渤海湾盆地临清坳陷东部上侏罗统—下白垩统剥蚀量恢复与原型盆地*

渤海湾盆地临清坳陷东部自中生代以来经历了多次构造运动,不同构造时期盆地性质也不相同。本次研究对临清坳陷东部自晚侏罗世以来的构造演化历史进行了分析,恢复了上侏罗统—下白垩统的地层剥蚀量和原始地层厚度,在此基础上结合同一时期的断裂系统图,对盆地发育特征进行了初步研究。结果表明：临清坳陷东部晚侏罗世—早白垩世处于断陷盆地发育阶段;地层剥蚀程度的强弱主要受燕山晚期运动所形成的各种构造的控制,剥蚀厚度呈NE向大小相间分布;晚侏罗世—早白垩世盆地展布方向为NNE向,地层展布主要受断层控制,厚度中心均位于断层上盘。     

柴达木盆地北缘中生代盆地性质研究——对大柴旦凹陷的解剖

柴达木盆地北部地区的中生代地层是柴达木盆地油气勘探的重点层系之一.利用地震剖面解释成果和野外地质资料绘制了侏罗纪与白垩纪的地层残余分布图和断裂分布图;利用平衡剖面对地震剖面进行了平衡恢复.恢复了侏罗纪与自垩纪的原始与剥蚀后形态.通过对中生代各期(主要是侏罗纪和白垩纪)残余地层、断裂的分布和地震剖面构造演化的综合分析,认为柴达木盆地北部地区中生代经历了三个不同性质的盆地演化阶段:早侏罗世为伸展环境下的(箕状)断陷盆地,主要表现为一系列小型断陷盆地群;中侏罗世-早自垩世为伸展型坳陷盆地;晚白垩世末盆地受挤压整体隆升,形成古隆起.     

下扬子中生代沉积盆地演化

通过对下扬子地区各地层分区中生代岩石地层序列、沉积建造详细分析以及生物地层与年代地层划分对比, 在盆地原型恢复、盆地充填序列和岩相古地理综合分析的基础上, 划分出下扬子陆块中生代不同时段的5类沉积盆地: 陆表海(T_1-2)、周缘前陆盆地(T₃-J₁)、压陷盆地(T₃-J₂)、断陷盆地(J₃-K)和拉分盆地(J₃-K), 初步建立了下扬子陆块中生代沉积盆地时空分布格架.分析了下扬子中生代盆地沉积大地构造环境演化历程: 三叠纪-早侏罗世为与特提斯海演化相关的构造阶段, 分为早三叠世-中三叠世陆表海和晚三叠世-早侏罗世前陆盆地2个亚阶段; 中侏罗世-白垩纪转化为滨太平洋构造阶段, 中侏罗世以挤压构造背景为主, 大部分地区为隆升剥蚀区, 晚侏罗世-白垩纪为强裂伸展拉张期, 发育了一系列北东向火山-沉积断陷盆地和拉分盆地, 盆-岭构造格局形成.      

济阳坳陷中生代盆地演化及其与新生代盆地叠合关系探讨

济阳坳陷中生代盆地演化受控于欧亚构造域的板块拼接挤压和滨太平洋构造域及其郯庐断裂活动两种动力学背景。早、中三叠世,作为华北大型内陆沉积盆地的一部分,沉积了近2000 m厚的地层;晚三叠世,主要受控于扬子板块与华北板块挤压碰撞所产生的挤压应力场,处于抬升剥蚀状态,早、中三叠世沉积的地层几乎剥蚀殆尽,并开始发育多条NW向逆冲断层;早、中侏罗世是对晚三叠世挤压逆冲断层和褶皱所造成的本区地势高低起伏的一个截凸填凹、填平补齐的过程;晚侏罗世—白垩纪,受郯庐断裂左行走滑的影响,济阳坳陷区前期形成的NW向逆冲断层,发生构造反转,反向伸展,形成了一系列半地堑。控盆断层为NW向的中生代盆地,与控盆断层为NE(或NNE)向的新生代盆地里相干型叠合,可划分出中坳新拗、中坳新隆、中隆新坳、中隆新隆4种叠合单元类型,不同类型的叠合单元经历了不同的沉降史,具有不同的石油地质意义。     

