南海西部海域新生代构造古地理演化及其对油气勘探的意义

南海西部海域构造复杂,主要发育有北东—北东东向、北西向和近南北向3组深大断裂。其中,北西向断裂与板块汇聚、碰撞有关,多具走滑性质;北东—北东东向断裂具有与中国东部裂谷盆地相似的发育特点,呈张扭性质;近南北向断裂可能是南海在扩张活动期间于洋、陆壳过渡部位形成的走滑调节断裂,是洋盆扩张的西部边界。新生代里,南海经历了4次成盆事件与3期扩张活动,盆地经历了古新世—中始新世陆缘断陷、渐新世—早中新世扩展与中中新世以来的热沉降3个演化阶段。陆缘断陷阶段的充填系列主要是北东—北东东向与北西向的河流—冲积扇、湖泊沼泽等陆相沉积及火山岩等;盆地扩展阶段表现为中-小型断陷、断-坳陷逐渐复合与联合为大-中型坳陷,古地理格局逐渐由河流与湖沼陆相环境演变为滨海至浅海相的沉积环境;热沉降阶段的成盆活动逐渐减弱以至停止,地层表现超覆,盆地出现联合迹象。结合以往勘探与油气资源调查成果分析,认为南海西部海域陆架陆坡区发育的大-中型沉积盆地石油地质条件良好,蕴藏着丰富的油气资源,勘探潜力巨大。     

南海北部新生代海陆变迁与不同盆地的沉积充填响应*

新生代以来南中国海的多幕旋回运动形成了其北部陆坡性质各异、演化有别的多个陆缘沉积盆地。依据各盆地新生界发育特征、主干地震剖面及钻井资料对南海北部的相对海平面变化与沉积环境进行系统分析,采用年代地层对比的方法探讨南海北部构造演化序列与海陆变迁规律的内在联系,再现了南海北部陆缘新生代的海陆变迁过程,从而建立了南海北部陆缘裂谷盆地、走滑拉分盆地和陆内裂谷盆地的构造—沉积充填一体化模式。新生代海平面整体呈上升趋势,古近纪各盆地以陆相河流、粗粒三角洲湖相沉积为主;而新近纪主要发育滨浅海及三角洲相,呈现出明显的早陆后海的规律。靠近陆地一侧的陆内裂谷盆地北部湾盆地海侵最晚,其古近系充填厚度明显大于新近系,以发育近源扇三角洲为特色;而靠近海域一侧的走滑拉分盆地(莺歌海盆地)则以新近纪海相沉积占优势;陆缘裂谷盆地(琼东南与珠江口盆地)古近纪陆相与新近纪海相相对均衡发育,发育大型三角洲与碳酸盐岩台地。不同盆地的沉积充填特征主要受构造运动与海侵规模控制,并由此奠定了不同盆地的资源前景。     

中国中生代沉积盆地演化

在综合分析中生代早-中三叠世、晚三叠世-早白垩世、晚白垩世-白垩纪3个时段中国沉积盆地分布、充填序列、岩相古地理和构造古地理的基础上, 建立了中国中生代沉积盆地的时空演化, 并探讨了中国中生代沉积盆地的时空演化与中生代构造运动的响应关系, 认为: (1)随着亚洲洋俯冲消亡及天山-兴蒙造山系形成, 中国北方地区总体处于古亚洲洋消亡以后, 陆块汇聚碰撞背景, 西北地区盆山格局基本定型, 南部古特提斯洋的双向俯冲消减, 在北羌塘-三江多岛弧盆系中的一系列弧后洋盆相继俯冲消亡; (2)晚三叠世的"印支运动"使古亚洲陆最终固结并向外增生, 中国己经基本形成了南海北陆的分布格局, 绝大部分地区进入陆内演化阶段.印支期以后, 华南中部上隆, 隔开了西部的古地中海域和东部的古太平洋海域; (3)中侏罗世以来, 在古太平洋板块向欧亚大陆俯冲的影响下, 整个中国东部卷入滨太平洋构造域, 西太平洋型活动大陆边缘形成.中国东北大部分地区为弧内裂陷(火山沉积)盆地; 华北-阿拉善陆块东西分化, 中西部主要发育压陷盆地或断陷盆地或坳陷盆地, 东部则形成与古太平洋板块俯冲有关的陆缘岩浆弧弧内裂陷盆地; 华南则以雪峰山为界, 东部广泛发育与陆缘岩浆弧演化相关的弧内裂陷盆地, 西侧则发育陆内大型压陷盆地、断陷盆地或断坳盆地.中国西南则仍然为多岛洋弧盆系格局.      

