 710069,China;SINOPEC Southwest Oil&Gas Company,Chengdu 610041,China)

机构地区：[1]早期生命与环境陕西省重点实验室,大陆动力学国家重点实验室/西北大学地质学系,西安710069 [2]中国石化西南油气分公司,成都610041

出　　处：《微体古生物学报》2021年第3期241-256,共16页Acta Micropalaeontologica Sinica

基　　金：国家自然科学基金项目(41621003,41890844);国家重点研发项目(Grant No.2017YFC0603101);中石化西南油气公司(勘探开发研究院)项目的资助。

摘　　要：井研—犍为地区麦地坪组—九老洞组是四川盆地寒武系页岩气重要的勘探目的层,但至今区内缺乏比较可靠的古生物化石资料,严重制约着勘探区地层的精确划分与对比。通过对该地区相关资料的收集和金石1井和金页1井岩心样品的采集分析,在本区九老洞组建立了尖头遵义盘虫(Tsunyidiscus acutus)-阎家寨遵义盘虫(Tsun-yidiscus yanjiazhaiensis)和始莱得利基虫(Eoredlichia)-武定虫属(Wutingaspis)两个三叶虫组合,以及梁山虫(Liangshanella)-小遵义虫(Tsunyiella),朵氏昆明虫(Kunmingella douvillei)-卵形川滇虫(Chuandianella ovata(Lee))-简单虫(Mononotella)和峨眉虫(Emeiella)-粗脊昆明虫(Kunmingella(Validocostatella)fusulus)等三个高肌虫组合,为研究区建立了较为详细的化石对比标准;通过典型化石的分析,对比金石1井和金页1井的地层层位,认为金页1井(3403 m以下)和金石1井(3503 m以下)属于深水陆棚相沉积,金页1井(3403m以上)和金石1井(3503 m以上)为海水较浅的陆棚沉积带,推测研究区在寒武纪幸运世早期存在局部断陷,造成了沉积环境的重大变化,反映海平面快速下降及随后原断陷盆地的快速充填。The Maidiping and Jiulaodong formations of the Lower Cambrian are important targets for the shale gas exploration at the Jingyan—Qianwei area,Sichuan Basin.Up to now,lack of fossil information hampers the precise stratigraphic subdivision and correlation in this area.Through collecting and analyzing core samples from the wells of JS1 and JY1,two trilobite assemblages,i.e.Tsunyidiscus acutus-Tsunyidiscus yanjiazhaiensis and Eoredlichia-Wutingaspis assemblages,and three bradoriid assemblages,namely Liangshanella-Tsunyiella,Kunmingella douvillei-Chuandianella ovata(Lee)-Mononotella and Emeiella-Kunmingella(Validocostatella)fusulus assemblages,were established in ascending orders,which in turn,lie solid foundation for a detailed stratigraphic correlation in the Jingyan-Qianwei area,Sichuan Basin.Through the analysis of typical fossils and their stratigraphic distribution,it is considered that JY1(below 3403 m)and JS1(below 3503 m)belong to the deep-water shelf facies deposits,and JY1(above 3403 m)and JS1(above 3503 m)ascribe to the shallow shelf deposit zone.It is speculated that there was a local fault depression in the study area in the incipient of the Lower Cambrian,which caused a major change of the sedimentary environment,reflecting a rapid dropping of sea level and filling of the original fault basin afterwards.

关 键 词：化石组合 地层对比 九老洞组 寒武系第二统 井研—犍为地区 

分 类 号：Q911.2[天文地球—古生物学与地层学] P539[生物学—古生物学]