准噶尔盆地东北缘乌伦古坳陷中生代逆冲推覆构造

乌伦古坳陷位于准噶尔盆地的东北缘,中生代以来逆冲断裂特别发育。本文通过对典型二维地震剖面进行构造解释,结合平衡剖面的正演方法,对乌伦古坳陷内逆冲推覆构造的分带性、分期性和拓展方式及动力过程进行研究。研究认为乌伦古坳陷内部逆冲推覆构造从北向南分为根部带的红岩断阶带、中部带的索索泉凹陷、前锋带的喀拉萨依断裂。剖面平衡结果显示,从晚三叠世到白垩纪,准噶尔盆地东北缘受到自北向南的挤压作用,逆冲断裂整体表现出基底卷入的前展式叠瓦逆冲的特点,具有从北向南拓展规律,即北部断裂活动较早,而南部断裂活动较晚。对比平衡剖面不同时代地层的收缩率变化可知,逆冲断裂活动总体可以划分为4个演化阶段:印支末期、燕山早期、燕山中期和燕山晚期。其中印支期是逆冲体系的启动期;燕山早期为主活动期,逆冲活动波及全区;燕山中期逆冲活动表现为震荡特征;燕山晚期逆冲活动微弱。中生代前期,乌伦古坳陷地区的逆冲体系形成的动力主要来自南阿尔泰造山带持续挤压,中生代后期叠加了北天山造山带自南向北的推覆挤压,使坳陷南部喀拉萨依断裂具有了走滑性质,该走滑活动与准噶尔内部微块体之间发生挤出-逃逸的调节过程有关。     

内蒙古东北部晚二叠世-早三叠世构造演化的新证据：尖子山早三叠世磨拉石的识别

磨拉石是造山带的重要组成部分,利用磨拉石来限定碰撞作用时限是造山带研究的一项重要内容。以内蒙古东北部科右中旗尖子山出露的一套杂色砾岩夹紫红色-灰紫色砂砾岩地层为研究对象,通过对其岩石组合、沉积构造、沉积时代的研究,认为其是一套产于陆内造山背景下前陆盆地的近源磨拉石,地层底部的近源崩塌堆积成因的花岗岩巨砾锆石LA-ICP-MS U-Pb年龄为250±2.9 Ma。结合区域上老龙头组碎屑锆石年龄及三叠纪同碰撞-后碰撞-陆内伸展阶段花岗岩时代的研究,认为该套磨拉石沉积于早三叠世,属下三叠统老龙头组。研究区早三叠世磨拉石的识别,明确了早三叠世存在陆内造山作用,为内蒙古东北部晚二叠世-早三叠世构造演化提供了新证据。     

库车坳陷的地质结构及其对大油气田的控制作用

库车坳陷是在晚二叠世之前的古生代褶皱基底上历经晚二叠世-三叠纪的前陆盆地、侏罗-古近纪的伸展坳陷盆地和新近纪-第四纪陆内前陆盆地的演化而形成的。基底中的软弱层、侏罗系煤层和古近系库姆格列木组与新近系吉迪克组膏盐(泥)岩构成了自山前向盆地内部逐渐抬升的滑脱面,与自山前向盆地内部逐渐趋缓的地表面构成楔形体。该楔形冲断体的内部结构具有"垂向分层、横向分带与纵向分段"特点,NW向的阿瓦特-喀拉玉尔滚和NE向的库车横向构造转换带将其分割为乌什、拜城与阳霞3个构造区段。构造层发育特点决定了库车坳陷发育三叠-侏罗系的区域展布的有效烃源岩和(侏罗系、)白垩系-第三系储盖组合;分层变形特点导致盐下层形成叠瓦冲断构造组合,冲断层成为油源断层;叠瓦式的冲断层相关褶皱背斜组合导致了复式天然气聚集区带的形成,即在大北-克拉苏式的构造带上每一冲断层相关褶皱背斜带独立成藏,复合连片形成复式油气聚集(区)带,目前拜城北、克深、克拉苏背斜带已呈现这种趋势;撕裂断层则决定着构造带上具体的油气富集区段。库车坳陷油气资源丰富,地质结构特点决定了不同类型油气田分布的分区性。     