试论南中国海盆地新生代板块构造及盆地动力学

南海地处欧亚、印度—澳大利亚和菲律宾海板块的交互带,是西太平洋地区面积最大的边缘海之一,其成因机制和演化过程对探讨特提斯构造域和太平洋构造域相互作用及油气勘探等问题具有重要意义,虽备受关注但仍存争议.综合目前该区及外围已有的大地构造等方面的资料,本文从探讨南海外围的构造格架及中-新生代演化过程入手,分析了南海及外围板块...     

中亚及中国西部侏罗纪沉积盆地的构造特征

侏罗纪是中亚和中国西部地区沉积盆地主要形成时期,这表现在两个方面:(1)先期存在的盆地在此阶段沉积范围持续扩大;(2)形成了许多新的侏罗纪沉积盆地.本文通过对劳亚大陆南部侏罗纪特提斯北带构造特征、诸盆地早-中侏罗世岩相古地理和构造样式的分析,表明中国西部与中亚地区在侏罗纪时虽然都处于新特提斯北部被动大陆边缘,但由于受帕米尔弧向北推挤的影响,以及昆仑构造带与塔拉斯-费尔干纳断裂和阿尔金大型走滑断裂的存在,这两个地区的侏罗纪盆地具有完全不同的构造起因.以塔拉斯-费尔干纳断裂为界,西南侧中亚地区的侏罗纪沉积盆地主要是由新特提斯北部大陆边缘的被动伸展形成;东北侧中国西部的侏罗纪沉积盆地则主要发育于区域性挤压构造背景之下,形成的主要机制是重力陷落.此外,沿塔拉斯-费尔干纳断裂还存在几个侏罗纪的走滑拉分盆地.中国西部与中亚地区侏罗纪盆地的不同成因特征对盆地的比较研究和寻找侏罗系烃源岩都具有重要意义.     

Observations on the processes of sedimentary basin formation at the margins of Southern Africa

Three variants of Atlantic-type continental margin border Southern Africa. On the west is a rifted margin with a rift phase no more than 50 m.y. in length (180–130 m.y. ago). Sedimentary basin formation was by upbuilding of a sediment terrace during the rift phase and the 30 m.y. following, with outbuilding of the terrace dominant during the Cainozoic. Little downwarping of the oceanic crust occurred but the continent—ocean transition zone appears to be wide.To the south of South Africa is an extensive sheared margin. Basin formation began here in mid-Triassic times with intermontane deposition. Local increase in lower crustal density appears to have accompanied subsidence. Truncation of the basins occurred 130–2100 m.y. ago and in places detrital influx was trapped behind a marginal fracture ridge. No continental rise sedimentary apron and characteristic deep structure were formed in these places. A ‘welding’ of the continental edge appears to have taken place.East of 30° E a complex continental margin with a protracted rift phase exists. From Triassic to Cretaceous times sedimentary basin formation was controlled by an E-W tensional stress regime resulting in N-S horsts and grabens. This was accompanied by vol-canicity and crustal thinning. Other stress systems may have prevailed during continental break-up in the Cretaceous while today the region is seismically active and the tensional stress assumed to be E-W. Following break-up sedimentary basins in Natal Valley and Mozambique Channel encroached southwards.     