北黄海盆地构造演化特征分析

依据最新油气资源调查资料,在简述北黄海盆地区域构造特征的基础上,重点分析了盆地的沉降史与构造演化特征。研究表明:(1)北黄海盆地的基本沉降曲线型式为7段折线状,其中晚侏罗世、早白垩世、始新世、渐新世、新近纪为曲线下降段,代表盆地5幕较明显的沉降;晚白垩世—古新世以及中新世早期为曲线上升段,反映盆地的抬升剥蚀。(2)盆地沉降作用自中生代至新生代总体由东向西迁移,东部坳陷以中生代沉降作用最为显著,中部坳陷主沉降期为始新世,而西部坳陷的快速沉降主要发生在始新世,并一直持续到渐新世。(3)盆地构造演化大致可划分为中生代断陷盆地、古近纪叠加断陷盆地以及新近纪坳陷盆地等3大发展阶段,其中,中生代断陷盆地发育阶段是北黄海盆地油气勘探研究的重点。     

库车坳陷中生界陆相层序地层格架与盆地演化

根据库车坳陷野外露头和钻井地层对比与沉积相分析,建立了库车坳陷中生界陆相层序地层的格架,总结了陆相盆地层序地层发育的特点,指出了多期叠合盆地陆相层序发育和横向对比的复杂性.将库车坳陷中生界划分了5个二级构造层序,每个层序分别由低位、湖侵和高位体系域组成.低位体系域多为巨厚的冲积扇、扇三角洲和辫状河三角洲沉积体系,代表较强烈的造山活动期的沉积响应.湖侵体系域主要为辫状河三角洲前缘-滨浅湖沉积体系,代表造山运动间歇期的沉积响应.高位体系域多为冲积扇-辫状河三角洲平原沉积体系,代表较弱的造山活动期的沉积响应.根据库车坳陷层序演化,建立了陆相盆地的3种盆地模式,即强挤压沉陷盆地,以早-中三叠世和晚第三-第四纪为代表;弱挤压沉陷盆地,以晚侏罗-早白垩世为代表;造山后剥蚀反弹盆地,以晚三叠世-早、中侏罗世和早第三纪为代表.     

江汉盆地当阳向斜区主要不整合面剥蚀厚度

本文利用磷灰石裂变径迹、(U-Th Sm)/He及镜质体反射率Ro％等古温标方法综合分析了江汉盆地当阳向斜区主要不整合面剥蚀厚度.结果表明:发育于古近纪末期不整合面T1界面累积剥蚀厚度超过1000m,且局部正反转区域如谢家湾断褶带等则遭受更大规模的剥蚀,剥蚀厚度可能超过2000m,而发育于晚侏罗世一早白垩世的不整合面T11界面累积剥蚀厚度超过4000m,且主要是晚侏罗世早白垩世构造事件的结果,表明该期剥蚀量明显大于古近纪末T1界面剥蚀量;晚三叠世—侏罗纪期间,当阳地区发育前陆坳陷带,侏罗纪堆积体具有明显东厚西薄的楔形体特征,位于盆地东部的前渊区沉积厚度可超过5000m;包括现今三叠系和侏罗系出露区以及江陵凹陷局部断隆区在内的前白垩系在侏罗纪前陆坳陷带发育时期达到最大埋深和最高古温度,其Ro％主要是该期获得的;晚白垩世—古近纪发育的断陷盆地范围可能远比现今残留盆地分布广,江陵凹陷上白垩统—古近系厚度超过9000m,其中古近系可能超过7000m,而在河溶凹陷谢家湾断褶带古近系厚度可超过3300m.     

