【作者】 王清华；

【导师】 杨树锋； 陈汉林；

【作者基本信息】 浙江大学 ， 构造地质学， 2007， 博士

【摘要】 冲断带的变形一方面控制了油气的聚集过程,大部分油气资源是聚集在变形有关的构造圈闭中,另一方面沉积地层的构造变形使得高精度的地震勘探很难获得理想的效果。南天山南缘冲断带是我国西部一条十分重要的冲断造山带。由于其独特的构造位置、优越的地面露头条件与重要的板内变形动力学意义吸引着国内外地学界的浓厚兴趣,使其成为研究陆内造山作用及其横向变化机制的天然实验室。同时,该冲断带内蕴藏着丰富的油气资源,但由于受天山古老造山带多期构造运动的影响,构造变形十分复杂。因此,开展南天山南缘冲断带构造变形特征及控制因素的研究是油气勘探生产中急需解决的实际问题。本文以南天山南缘中西段中国境内的区域为研究范围,包括乌什—柯坪—喀什凹陷北缘。本次研究旨在充分利用地质露头、地震以及非地震等资料的基础上,应用重、磁、电、震联合反演与综合解释、山前逆冲带构造建模、构造平衡剖面等技术,开展南天山南缘中西段构造变形特征及控制因素的研究,建立不同区段的构造地质模型,以此指导该区的构造建模与油气勘探,并为我国西部新生代大陆动力学研究提供基础。通过论文研究,取得了以下成果:(1)首次将南天山山前重力、磁力资料进行拼接处理、数字化处理,并结合露头区的资料和地震资料,开展基底断裂、盖层断裂研究,深化了南天山中西段断裂特征的认识,提出南天山南缘中西段可以划分为乌什冲断带、柯坪冲断带、阿图什冲断带。(2)开展了乌什凹陷与库车坳陷中、新生代的建造和改造关系研究,认为中生代时两者为统一的整体;新生代时由于喀拉玉尔滚断裂的走滑作用而被分隔。同时,建立起更符合实际的乌什冲断带的地质结构与变形样式。(3)利用重、磁力资料,在研究区识别出盖孜与印干西断裂,它们均是古生代以来长期活动的断裂,分别是阿图什冲断带与柯坪冲断带、柯坪冲断带与乌什冲断带的边界断层。(4)提出了南天山中西段山前不同区段构造变形存在空间上和时间上的差异性。东部的乌什冲断带为基底卷入变形样式,柯坪冲断带为叠瓦式冲断样式,而阿图什冲断带为盲冲冲断样式。柯坪地区的构造变形最早,为中新世晚期—上新世,研究区东部与西部变形时间相对稍晚,为更新世—全新世。(5)开展南天山中西段山前各冲断带典型剖面平衡恢复研究,提出了南天山南缘中西段构造变形的缩短量整体呈现由东向西变大的趋势。阿图什褶皱冲断带地层缩短量最大,达到了50.5-63.8%;而研究区东部乌什冲断带的地层缩短量只有14.7-27.1%。(6)建立了南天山南缘中西段各冲断带的变形模式,并探讨了各冲断带变形的控制因素。更多还原

【Abstract】 Structural deformation in fold and thrust belt controls accumulation of oil and gas, and a great number of hydrocarbon accumulates in the structural trap related to structural deformation.On the other hand,structural deformation of deposited strata makes it difficult to obtain ideal seismic data.The fold and thrust belt located in the front of the South Tianshan is a very important structural belt in West China,with particular tectonic setting,convenient observation in field and important significance in dynamics of inner plate,which has attracted many geologist from home and abroad to study its structural deformation.The structural belt has become an natural laboratory for studying intracontinental orogeny and its transverse dynamics and kinematics.There are abundant of oil and gas in the structural belt,and complicated structural deformation resulted from several times tectonic movement in Tianshan area makes it difficult to develop oil and gas exlploration.Research on structural analysis and formation mechanism of fold and thrust belt in the front of the South Tianshan is very crucial to oil and gas exploration.The stuy area in this thesis lies in the southern margin of the South Tianshan belonging to China,including Wushi fold and thrust belt,Keping fold and thrust belt and Artux fold and thrust belt.Research on structure analysis and formation mechanism of fold and thrust belt in the front of the South Tianshan is developed based on field geological,seismic and non-seismic data,by the technology of joint-inversion of gravity,magnetic,electric and seismic data,structure modeling of fold and thrust,structural balanced-section,and structural models of different segments are set up;controlling factors of structural deformation are pointed out. Through the research,the following new points are put forward:(1)The gravitational and magnetic data is merged and digitized for the first time. Combined with field geologic and seismic data,fault system of the fold and thrust belt is studied.According to characteristics of fault and deformation,central and western segments of southern margin of the South Tianshan are divided into three structural belts:Wushi structural belt,Keping structural belt and Artux structural belt.(2)It is put forward for the first time that Wushi Sag and Kuqa depression were connected in Mesozoic and separated in Cenozoic because of strike-slip of Kalayuergun fault.Structural frame and structural style of Wushi fold and thrust belt are set up which measures up to real condition much better.(3)Based on gravitational and magnetic data,Gaizi fault and West Yingan fault are recognized with activity since Palaeozoic,which is repectively the boundary between Artux and Keping fold and thrust belt,Keping and Wushi fold and thrust belt.(4)It is putforward that Structural deformation of central and western segment of South Tianshan are different in space and time.Basement-involved structure is the mainly structural style in Wushi fold and thrust belt,imbricate thrust structure in Keping fold and thrust belt,blind thrust structure in Artux fold and thrust belt.The period of structural deformation in Keping structural belt is late Miocene to Pliocene, and it is Pleistocene to Holocene in Wushi and Artux structural belt.(5)Through the research of structural balanced section,it was found that crustal shortening amount of central and western segments of southern margin of South Tianshan gradually becomes larger from east to west.The crustal shortening amount in Artux structural belt arrives at 50.5-63.8%,only 14.7-27.1%in Wushi structural belt.(6)Structural deformation model of the three fold and thrust belts in the southern margin of South Tianshan is set up and controlling factors of these structural belts are respectively analyzed.更多还原