Structure and tectonic evolution of the Southern Eurasia Basin, Arctic Ocean

Multichannel seismic reflection data acquired by Marine Arctic Geological Expedition (MAGE) of Murmansk, Russia in 1990 provide the first view of the geological structure of the Arctic region between 77–80°N and 115–133°E, where the Eurasia Basin of the Arctic Ocean adjoins the passive-transform continental margin of the Laptev Sea. South of 80°N, the oceanic basement of the Eurasia Basin and continental basement of the Laptev Sea outer margin are covered by 1.5 to 8 km of sediments. Two structural sequences are distinguished in the sedimentary cover within the Laptev Sea outer margin and at the continent/ocean crust transition: the lower rift sequence, including mostly Upper Cretaceous to Lower Paleocene deposits, and the upper post-rift sequence, consisting of Cenozoic sediments. In the adjoining Eurasia Basin of the Arctic Ocean, the Cenozoic post-rift sequence consists of a few sedimentary successions deposited by several submarine fans. Based on the multichannel seismic reflection data, the structural pattern was determined and an isopach map of the sedimentary cover and tectonic zoning map were constructed. A location of the continent/ocean crust transition is tentatively defined. A buried continuation of the mid-ocean Gakkel Ridge is also detected. This study suggests that south of 78.5°N there was the cessation in the tectonic activity of the Gakkel Ridge Rift from 33–30 until 3–1 Ma and there was no sea-floor spreading in the southernmost part of the Eurasia Basin during the last 30–33 m.y. South of 78.5°N all oceanic crust of the Eurasia Basin near the continental margin of the Laptev Sea was formed from 56 to 33–30 Ma.     

珠江口盆地裂后阶段性差异沉降及其成因机制*

位于南海北部陆缘的珠江口盆地裂后沉降特征不同于陆内典型断陷盆地。研究表明,盆地裂后期发生了阶段性有序差异沉降,可分为4个阶段: (1)渐新世早期(~33.9~27.2 Ma),以盆地整体缓慢沉降,大规模海侵为主要特征;(2)渐新世晚期(~27.2~23.0 Ma),以邻近西北次海盆的珠四坳陷强烈沉降为主要特征,差异沉降控制了陆架坡折带的发育和该时期陆架浅水和陆坡深水沉积环境的分布;(3)中新世早—中期(~23.0~10.0 Ma),陆缘强烈沉降区向北扩展至珠二坳陷,尤其是白云凹陷,导致陆架坡折带向北跃迁,并奠定了现今陆架浅水和陆坡深水的沉积格局;(4)中新世晚期—现今(~10.0~0 Ma),陆缘构造沉降逐渐减弱,陆坡由沉积区转变为沉积过路区,沉积物得以大量进入西北次海盆。渐新世2期快速沉降的初始时间,分别对应于南海扩张脊的跃迁,陆缘裂后沉降随扩张脊向南跃迁而向北扩展,并伴有岩浆作用的早强晚弱特点,而沉降量的大小则与裂陷期地壳的薄化程度正相关,反映了陆缘岩石圈经历了早期挠曲回弹的均衡调整和扩张脊跃迁导致地幔物质有序向南撤离而沉降的演化过程。珠江口盆地裂后有序差异沉降控制了陆架坡折带的发育,进而控制了浅水与深水两大沉积体系的展布。     

盆地演化与地球动力学旋回

盆地演化受地球演化节律所制约，节律由多层次构成。地球动力学旋回主要有３个级序：（１）超级大陆旋回，主要由羽柱构造的地幔对流动力学所控制，产生超级大陆的裂解和拼合，形成全球性同步隆升与沉降的克拉通盆地；（２）地槽旋回或造山旋回，主要由板块构造的岩石圈运动学所控制，按威尔逊旋回进展，发育各类盆地和造山带，形成“区域性”穿时开合与“非对称”互补；（３）褶皱幕或裂陷幕，主要由地体构造与拆层作用几何学所控制，产生盆地内各种构造样式和沉积样式，形成地方性的穿时递进变形，发育幕式变形和幕式沉积作用等。     

Regional tectonic framework,structure and evolution of the western marginal basins of India