库车坳陷东部晚白垩世古隆起及构造应力场恢复

库车坳陷东部具有丰富的油气资源,其构造变形机制与南天山造山带密切相关。综合采用露头共轭节理及白垩系残余厚度分布,分析了库车坳陷东部晚白垩世古隆起特征及构造应力场属性。吐格尔明、克孜勒努尔沟、库车河、卡普沙良河、吉迪克以及库车河西6条剖面的共轭节理分析表明,库车坳陷东部新生代构造挤压应力为NNW-SSE向,而中生代的构造挤压应力为NE-SW向。原型盆地恢复显示,库车坳陷白垩纪的沉积中心大致位于大北1井―吐北2井―克拉2井一线,且发育秋里塔格―新和―牙哈―提尔根古隆起带,白垩系原始沉积厚度总体上北厚南薄。在晚白垩世区域抬升剥蚀的构造背景下,坳陷东部受压隆升遭受剥蚀,白垩系残余厚度减薄,呈西厚东薄的趋势。位于坳陷东部的吐格尔明背斜在石炭纪―三叠纪为一个长期存在的继承性沉积古隆起,晚白垩世进一步隆升形成构造古隆起,背斜周缘的白垩系残余厚度进一步减薄。吐格尔明背斜和背斜周缘白垩系残余厚度等值线以及库北1井和库车河剖面周缘白垩系残余厚度等值线的长轴方向均为NW-SE向,进一步证实了库车坳陷东部晚白垩世的构造应力为NE-SW向。库车坳陷东部晚白垩世古隆起与构造应力场属性主要与特提斯造山带中地体增生和拼贴作用导致的特提斯北缘盆地群中发生的区域性抬升有关。     

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。     

沾化凹陷东北部中新生代盆地演化过程研究

依据层长守恒原则对沾化凹陷东北部北东和北西向,各3条连井地震剖面进行了平衡剖面恢复,并分析了各剖面在地质历史时期内伸展率的变化特征,以了解该地区中、新生代盆地发育演化特征。沾化凹陷东北部中、新生代盆地演化可以划分为如下几个主要阶段:早—中三叠世为大型内陆坳陷发育阶段,地层横向沉积稳定;晚三叠世本区整体挤压抬升剥蚀,并开始发育北西向逆冲断层;早—中侏罗世为对前期地势高差起伏填平补齐的均夷化过程,地层沉积具充填-披覆式特征;晚侏罗世—白垩纪原北西向逆冲断层负向反转,转为张性伸展,本区进入断陷盆地发育阶段,局部发育有挤压逆冲构造;古近纪本区仍为断陷盆地发育阶段,除北西向断层继承性活动外,大量北东(东)向正断层开始活动;新近纪本区进入区域性坳陷沉降阶段。      

150 Million year history of North China Craton disruption preserved in Mesozoic sediments of the Ordos basin

ABSTRACT

The Ordos Basin, situated in the western part of the North China Craton, preserves the 150-million-year history of North China Craton disruption. Those sedimentary sources from Late Triassic to early Middle Jurassic are controlled by the southern Qinling orogenic belt and northern Yinshan orogenic belt. The Middle and Late Jurassic deposits are received from south, north, east, and west of the Ordos Basin. The Cretaceous deposits are composed of aeolian deposits, probably derived from the plateau to the east. The Ordos Basin records four stages of volcanism in the Mesozoic–Late Triassic (230–220 Ma), Early Jurassic (176 Ma), Middle Jurassic (161 Ma), and Early Cretaceous (132 Ma). Late Triassic and Early Jurassic tuff develop in the southern part of the Ordos Basin, Middle Jurassic in the northeastern part, while Early Cretaceous volcanic rocks have a banding distribution along the eastern part. Mesozoic tectonic evolution can be divided into five stages according to sedimentary and volcanic records: Late Triassic extension in a N–S direction (230–220 Ma), Late Triassic compression in a N–S direction (220–210 Ma), Late Triassic–Early Jurassic–Middle Jurassic extension in a N–S direction (210–168 Ma), Late Jurassic–Early Cretaceous compression in both N–S and E–W directions (168–136 Ma), and Early Cretaceous extension in a NE–SW direction (136–132 Ma).     