中扬子地块宜昌斜坡白垩系陆内挤压盆地的断-坳结构

宜昌斜坡残留的白垩系盆地是认识中扬子地块白垩纪构造演化的一个窗口.基于对白垩系露头的构造-沉积特征的观察,并结合二维地震剖面的构造-地层解释,厘定了宜昌斜坡白垩系盆地的构造属性和沉积充填特征,构建了白垩系陆内挤压盆地的挤压断-坳结构.宜昌斜坡白垩系盆地是由天阳坪逆冲断裂带控制的陆内挤压盆地.下白垩统盆地为同造山期的挤压断陷,充填有扇三角洲-湖泊沉积体系;上白垩统盆地为后造山期的挤压坳陷,充填了冲积扇-辫状河-风成-浅水含膏湖泊沉积体系.宜昌斜坡和湘鄂西弧形带的上白垩统盆地属于陆内挤压盆地的挤压坳陷,揭示中扬子地块由挤压向伸展构造体制转换的起始时间是新生代.      

聂拉木县幅地质调查新成果及主要进展

发现中-晚三叠世鱼龙化石、三叠系和侏罗系珊瑚-海绵生物礁灰岩,识别出白垩系与侏罗系层序不整合界面,查证并获取若干二叠系大陆裂谷型火山岩和早白垩世岛弧型火山岩新的资料.在综合研究地层古生物、层序地层与沉积相、磁性地层、岩浆岩、变质岩、区域构造等资料的基础上,将测区地质发展演化分为:前奥陶纪基底形成、奥陶纪-泥盆纪稳定陆表海、石炭纪-侏罗纪离散型被动大陆边缘、白垩纪-古近纪汇聚型前陆盆地、新近纪-第四纪后造山隆升5个阶段.     

聂拉木县幅地质调查新成果及主要进展

发现中-晚三叠世鱼龙化石，三叠系和侏罗系珊瑚-海绵生物礁灰岩，识别出白垩系与侏罗系层序不整合界面，查证并获取若干三叠系大陆裂谷型火山岩和早白垩世岛弧型火山岩新的资料，在综合研究地层古生物，层序地层与沉积相，磁性地层，岩浆岩，变质岩，区域构造等资料的基础上，将测区地质发展演化分为：前奥陶纪基底形成，奥陶纪-泥盆纪稳定陆表海，石炭纪-侏罗纪离散型被动大陆边缘，白垩纪-古近纪汇聚型前陆盆地，新近纪-第四纪后造山隆升5个阶段。     

准噶尔盆地顶山地区微量元素地球化学特征分析

<正>顶山地区位于准噶尔盆地北缘乌伦古坳陷中红岩断阶与索索泉凹陷的交接部位,北邻乌伦古河,西邻德南、石英滩凸起,南至三个泉断裂,东达青格里底山。区内的构造主要为NW向的断裂构造,最主要的是吐丝托依拉断裂,其次为黄花沟断裂、乌伦古北断裂、乌伦古南断裂、陆东北侧断裂及索一红南断裂。吐丝托依拉断裂为一     

Basin-Mountain Coupling Syestem and Its Sedimentary Response in Sichuan Analogous Foreland Basin

依据四川盆地晚三叠世须家河期至白垩纪盆地构造和沉积演化史的综合分析结果,认为该盆地属于发育在大型周缘前陆盆地基础上的陆内压性叠合盆地,具类前陆盆地性质.盆地形成和演化受周边龙门山、米仓山-大巴山和雪峰山3个造山带多期次非同步异方位的逆冲推覆活动控制,可划分为受盆缘造山带逆冲推覆作用控制的川西、川东北和川东南3个盆-山耦合次系统,区域上构成了独具特色的“三坳围一隆”构造-沉积格局.对应各造山带异方位的交替逆冲推覆活动,盆-山耦合过程又可划分为早期周缘前陆盆地(T3m→T3 xt)、中期类前陆盆地(T3x→J3)、晚期萎缩衰亡(K)3个演化阶段.各演化阶段盆-山耦合过程的沉积学响应具有特征的异同性:差异性为对应各造山带逆冲推覆应力方位的变化,各亚阶段沉降-沉积中心位置各异,往复迁移于川西、川东北和川东南3个坳陷带;相似性为各次系统地层分布都呈自前缘坳陷带向前陆斜坡带和前陆隆起带上超减薄变细的楔状体,具有相似的沉积组合、相带展布和油气地质特征.     