The Kutch-Saurashtra, Cambay and Narmada basins are pericontinental rift basins in the western margin of the Indian craton. These basins were formed by rifting along Precambrian tectonic trends. Interplay of three major Precambrian tectonic trends of western India, Dharwar (NNW-SSE), Aravalli-Delhi (NE-SW) and Satpura (ENE-WSW), controlled the tectonic style of the basins. The geological history of the basins indicates that these basins were formed by sequential reactivation of primordial faults. The Kutch basin opened up first in the Early Jurassic (rifting was initiated in Late Triassic) along the Delhi trend followed by the Cambay basin in the Early Cretaceous along the Dharwar trend and the Narmada basin in Late Cretaceous time along the Satpura trend. The evolution of the basins took place in four stages. These stages are synchronous with the important events in the evolution of the Indian sub-continent—its breakup from Gondwanaland in the Late Triassic-Early Jurassic, its northward drifting during the Jurassic-Cretaceous and collision with the Asian continent in the Early Tertiary. The most important tectonic events occurred in Late Cretaceous time. The present style of the continental margins of India evolved during Early Tertiary time.The Saurashtra arch, the extension of the Aravalli Range across the western continental shelf, subsided along the eastern margin fault of the Cambay basin during the Early Cretaceous. It formed an extensive depositional platform continuous with the Kutch shelf, for the accumulation of thick deltaic sediments. A part of the Saurashtra arch was uplifted as a horst during the main tectonic phase in the Late Cretaceous.The present high thermal regime of the Cambay-Bombay High region is suggestive of a renewed rifting phase.     

Geological framework of the Brazilian continental margin

Based on distinctive stratigraphic and/or structural characteristics, the Brazilian continental margin can be divided into two main provinces:

1. The southeastern-eastern province, extending from the Pelotas to the Recife-João Pessoa Basin, presents a tensional tectonic style of Late Jurassic-Early Cretaceous age, paralleling the structural alignements of the Precambrian basement, except in the north-eastern segment where the Mesozoic faults of the Recife-João Pessoa Basin cut across the east-west basement directions. The basin-fill, Upper Jurassic through Recent, consists, where complete, of three stratigraphic sequences, each of a distinct depositional environment: (a) a lower clastic non-marine sequence; (b) a middle evaporitic sequence, and (c) an upper clastic paralic and open marine sequence.
2. The northern province, extending from the Potiguar Basin to the Amazon Submarine Basin, displays both tensional and compressional tectonic styles of Upper Jurassic (?) to Upper Cretaceous age either paralleling or cutting transversally the basement alignments. The stratigraphic column differs from the southeastern-eastern province in lacking the Lower Cretaceous evaporitic rocks.

The integration of the stratigraphie and structural data allows one to determine in the eastern Brazilian marginal basins the main evolutionary stages of a typical pull-apart continental margin: a continental pre-rift and rift stage, an evaporitic proto-ocean stage, and a normal marine open ocean stage. In the northern province it is possible to infer a continental rift-valley-stage, a transform stage and an open continental-margin stage. The relationship between the rift-valley and the transform stages is yet not clear.     

中国东部新生代沉积盆地演化

新生代, 中国东部大陆边缘系统总体受到来自印度、澳大利亚、菲律宾和太平洋板块向欧亚板块下部俯冲碰撞的作用, 在大陆边缘形成一系列边缘海盆地和断陷-坳陷盆地, 主要发育松辽、渤海湾、江汉、苏北、东海、珠江口和北部湾等盆地.基于中国东部沉积盆地的中生代构造背景分析和新生代盆地的分布特征, 对其中的7个主要沉积盆地进行了详细的沉积序列和构造演化分析.通过周缘板块和郯庐断裂的构造演化、火山活动、低温热年代学、气候演变等对比分析, 中国东部沉积盆地的演化可划分为3个阶段: 古新世-始新世、渐新世-早中新世和晚中新世-第四纪.      

