早—中侏罗世塔西南山前地区沉积过程探讨  

On the Depositional Process in the Southwest Tarim Basin During the Early-middle Jurassic

作　　者：何翔 李群[2] HE Xiang;LI Qun(School of Earth Sciences,China University of Geosciences,Wuhan 430074,China;School of Geosciences and Info-Physics,Central South University,Changsha 410083,China)

机构地区：[1]中国地质大学地球科学学院,湖北武汉430074 [2]中南大学地球科学与信息物理学院,湖南长沙410083

出　　处：《湖南科技大学学报（自然科学版）》2022年第3期20-26,共7页Journal of Hunan University of Science And Technology：Natural Science Edition

基　　金：中国地质调查局项目资助(DD20160060)。

摘　　要：为探讨塔西南山前地区在早—中侏罗世的沉积过程,实测了区内奥依塔克剖面,结合前人的研究成果,综合分析中—下侏罗统沉积序列、沉积物特征、沉积时区域构造环境和古地形特征、沉积相展布等信息.研究表明:早—中侏罗世期间,塔西南山前地区的古地形,不仅在垂直造山带方向上存在数排隆起,而且在平行造山带方向上也是系列隆起,沉积物受古地形特征的影响,在这2个方向上扩展,侏罗纪前形成的系列断陷盆地在此期间被”填平补齐”.早侏罗世早期,燕山I幕的活动强度相对较弱,沉积局限于靠近断裂的区域;早侏罗世后期,燕山II幕的活动强度相对强,沉积物将小型凹地(断陷盆地)充填,并开始相互连通相邻凹地;中侏罗世,延续了之前的构造环境,各相邻凹地大规模连通.早—中侏罗世,研究区经历了沉积范围由局限到广泛、沉积物粒度由粗到细、沉积凹地由独立到相通的沉积过程.In order to discuss the depositional process of the early-middle Jurassic in the front area of the Kunlun Mountain in the west of the Tarim Basin, based on the actual measurement of the oitak geological section in this area, and combined with the previous research results, this paper comprehensively analyzes the depositional sequence of the middle-lower Jurassic, sediment characteristics, the regional structure and paleotopography characteristics at the time of deposition, and the distribution of sedimentary facies. The results shows that during the early-middle Jurassic, there were not only several rows of uplifts in the direction of vertical orogenic belt, but also high and low undulations in the direction of parallel orogenic belt. The sediments were affected by the characteristics of paleotopography, and extended in these two directions. The series of fault basins formed before the Jurassic were “filled up” during this period. In the early stage of early Jurassic, the activity intensity of Yanshan I episode was relatively weak, and the deposition in this period was limited to the area near the fault. In the later period of early Jurassic, the activity intensity of Yanshan II episode was relatively strong, the sediments filled small depressions(fault basin) and began to connect adjacent depressions. In the middle Jurassic, the previous tectonic environment continued, and the adjacent depressions were connected in large scale. In the early-middle Jurassic, the study area experienced a sedimentary process from limited to extensive, from coarse to fine, and from independent to interlinked.

关 键 词：早—中侏罗世 沉积过程 塔西南地区 

分 类 号：P531[天文地球—古生物学与地层学]