【作者】 冉书明；

【导师】 王根厚；

【作者基本信息】 中国地质大学（北京） ， 构造地质学， 2003， 硕士

【摘要】 柴达木盆地北缘赛什腾—锡铁山左行斜冲断裂研究得到国家重点基金研究发展规划项目(G1998040800)和鱼卡、绿梁山幅1：5万区域地质调查项目的资助。赛什腾——锡铁山左行斜冲断裂带呈北西—南东延伸，断裂带内部发育断层泥、断层角砾及断层带劈理等，断层上盘为赛什腾——锡铁山组成的推覆体，推覆体成右行斜列展布，下盘主要地层组成为新第三纪油沙山组。本文在对赛什腾——锡铁山斜冲断裂详细地段构造解析的基础上，结合盆地的沉积特征、地球物理资料等对该斜冲断裂的几何学、运动学及形成时代进行了研究，论文着重探讨了赛什腾——锡铁山斜冲断裂的地质意义。 (1)对柴达木盆地北缘的赛什腾——锡铁山一带出露的地层进行了较为系统的划分，厘定了古元古代达肯大坂岩群、奥陶——志留纪滩间山(岩)群、泥盆纪上泥盆统埃姆尼克群、石炭——二叠纪中吾农山群果可山组。将本区的地层划分为两个构造层：既变质岩系构成的基底构造层；中生代、新生代的沉积岩系构成的盖层构造层。 (2)对柴达木盆地北缘的赛什腾—锡铁山左行斜冲推覆构造的几何特征进行了系统研究，根据推覆体展布以及与凹陷关系将其分为三段，即呈斜列式展布赛什腾、绿梁山和锡铁山左行斜冲断裂。 (3)根据断裂断裂带的宏观特征、断层带劈理特征、断裂带附近的牵引褶皱和断层下盘的平面反“S”型褶皱以及断层上盘剖面正花状构造和平面左行小型平移断层，认为赛什腾-锡铁山断裂带运动学主要表现为剖面上的逆冲、平面上的左行走滑特点，并且走滑量具有自西向东增大之势。但总体以逆冲为主。因此，将其称为左行斜冲断裂构造。 (4)通过对赛什腾——锡铁山南侧盆地内部构造展布、盆地内地层厚度变化以及地震地质资料分析，探讨了赛什腾——锡铁山斜冲断裂作用在盆地内的响应。认为逆冲推覆构造的展布与盆地内的褶皱构造、断裂构造的展布具有一致性。逆冲推覆构造呈斜列式形展布与盆地内的也呈斜列式反“S”形展布的构造具有密切关系，都属于断裂左行斜冲的产物。 (5)根据地震质料、沉积特征、地层的沉积接触关系、断裂切割地层关系以及与断裂相关的褶皱卷入地层的研究，认为柴达木盆地北缘的赛什腾——锡铁山逆冲推覆构造形成于中侏罗世，而左行逆冲断裂带定型于新第三纪上新世末。推覆构造的形成，导致柴达木地块下沉，推覆体持续逆冲盆地持续沉积，沉积中心也变更。 (6)论文探讨了赛什腾——锡铁山斜向逆冲推覆构造的地质意义，认为赛什腾-锡铁山断裂斜冲作用是印度板块与欧亚板块碰撞、会聚的远程效应的结果，该认识对于研究柴北缘区域构造格局、盆山关系以及更大尺度的断裂带或造山带的斜向逆冲作用具有理论意义，对柴达木北缘的油气预测、推覆体金属矿床的分布、形成具有指导意义。通过该断裂带的研究，有利于进一步探讨青藏高原的隆升机制。更多还原

【Abstract】 Based on the national key project for basic research on Tibetan plateau (G1998040800) and the 1:50000 regional geological survey project of Yuka and Liuliangsan area ,a Neogene Sertenshan-Xitieshan Obligue -Trusting Fault of (SXOTF) is stuied in the Northern Qaidam Basin. SXOTF is recognized in the Northern Qaidam based on the analysis of structures of area.This oblique trusting fault zone with northwestern-southeastern trending consists of Fault gouge,fault breccia and fault cleavage. Fault hanging wall consists of Sertengshan-Xitieshan napple, which is distribution in dextral en echelon. Fault footwall consists of Youcangshan Formation in Neogene. This paper emphasize the research of geometry, kinematics, age of formation of oblique-thrustin. It is discussed that geological significance of obligue -trusting.(1) This paper classified the strata of Sertengshan-Xitieshan in northern Qaidam basin into Daken-dabanyan group in Lower Proterozoic, Tanjianshan group in Ordovician-Silurian period, Aimunike group in Upper Devonian period and Guokesan formation of Zhongwu-nunsan group in Permo-Carboniferous. The strata of the region are divided into two structural layers: the basement rock consisting of metamorphic rock and cover layer of Mesozoic and Neozoic sedimentary rock..(2) The geometry of left oblique-thrust fault zone of Sertengshan-Xitieshan in northern Qaidam basin was studied systemically. According to the spread of nappe and relation between the nappe and depression, Oblique-thrust fault zone was divided into three parts in this paper: Sertengshan,Lvliangshan and Xitieshan.(3) According to macroscopic characteristics of fault zone, cleavage characters of fault zone, drag folds, the reverse "s" fold in the footwall, positive flower structures and small left strike-slip fault, the kinematics characters of fault zone of Sertengshan-Xitieshan are concluded: thrusting in section, left-slip fault in plane and the strike-slip displacement increasing from the west to the east. Thrusting is the main character, so it was named as left-slip oblique-thrusting fault.(4) Through the analysis on the spread of inner structure, thickness change of strata and seismic and geological data in the southern basin of Sertengshan-Xitieshan, this paper discussed the response of oblique-thrust effect on basin. There are coherent between the spread of oblique-thrusting structure, fold and fault structure. There were close relationships between oblique-thrust structure and the reverse "s" structure in the basin. Both of them are result of the left oblique-thrusting.(5) According to the study on seismicic data, sedimentary characteristics, contact relations, incision relation of the faults and strata related to the folds which are associated with the faults, this paper reached the conclusions: the oblique-thrusting structure of Sertengshan-Xitieshan in northern Qaidam basin was formed in middle Jurassic and the left-thrusting fault zone was established in the late Pliocene of Neogene. The formation of the nappe led to sinking of Qaidam massif, nappe thrusting basin depositing persistently and the sedimentary center changed.(6) The geological significance of oblique-thrusting fault of Sertengshan-Xitieshan was discussed in this paper. The oblique-thrusting effect of Sertengshan-Xitieshan is the result of the long distance effction of Himalayan orogenic belt intracontinent subducting, which is of great theory significance for studying regional structural framwork, relations between basins and mountains and oblique-thrusting effect of large-scale fault zone or orogen in northern Qaidam basin. Moreover, the result is of guidance significance for the forecast of combination gas, distributing and formation of nappe metal deposit in northern Qaidam basin. The study on the fault zone will promote the discussion of the rising mechanism of the Tibeteau Plateau.更多还原