羌塘盆地中生代构造属性

通过对羌塘盆地南北两侧构造带地质特征、构造演化历程及盆地内部中生代地层充填特征的分析,探讨了羌塘盆地中生代构造属性及地球动力学机制。研究表明:羌塘盆地经历了早、中三叠世前陆盆地,晚三叠世早、中期被动陆缘盆地,晚三叠世晚期—侏罗纪羌北前陆盆地和羌南陆被动陆缘裂陷—坳陷盆地及早白垩世前陆盆地等地质演化历程;盆地南北边界构造带复杂而有序的地球动力学环境和构造演化,决定了羌塘盆地中生代为一复杂的多旋回叠合盆地。     

鄂尔多斯盆地中生代地层剥蚀量估算及其地质意义

盆地演化中地层的沉积与剥蚀及盆地的历史构造形态变动是盆地分析及其矿产富集的重要影响因素。本文考虑到盆地西部白垩系的声波时差资料的分段性和估算中生代三叠纪以来抬升剥蚀事件强度所需选择合理方法的重要性,采用钻井分层资料“点连线,线线相交闭合”方式,应用以地层对比为主的方法估算了三叠纪以来4期地层抬升并遭受剥蚀的剥蚀量。估算结果发现,白垩纪末期为三叠纪以来最强烈一期全盆抬升剥蚀事件,三叠纪末期、中侏罗世和侏罗纪末期等3期剥蚀事件相对较弱。剥蚀强度分布与盆地演化模拟结果表明,盆地自三叠纪以来的构造变动表现为一掀斜过程;对盆地三叠系油气生成、运聚的影响分析认为,三叠系烃源岩在晚侏罗世前已生烃,掀斜构造演化过程使油气运移指向盆地东部及东南地区。     

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.     

鲁西隆起晚中生代盆地重矿物组合分析及其构造响应

本文以鲁西隆起区盆地及周边盆地砂岩中碎屑重矿物为研究对象,通过重矿物的稳定性分析,以及通过不同源区重矿物组合的差异,探讨了鲁西隆起及周边地区晚中生代以来的物源及构造演化过程。研究结果显示,鲁西盆地中生代早期早中侏罗纪时期主要源区为鲁西隆起,中晚侏罗纪时期主要物源为胶东地区和鲁西隆起,而早白垩世时期主要物源为胶东地区,其次才是鲁西隆起。晚白垩世沂沭断裂带盆地物源主要是鲁西隆起和胶东地区,鲁西隆起贡献量大于胶东地区。重矿物的稳定性也折射出源区构造演化历史。早-中侏罗世至中-晚侏罗世,鲁西盆地重矿物物源由鲁西隆起向胶东地区的显著转变,暗示着苏鲁造山带自三叠纪形成之后,经折返抬升,至晚侏罗世之前已经到达地表。重矿物的含量变化显示,早白垩世中期和晚白垩世中期鲁西盆地内沉积了大量的鲁西变质岩矿物组合,并且不稳定重矿物含量急剧增加,我们推测鲁西在早白垩世晚期、晚白垩世中期存在两次构造抬升。     

Radiolarian biochronology of Mesozoic deep-water successions in NW Syria and Cyprus: implications for south-Tethyan evolution