四川盆地盆-山耦合系统和沉积响应特征

依据四川盆地晚三叠世须家河期至白垩纪盆地构造和沉积演化史的综合分析结果,认为该盆地属于发育在大型周缘前陆盆地基础上的陆内压性叠合盆地,具类前陆盆地性质。盆地形成和演化受周边龙门山、米仓山-大巴山和雪峰山3个造山带多期次非同步异方位的逆冲推覆活动控制,可划分为受盆缘造山带逆冲推覆作用控制的川西、川东北和川东南3个盆-山耦合次系统,区域上构成了独具特色的"三坳围一隆"构造-沉积格局。对应各造山带异方位的交替逆冲推覆活动,盆-山耦合过程又可划分为早期周缘前陆盆地(T3m→T3xt)、中期类前陆盆地(T3x→J3)、晚期萎缩衰亡(K)3个演化阶段。各演化阶段盆-山耦合过程的沉积学响应具有特征的异同性:差异性为对应各造山带逆冲推覆应力方位的变化,各亚阶段沉降-沉积中心位置各异,往复迁移于川西、川东北和川东南3个坳陷带;相似性为各次系统地层分布都呈自前缘坳陷带向前陆斜坡带和前陆隆起带上超减薄变细的楔状体,具有相似的沉积组合、相带展布和油气地质特征。     

江西萍乐凹陷构造-沉积演化的基本特征及对找煤预测的启示

中新生代以来,江西萍乐(萍乡-乐平)凹陷带的构造-沉积演化经历了三期四个阶段,即:印支期大规模的推覆、燕山早期晚三叠世末的基底拆离和褶皱-逆冲以及早侏罗世末的盖层滑脱、喜山期新近纪盖层和基底的滑覆,反映盆地性质具有断(裂)陷与坳陷的多次转换特征.构造运动对煤层的控制也表现为坳陷导致煤系地层盖层加厚、埋藏加深及错断、重复...     

松辽盆地北部构造演化对砂岩型铀矿床成矿的控制作用

松辽盆地构造演化划分为前中生代克拉通基底演化、晚侏罗世挤压火山穹窿演化、早白垩世伸展断陷、晚白垩世早期热冷却坳陷、晚白垩世晚期反转褶皱隆升萎缩剥蚀、古近纪伸展断陷隆升剥蚀及新近纪—第四纪挤压坳陷等7个演化阶段。本文系统讨论了松辽盆地北部构造演化与铀成矿作用的关系,指出晚白垩世早期冷却坳陷、晚白垩世晚期反转褶皱隆升萎缩剥蚀、古近纪伸展断陷隆升剥蚀3个阶段为区内主要铀成矿阶段。铀矿化的分布受基底断裂及反转构造带联合控制。松辽盆地北部构造演化对各构造分区铀矿床成矿类型具有明显的控制作用：西部斜坡区以寻找"古层间氧化"型、层间氧化型砂岩型铀矿床为主要类型;中央坳陷区及东北隆起区应围绕大庆长垣、绥棱背斜带等构造剥蚀天窗寻找"钱家店"式砂岩型铀矿床;北部倾没区及东北隆起区盆缘以寻找层间氧化型砂岩型铀矿床为主要类型。     

鲁北济阳坳陷沾化凹陷东部潜山的发育及油气成藏控制因素

通过对沾化凹陷东部主要断裂发育演化的特征和主要地震测线的平衡剖面、伸展率分析,对该地区潜山发育过程及其与盆地演化的关系进行了研究,并就潜山油气成藏的控制因素进行了分析。结果表明,沾化凹陷东部潜山发育可以划分为早—中三叠世、晚三叠世、早—中侏罗世的潜山发育前期,晚侏罗世—白垩纪的潜山发育期,古近纪的潜山改造、定型期和新近纪—第四纪的潜山成藏期,断裂活动是本区潜山形成演化的主控因素。沾化凹陷东部潜山油气成藏主要受控于该区中、新生代盆地的叠合关系,中生代凸起和古近纪凹陷的叠合部位是最有利的潜山油气成藏区,中生代凸起和古近纪凸起的叠合部位不利于潜山成藏,往往形成潜山披覆背斜油气藏。     