构造事件的沉积响应—建立青藏高原大陆碰撞、隆升过程时空坐标的设想和方法

沉积盆地的地层形态、岩相类型以及空间配置样式是构造事件的重要标识.沉积序列中特征岩石组分的出现标志着毗邻造山带隆升的初始启动时间,与物源区地层单元垂向叠置序列相反或相同的岩屑组分剖面分布则是幕式构造旋回的反映.在前陆盆地中砾石层的出现被认为是冲断岩席活动的记录,而在断陷盆地和走滑拉分盆地中通常可识别出100m级的向上变粗和向上变细的旋回层,它们被解释为构造高地重复隆升和溯源侵蚀的结果.最近的研究工作表明,急剧的构造沉降主要是通过细粒级河湖相沉积补偿的,广泛的砾岩进积发生在构造活动的平静期.构造驱动的山脉隆升表现为砾岩地层呈楔状体,纵向河流水系发育;重力均衡回返所导致的山系隆升则形成以横向河流水系为主的板状砾岩沉积.从青藏高原腹地、周缘和外延海洋盆地的沉积记录中可获取重大构造变革时期的信息,也许是解决目前有关印度与亚洲大陆碰撞、高原隆升等时性或穿时性以及限定陆内变形调节机制的一个重要手段.     

构造事件的沉积响应——建立青藏高原大陆碰撞、隆升过程时空坐标的设想和方法

沉积盆地的地层形态、岩相类型以及空间配置样式是构造事件的重要标识，沉积序列中特征岩石组分的出现标志着毗邻造山带隆升的初始启动时间，与物源区地层单元垂向叠置序列相反或相同的岩屑组分剖面分布则是幕式构造旋回的反映，在前陆盆地中砾石层的出现被认为是冲断岩席活动的记录，而在断陷盆地和走滑拉分盆地中通常可识别出100m级的向上变粗和向上变细的旋回层，它们被解释为构造高地重复姓升和溯源侵蚀的结果，最近的研究工作表明，急剧的构造沉降主要是通过细粒级河湖相沉积补偿的，广泛的砾岩进积发生在构造活动的平静期，构造驱动的山脉隆升表现为砾岩地层呈楔状体，纵向河流水系发育；重力均衡回返所导致的山系隆升则形成以横向河流水系为主的板状砾岩沉积，从青藏高原腹地、周缘和外延海洋盆地的沉积记录中可获得取重大构造变革时期的信息，也许是解决目前有关印度与亚洲大陆碰撞、高原隆升等时性或穿时性以及限定陆内变形调节机制的一个重要手段。     

尼泊尔及南侧邻区元古宙以来的构造-沉积演化

迄今,尼泊尔及其南侧邻区元古宙以来的构造-沉积演化尚缺乏系统性研究.为了促进区域地质认识,结合前人研究成果及新的研究发现,对尼泊尔低喜马拉雅带及以南的构造-沉积演化首次进行系统性总结与讨论.结果表明:尼泊尔低喜马拉雅带及以南与印度地盾北缘在地质历史中的构造-沉积演化息息相关,且自元古宙以来,发育了被动大陆边缘→陆内裂谷→被动大陆边缘→前陆盆地等不同构造演化阶段的沉积响应;尼泊尔西部的Dailekh群属于~1.8 Ga以前或前哥伦比亚超大陆之前的被动大陆边缘沉积;Vindhyan超群为下断上坳的陆内裂谷沉积,尼泊尔境内的Lakharpata群相当于下Vindhyan群;Gondwana超大陆裂解导致由北往南形成一系列初始发育时间越来越晚的裂谷盆地;Surkhet群至Siwalik群为被动大陆边缘至前陆盆地沉积,其中,Surkhet群Swat/Subathu组是喜马拉雅南侧地质历史上最后一套海相沉积地层,也是被动大陆边缘向前陆盆地转换期的沉积响应;Siwalik群大规模的磨拉石建造标志着喜马拉雅快速和大幅度隆升,该群沉积成岩后,印度-欧亚板块进一步的挤压作用导致了地质历史上迄今为止最后一次强烈的构造运动,形成MFT与Siwalik褶皱带,并奠定了喜马拉雅带现今构造格局.      