ABSTRACT New radiolarian biostratigraphical data have shed light on the Mesozoic tectonic evolution of South-Tethys in the Baer–Bassit region of NW Syria. Radiolarian assemblages of Late Triassic, Middle Jurassic and Early Cretaceous age were extracted from radiolarites in five measured sections. The results are compared with published radiolarian ages from the Mamonia Complex, western Cyprus. These two areas are interpreted as preserved fragments of the conjugate margins of a small South Tethyan oceanic basin formed by Triassic rifting. In the southerly (i.e. Arabian) margin, proximal successions were dominated by shallow-water-derived carbonate, whereas distal successions reveal seamount-type alkaline/peralkaline volcanism, dated as both Late Triassic and Middle Jurassic–Early Cretaceous. Along the inferred northern margin (i.e. western Cyprus) proximal successions are dominantly terrigenous, whereas distal settings include Late Triassic oceanic crust and seamount-type lavas.     

Migration of Depocenters and Accumulation Centers and its Indication of Subsidence Centers in the Mesozoic Ordos Basin

Based on the integrated study of structure attributions and characteristics of the original basin in combination with lithology and lithofacies, sedimentary provenance analysis and thickness distribution of the Mesozoic Ordos Basin, it is demonstrated that the depocenters migrated counterclockwise from southeast to the north and then to the southwest from the Middle-Late Triassic to the Early Cretaceous. There were no unified and larger-scale accumulation centers except several small isolated accumulation centers before the Early Cretaceous. The reasons why belts of relatively thick strata were well developed in the western basin in several stages are that this area is near the west boundary of the original Ordos Basin, there was abundant sediment supply and the hydrodynamic effect was strong. Therefore, they stand for local accumulation centers. Until the Early Cretaceous, depocenters, accumulation centers and subsidence centers were superposed as an entity in the southwest part of the Ordos Basin. Up to the end of the Middle Jurassic, there still appeared a paleogeographic and paleostructural higher-in-west and lower-in-east framework in the residual basin to the west of the Yellow River. The depocenters of the Ordos Basin from the Middle–Late Triassic to the Middle Jurassic were superposed consistently. The relatively high thermal maturation of Mesozoic and Paleozoic strata in the depocenters and their neighborhood suggest active deep effects in these areas. Generally, superposition of depocenters in several periods and their consistency with high thermal evolution areas reveal the control of subsidence processes. Therefore, depocenters may represent the positions of the subsidence centers. The subsidence centers (or depocenters) are located in the south of the large-scale cratonic Ordos Basin. This is associated with flexural subsidence of the foreland, resulting from the strong convergence and orogenic activity contemporaneous with the Qinling orogeny.     

鄂尔多斯盆地中生代沉积和堆积中心迁移及其地质意义

通过对鄂尔多斯盆地中生代构造属性、原盆面貌、岩性岩相组合、物源分析和厚度分布特征等的综合研究表明,从中晚三叠世至早白垩世,盆地沉积中心由东南向北、再向西南发生逆时针迁移;在盆地西部,早白垩世沉积前没有统一或规模较大的堆积中心,仅存在孤零分布或彼此分割、规模不大的局部堆积中心。盆地西部多个时期出现的地层较厚分布区带,是该区距盆地西界较近,物源供给充足、水动力作用强所致,故代表局部堆积中心。早白垩世,沉积、堆积和沉降中心才在盆地西南部“三位一体” 叠合分布。直到中侏罗世末,在黄河之西的今盆地残留区,总体仍呈西高东低的古地理—构造格局。盆地中晚三叠世—中侏罗世各期的沉积中心在位置上大体一致,上下大部重叠;该沉积中心及近邻,古生界和中生界的热演化程度为盆地最高,显示该区深部作用较为活跃。综合分析认为,中生代各期沉积中心的叠置及其与高热演化地区的重合,反映为总体受沉降中心控制所致,可作为盆地沉降中心的代表。大型鄂尔多斯克拉通内盆地中生代各期沉积(沉降)中心在位置上偏于盆地南部,与秦岭造山带同期强烈的会聚造山活动产生的前陆挠曲沉降相关。     

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.