酒泉中新生代断坳叠合盆地及控油作用

基于盆地大地构造背景、盆地几何形态、沉积构造特征、古地温及火山岩等沉积盆地鉴别标志,认为酒泉盆地为中新生代断坳叠合盆地,中生代早白垩世属伸展断陷盆地,新生代为陆内挤压坳陷盆地和陆内前陆盆地。盆地叠合类型为陆内坳陷盆地和陆内前陆盆地与断陷盆地叠合,叠合方式总体为正交式叠合,其中陆内坳陷盆地与断陷盆地叠合方式可以划分为披盖叠合型、局部叠合型、未叠合型3类,按照断陷盆地与陆内前陆盆地构造单元叠合位置,将陆内前陆盆地与断陷盆地叠合方式划分为前陆冲断带与次级凹陷的叠合、前陆坳陷与次级凹陷的叠合、前陆斜坡与次级凹陷的叠合、隆后坳陷与次级凹陷的叠合4个亚类。中新生代盆地叠合控制了酒泉盆地油气成藏,早白垩世断陷盆地控制了烃源岩分布,决定了不同次级凹陷(含油气系统的)范围和优劣,中新生代盆地叠合不仅加速了烃源岩成熟,为油气运移提供了强大动力,而且对构造圈闭、油气运移通道的形成、储层物性的改善(裂缝的发育)起关键的作用。由于不同的次级凹陷叠合方式和叠合强度的差异,导致了油气运移、聚集成藏差异,油藏特征和油气富集程度不同。     

鲁北济阳坳陷沾化凹陷东部潜山的发育及油气成藏控制因素

通过对沾化凹陷东部主要断裂发育演化的特征和主要地震测线的平衡剖面、伸展率分析,对该地区潜山发育过程及其与盆地演化的关系进行了研究,并就潜山油气成藏的控制因素进行了分析.结果表明,沾化凹陷东部潜山发育可以划分为早-中三叠世、晚三叠世、早-中侏罗世的潜山发育前期,晚侏罗世-白垩纪的潜山发育期,古近纪的潜山改造、定型期和新近纪-第四纪的潜山成藏期,断裂活动是本区潜山形成演化的主控因素.沾化凹陷东部潜山油气成藏主要受控于该区中、新生代盆地的叠合关系,中生代凸起和古近纪凹陷的叠合部位是最有利的潜山油气成藏区,中生代凸起和古近纪凸起的叠合部位不利于潜山成藏,往往形成潜山披覆背斜油气藏.     

Mesozoic-Cenozoic Basin Features and Evolution of Southeast China

The Late Triassic to Paleogene(T_3-E) basin occupies an area of 143100 km~2,being the sixth area of the whole of SE China;the total area of synchronous granitoid is about 127300 km~2;it provides a key for understanding the tectonic evolution of South China.From a new 1:1500000 geological map of the Mesozoic-Cenozoic basins of SE China,combined with analysis of geometrical and petrological features,some new insights of basin tectonics are obtained.Advances include petrotectonic assemblages, basin classification of geodynamics,geometric features,relations of basin and range.According to basin-forming geodynamicai mechanisms,the Mesozoic-Cenozoic basin of SE China can be divided into three types,namely:1) para-foreland basin formed from Late Triassic to Early Jurassic(T_3-J_1) under compressional conditions;2) rift basins formed during the Middle Jurassic(J_2) under a strongly extensional setting;and 3) a faulted depression formed during Early Cretaceous to Paleogene (K_1-E) under back-arc extension action.From the rock assemblages of the basin,the faulted depression can be subdivided into a volcanic-sedimentary type formed mainly during the Early Cretaceous(K_1) and a red -bed type formed from Late Cretaceous to Paleogene(K_2-E).Statistical data suggest that the area of all para-foreland basins(T_3-J_1) is 15120 km~2,one of rift basins(J_2) occupies 4640 km~2,and all faulted depressions equal to 124330 km~2 including the K_2-E red-bed basins of 37850 km~2.The Early Mesozoic (T_3-J_1) basin and granite were mostly co-generated under a post-collision compression background, while the basins from Middle Jurassic to Paleogene(J_2-E) were mainly constrained by regional extensional tectonics.Three geological and geographical zones were surveyed,namely:1)the Wuyishan separating zone of paleogeography and climate from Middle Jurassic to Tertiary;2)the Middle Jurassic rift zone;and 3)the Ganjiang separating zone of Late Mesozoic volcanism.Three types of basin-granite relationships have been identified,including compressional(a few),strike-slip(a few), and extensional(common).A three-stage geodynamical evolution of the SE-China basin is mooted:an Early Mesozoic basin-granite framework;a transitional Middle Jurassic tectonic regime; intracontinental extension and red-bed faulted depressions since the Late Cretaceous.     