Petroleum Geology in Deepwater Settings in a Passive Continental Margin of a Marginal Sea: A Case Study from the South China Sea

Deepwater oil and gas exploration has become a global hotspot in recent years and the study of the deep waters of marginal seas is an important frontier research area.The South China Sea(SCS)is a typical marginal sea that includes Paleo SCS and New SCS tectonic cycles.The latter includes continental marginal rifting,intercontinental oceanic expansion and oceanic shrinking,which controlled the evolution of basins,and the generation,migration and accumulation of hydrocarbons in the deepwater basins on the continental margin of the northern SCS.In the Paleogene,the basins rifted along the margin of the continent and were filled mainly with sediments in marine-continental transitional environments.In the Neogene–Quaternary,due to thermal subsidence,neritic-abyssal facies sediments from the passive continental margin of the SCS mainly filled the basins.The source rocks include mainly Oligocene coal-bearing deltaic and marine mudstones,which were heated by multiple events with high geothermal temperature and terrestrial heat flow,resulting in the generation of gas and oil.The faults,diapirs and sandstones controlled the migration of hydrocarbons that accumulated principally in a large canyon channel,a continental deepwater fan,and a shelf-margin delta.     

秦岭早古生代沉积作用与构造演化

根据对秦岭及其两侧地台区沉积体系与旋回沉积的分析，认为该区在早古生代总体上处于板块的扩张阶段，其中巨厚的台地碳酸盐岩的广布的远洋沉积是其典型岩相。早奥陶世阿伦尼克中期华北地台南的一度隆升与剥蚀，标志着俯冲作用开始，但未发现加里东期碰撞造山作用的证据。该区晚奥陶世一志留纪大规模的海退主要是全球海平面下降的结果，与碰撞造山人关系不大。     

Qinling Orogenic Belt: Its Palaeozoic-Mesozoic Evolution and Metallogenesis

The formation, development and evolution of the Qinling erogenic belt can be divided into three stages: (1) formation and development of Precambrian basement in the Late Archaean-Palaeoproterozoic (3.0-1.6 Ga), (2) plate evolution (0.8-0.2 Ga), and (3) intracontinental orogeny and tectonic evolution in the Mesozoic.The Devonian (D) and Triassic (T) were the key transition period of the tectonic evolution of the Qinling orogenic belt. That is to say, in the Devonian, the Qinling micro-plate was separated from the northern margin of the Yangtze plate (passive continental margin). This period witnessed transition of the micro-plate from the compressional to ex-tensional state, and consequently three types of sedimentary basins were formed, namely, the rift hydrothermal basin in the micro-plate, restricted ocean basin in the south, and residual ocean basin resulting from collision on the northern margin. In the Triassic the Qinling area was turned into the intracontinental orogen.The Devonian and Triassic w     

白云鄂博地区构造格局与古板块构造演化

通过对白云鄂博及周边地区地质和构造形迹的系统调研,综合分析了白云鄂博地区的古板块构造单元、白云鄂博群的沉积构造背景以及白云鄂博地区的构造组合特征。白云鄂博群可以划分为三个沉积组合,它们分别代表中元古代、晚元古代和早古生代白云鄂博地区由陆内裂谷向陆缘裂谷转化到活动大陆边缘裂谷的沉积过程。白云鄂博地区以白银角拉克－宽沟断裂为界,南北两侧存在重大地质差异。断裂南侧的该群岩石不整合覆盖在相当于五台群的巴尔腾山群之上,是在华北陆壳基底上发展起来的陆缘沉积。局部碳酸盐岩和页岩层位在加里东期遭受了强烈的地幔流体改造,形成大规模稀土矿化;在海西期又遭受了强烈的区域变质改造。断裂北侧的白云鄂博群以发育蛇绿混杂岩－叠瓦状况断层－紧闭同斜褶皱为特征,具有古板块俯冲形成的加积杂岩特征。在此基础上,对白云鄂博地区的古板块构造演化动力学过程进行了初步总结。