准噶尔盆地南缘侏罗系重矿物特征及其物源指示意义  

New insights into multiple provenances evolution of the Jurassic from heavy minerals characteristics in southern Junggar Basin,NW China

作　　者：周天琪[1,2] 吴朝东[1,2] 袁波 史忠奎 王家林 朱文 周彦希 姜晰 赵进雍 王军[6] 马健[1,2] ZHOU Tianqi;WU Chaodong;YUAN Bo;SHI Zhongkui;WANG Jialin;ZHU Wen;ZHOU Yanxi;JIANG Xi;ZHAO Jinyong;WANG Jun;MA Jian(Key Laboratory of Orogenic Belts and Crustal Evolution,MOE,Peking University,Beijing 100871,China;Institute of Oil & Gas,Peking University,Beijing 100871,China;Geophysics Department in Exploration and Development Institution of Xinjiang Oilfield Company,Urumqi 834000,China;Institute of Remote Sensing and Geographical Information System,School of Earth and Space Sciences,Peking University,Beijing 100871,China;Petroleum Exploration and Production Research Institute,Sinopec,Beijing 100083,China;Department of Xinjiang Exploration Project Management,Sinopec Shengli Oilfield Company,Dongying 257000,China)

机构地区：[1]北京大学造山带与地壳演化教育部重点实验室,北京100871 [2]北京大学石油与天然气研究中心,北京100871 [3]新疆油田公司勘探开发研究院地球物理研究所,新疆乌鲁木齐830000 [4]北京大学地球与空间科学学院遥感与地理信息系统研究所,北京100871 [5]中国石化石油勘探开发研究院,北京100083 [6]中国石化胜利油田分公司新疆勘探项目管理部,山东东营257000

出　　处：《石油勘探与开发》2019年第1期65-78,共14页Petroleum Exploration and Development

基　　金：国家科技重大专项(2011ZX05009-001)

摘　　要：应用随机森林分类法对准噶尔盆地南缘侏罗系2 418个样品的重矿物组合进行分类,确定了准噶尔盆地南缘侏罗系具有同源特征的重矿物组合分布,在此基础上结合稳定重矿物指数(ZTR)、沉积环境特征、古流向、U-Pb锆石年龄以及微量元素分析,探究准噶尔盆地南缘侏罗系不同构造单元的物源体系演化特征。研究区侏罗系主要存在北天山、中天山、扎伊尔山、博格达山以及卡拉麦里山5个物源区,其中早侏罗世以北天山—中天山、卡拉麦里山以及扎伊尔山为主物源区,中侏罗世博格达山开始隆升并提供物源。准噶尔盆地南缘侏罗系主要存在西部、中部及东部3个汇水区。准噶尔盆地南缘西部早侏罗世物源主要来自北天山及扎伊尔山,而中—晚侏罗世均以扎伊尔山为主物源区。准噶尔盆地南缘中部早侏罗世主物源区逐渐由北天山后退至中天山,西山窑组主物源区又重新从中天山回至北天山,头屯河组以及齐古组沉积时期均以北天山为主物源区。准噶尔盆地南缘东部早侏罗世—西山窑组沉积时期主要物源来自卡拉麦里山以及中天山,少量来自北天山;西山窑组沉积时期博格达山开始隆升并提供少量物源,头屯河组沉积时期博格达山隆升为主物源区,少量物源来自中天山;随博格达山进一步隆升,齐古组沉积时期中天山物源供给受阻,物源主要来自博格达山以及北天山。The method of random forest was used to classify the heavy mineral assemblages of 2 418 Jurassic samples in the southern Junggar Basin,and determine the distribution of the heavy mineral assemblages from the same provenance systems.Based on the analysis of heavy minerals assemblages,ZTR index,sedimentary characteristics,U-Pb zircon ages,whole-rock geochemical and paleocurrent analysis,the study reveals that five important provenances were providing sediments to the southern Junggar Basin in the Jurassic period:The North Tianshan(NTS),Central Tianshan(CTS),Bogda Mountains,Zhayier Mountains and Kalamaili Mountains.During the Early Jurassic,NTS-CTS,Kalamaili Mountains and Zhayier Mountains are primary provenances,Bogda Mountains started to uplift and supply clastic materials in the Middle Jurassic.There are three catchment areas in the Jurassic of southern Junggar Basin:the western part,the central part and the eastern part.In the western part,the provenance of the Early Jurassic was mainly from NTS blocks and Zhayier Mountains,and the sediments were mainly derived from the Zhayier Mountains during the Middle-Late Jurassic.In the central part,the main provenance of the Early Jurassic switched from NTS to CTS.In the Xishanyao Formation,the main provenance area went back to NTS again.The NTS was the main provenance during the sedimentary periods of Toutunhe Formation and Qigu Formation.In the eastern part,the contribution of CTS and Kalamaili Mountains were considered as major provenances in the Early Jurassic?Xishanyao Formation,small proportion of sediments were from NTS.The Bogda mountains were uplifted and started to provide sediments to the Junggar Basin in the sedimentary period of Xishanyao Formation,and became the major source during the Toutunhe Formation period,with small amount of sediments from CTS.The provenance from CTS was hindered during the sedimentary period of Qigu Formation owing to the uplifting of the Bogda mountains,and the sediments were mainly from the Bogda mountains and NTS.

关 键 词：准噶尔盆地南缘 侏罗系 源-汇系统 物源 重矿物组合 层次聚类-随机森林分类 

分 类 号：TE121.1[石油与天然气工程—油气勘探]