华北北部中新生代构造体制的转换过程

华北北部位于古亚洲和太平洋两大全球性构造域的交叠部位,其中新生代断裂演化、区域性不整合界面和盆地演化的地质事实显示华北北部中新生代存在5个挤压作用时期。自老至新为:①中三叠世末挤压期(老虎沟组或杏石口组前挤压期,峰值年龄 ≥ 215Ma);②早侏罗世末挤压期(海房沟组或九龙山组前挤压期,峰值年龄 ≥ 178Ma);③晚侏罗世末挤压期(义县组或东岭台组前挤压期,峰值年龄 ≥ 135Ma);④晚白垩世末挤压期(古近系前挤压期,峰值年龄65Ma);⑤古近纪末挤压期(新近纪前挤压期,峰值年龄25Ma).5个挤压期在时间上相对较短,并为6个时间较长,构造运动相对和缓或伸展的成盆沉积期一一隔开。6个成盆沉积期包括:早中三叠世、晚三叠世-早侏罗世、中晚侏罗世、白垩纪、古近纪、新近纪-第四纪。其中,中晚侏罗世、白垩纪、古近纪、新近纪-第四纪具有明显的伸展作用特征。也就是说,华北北部中新生代的构造演化过程是在前中生代华北克拉通岩石圈基础上发育起来的克拉通内(陆内或板内)成盆沉积与挤压变形的交替演化过程,在这一构造演化过程中,挤压作用和伸展作用均占有重要位置,总体来讲,挤压作用由强变弱,伸展作用由弱变强。伸展作用持续的时间长,挤压作用持续时间则相对较短。挤压作用和伸展作用交替出现,挤压构造和伸展构造间互发育。华北北部中新生代这种构造体制的转换过程,记录了从古亚洲洋构造域汇聚构造体制向太平洋构造域俯冲构造体制转换的大陆动力学过程。      

定远凹陷形成的区域构造背景及其演化过程

定远凹陷上古生界构造归属及其构造演化过程,对下一步该地区煤炭资源评价与非常规天然气选区具有关键性的意义。文章利用最新的地球物理与钻探成果,应用构造解析及区域对比等方法,结合区域构造规律与前人相关认识,对定远凹陷构造特征、上古生界构造归属及中生代以来的构造演化过程进行了详细的论述,其结果认为定远凹陷内发育的上古生界煤系地层属于淮南煤田中部复式向斜构造带东部的延伸。该凹陷受大别造山带隆起及郯庐断裂带中、新生代走滑活动影响,分别经历了印支期（T3）前陆变形、早中侏罗世（J1+2）相对隆起、晚侏罗世（J3）末期至早白垩世初期（K1初期）郯庐断裂带左行走滑改造、早白垩世期间（K1）至古近纪(E）伸展改造、古近纪末期挤压反转以及新近纪（Q）—第四纪（N）坳陷式均匀沉降六个主要演化阶段。     

Mesozoic tectonic evolution of the Southeast China Block: New insights from basin analysis

In order to better understand the Mesozoic tectonic evolution of Southeast China Block (SECB in short), this paper describes geological features of Mesozoic basins that are widely distributed in the SECB. The analyzed data are derived from a regional geological investigation on various Mesozoic basins and a recently compiled 1:1,500,000 geological map of Mesozoic–Cenozoic basins. Two types of basin are distinguished according to their tectonic settings, namely, the post-orogenic basin (Type I) and the intracontinental extensional basin (Type II); the latter includes the graben and the half-graben or faulted-depression basins. Our studies suggest that the formation of these basins connects with the evolution of geotectonics of the SECB. The post-orogenic basin (Type I) was formed in areas from the piedmont to the intraland during the interval from Late Triassic to Early Jurassic; and the formation of the intracontinental extensional basin (Type II) connects with an intracontinental crustal thinning setting in the Late Mesozoic. The graben basin was generated during the Middle Jurassic and is associated with a bimodal volcanic eruption; and the half-graben or faulted-depression basin, filled mainly by the rhyolite, tuff and sedimentary rocks during Early Cretaceous, is occupied by the Late Cretaceous–Paleogene red-colored terrestrial clastic rocks. We noticed that the modern outcrops of numerous granites and basins occur in a similar level, and the Mesozoic granitic bodies contact with the adjacent basins by large normal faults, suggesting that the modern landforms between granites and basins were yielded by the late crustal movement. The modern basin and range framework was settled down in the Cretaceous. Abundant sedimentary structures are found in the various basins, from that the deposited environments and paleo-currents are concluded; during the Late Triassic–Early Jurassic time, the source areas were situated to the north and northeast sides of the outcrop region. In this paper, we present the study results on one geological and geographical separating unit and two separating fault zones. The Wuyi orogenic belt is a Late Mesozoic paleo-geographically separating unit, the Ganjiang fault zone behaves as the western boundary of Early Cretaceous volcanic rocks, and the Zhenghe–Dapu fault zone separates the SE-China Coastal Late Mesozoic volcanic-sedimentary basins and the Wuyi orogenic belt. Finally, we discuss the geodynamic mechanisms forming various basins, proposing a three-stage model of the Mesozoic sedimentary evolution.     

Mesozoic intracontinental orogeny in the Qinling Mountains,central China

The Qinling Orogenic belt has been well documented that it was formed by multiple steps of convergence and subsequent collision between the North China and South China Blocks during Paleozoic and Late Triassic times. Following the collision in Late Triassic times, the whole range evolved into an intracontinental tectonic process. The geological, geophysical and geochronological data suggest that the intracontinental tectonic evolutionary history of the Qinling Orogenic Belt allow deduce three stages including strike-slip faulting during Early Jurrassic, N-S compressional deformation during Late Jurassic to Early Cretaceous and orogenic collapse during Late Cretaceous to Paleogene. The strike-slip faulting and the infills in Early Jurassic along some major boundary faults show flower structures and pull-apart basins, related to the continued compression after Late Triassic collision between the South Qinling Belt and the South China Block along the Mianlue suture. Late Jurassic to Early Cretaceous large scale of N-S compression and overthrusting progressed outwards from inner of Qinling Orogen to the North China Block and South China Block, due to the renewed southward intracontinental subduction of the North China Block beneath the Qinling Orogenic Belt and continuously northward subduction of the South China Block, respectively. After the Late Jurassic-Early Cretaceous compression and denudation, the Qinling Orogenic Belt evolved into Late Cretaceous to Paleogene orogen collapse and depression, and formed many large fault basins along the major faults.     

柴北缘东段构造应力场数值模拟及构造演化模式探讨

为了明确柴北缘东段晚古生代至中生代的构造演化历史,探讨石炭系—侏罗系地层缺失的原因,本文应用有限单元 法 模 拟 了 柴 北 缘 东 段 印 支 期 ( 三 叠 纪 )、 燕 山 早 期 ( 侏 罗 纪 )、 燕 山 晚 期 ( 白 垩 纪 ) 的 构 造 应 力 场 , 分 析 了 该 区 不 同 时 期 的 主应力与剪应力分布特征。根据库仑及格里菲斯岩石破裂准则预测了古构造的存在并探讨了地层缺失的原因。研究结果表 明:三叠纪,柴北缘东段在印支期不均匀分布的最大主应力与右旋剪应力共同作用下,发育两排近东西走向的背斜凸起, 造成石炭系—二叠系在各地区遭受不同程度的剥蚀;侏罗纪,在燕山早期拉张应力场作用下,由早—中侏罗世的断陷盆地 逐渐演化为晚侏罗世的坳陷盆地,欧南地区为继承性隆起区未接受沉积;白垩纪,受晚期燕山运动影响,应力场逐渐由拉 张转变为挤压,构造反转,逆冲断裂复活,绿梁山、锡铁山、埃姆尼克山、欧隆布鲁克山等主要山体隆升,遭受剥蚀,柴 北缘东段中生代盆地演化终止。