北部湾盆地北部坳陷构造——沉积特征及其演化

在二维和三维地震资料解释基础上,对北部湾盆地北部坳陷地层分布及断裂系统进行了研究,建立了坳陷断裂分布格局及构造样式;结合地层和钻井资料分析了断裂活动期次和特征,揭示古近纪坳陷构造演化经历了三期幕式断陷活动：古新世,初期拉张裂陷阶段,形成狭小的半地堑;始新世早中期,第二期强烈拉张裂陷阶段,形成统一的湖盆,发育两个沉积中心;渐新世,断坳转换期,涠西南低凸起和3号断裂强烈活动,沉积中心迁移至海中凹陷.这为进一步油气勘探工作提供了有价值的参考.     

琉球沟弧盆系莫氏面深度的三维广义反演

本文利用三维广义反演技术对重力资料进行反演，计算出了琉球沟弧盆系地区的莫氏面深度。由于考虑了分辨率和方差之间的最佳折衷问题，反演结果不论是在精度上还是在分辨能力方面都有了明显改进。分析结果也表明，重力反演得到的莫氏面深度同李昭兴等人用地震折射波法得到的莫氏面深度有较大的差别。文中地产生这种差别的可能原因提出了自己的见解。     

太阳盆地中新生代断裂特征及成因机制

太阳盆地位于北黄海盆地的东部,是一个发育在中-朝克拉通基底之上的中、新生代沉积盆地,勘探程度非常低。最新二维地震资料揭示,太阳盆地的断裂体系可以分控盆断裂、控凹(坳)断裂、控带断裂、控圈断裂和分割性断裂。盆地发育以NE向和NW向为主的的正断层和逆断层,而少量断层呈近EW或SN向。对不同类型的断裂构造特征及样式分析表明,断裂的活动期次可分为4期:晚侏罗世—早白垩世伸展断层、晚白垩世逆冲断层、始新世伸展正断层和新近纪正断层。中、新生代以来,中国东部构造演化主要受其东部太平洋板块活动控制,晚侏罗纪开始,洋壳俯冲在东部的欧亚大陆之下,伴随着太平洋—菲律宾板块的俯冲,太阳盆地发生NNE—SSW向的拉张;晚白垩世时期,由于太平洋板块俯冲方向的改变,区域性拉张变为区域性NNW—SSE向挤压,太阳盆地的一系列NW向逆断层形成;在始新世—渐新世,太平洋板块向东亚大陆作斜向减速俯冲,导致太阳盆地遭受NWW—SEE向拉张作用,再次断陷;渐新世末期,受喜山运动第Ⅱ幕的影响,太阳盆地发生再次的构造反转,形成一系列的小规模断层。     

南沙海域万安盆地地质构造特征

利用在南沙海域万安盆地所采集的地震、重磁资料及钻井、地质资料，对该盆地的地震反向特征，沉积特征、区域地质、构造特征及构造发展史进行了的简要的论述，本文以该区Ｔｇ深度资料为基础，并利用ＣＣＯＰ年刊发表的新生代基底深度资料，初步圈定了万安盆地的边界，并对盆地二级构造单元进行了划分，将盆地划分为５坳３隆、坳隆相间的构造格局。     

东非鲁伍马盆地深水沉积体系及油气勘探意义

利用高分辨率三维地震资料、测井和钻井数据,对东非鲁伍马盆地深水沉积特征进行了系统刻画。根据深水沉积体的地震相特征,识别出峡谷、水道、漫溢沉积、朵体、块体搬运沉积(MTDs)和凝缩段等深水沉积单元,建立了地震识别图版。分析总结了水道和朵体的岩性特征、电性特征和储层物性特征,砂岩具有低伽马(GR)和高电阻(RT)特征,厚层砂岩GR曲线呈“箱型”,有泥岩夹层的砂岩段呈叠加的“钟型”特点;储层压实程度弱,发育原生粒间孔隙,具有中—高孔、中—高渗的特征。结合成藏条件研究,认为由水道和朵体浊积砂岩储层、凝缩段和漫溢沉积泥岩盖层、天然堤和MTDs为侧向遮挡等要素构成的油气储、盖配置关系,是研究区油气成藏的一个关键因素,对深水油气勘探具有一定的指导意义。     

西地中海的弧后盆地

地中海是太平洋之外弧后盆地较为发育的海区。巴利阿里海盆和第勒尼安海盆是西地中海两个位置相邻、互有成因联系的弧后盆地。海盆莫霍面埋深分别为 1 2～ 1 5km和 1 0 km,热流密度分别为 1 0 0 m W/m2和 2 0 0 m W/m2 ,发育有大洋型磁条带异常 ,大洋钻探和拖网取样均采到了拉斑玄武岩。较之巴利阿里海盆 ,第勒尼安海盆更富年青性。两弧后盆地的成生演化是与欧洲板块与非洲 -阿普利亚板块的相互作用息息相关的。中新世 ,随着非洲 -阿普利亚板块向西、西北俯冲 ,科西嘉、撒丁裂离欧洲大陆 ,巴利阿里海盆被打开 ;上新世 ,阿普利亚微板块进一步俯冲 ,导致亚平宁与科西嘉、撒丁之间的裂离 ,形成第勒尼安海盆。     

北部湾盆地北部坳陷古近纪原型结构分析

北部湾盆地北部坳陷古近纪受多期次构造运动的影响,后期改造强烈.从现今构造格局出发,通过剥蚀量恢复并结合断裂活动特征,进行了北部湾盆地北部坳陷古近纪原型结构重建及成凹机制探讨.认为北部湾盆地北部坳陷古近系沉积沉降中心在时空上呈现由西向东和由北向南的迁移特征;始新世流沙港组沉积时期涠西南凹陷D次凹与海中凹陷的西洼为同一沉积单元;断裂和隆起联合控制了洼陷的基本形态,特别是涠西南低凸起的活动对北部坳陷古近纪统一湖盆的分割起关键作用.     

日本海地质构造特征

本文主要根据地质，地震，磁力，地热，重力等资料，分析了日本海的地质构造特征。日本海是一个广阔的边缘海，四周被大陆架所围。自东北至西南依次为日本，海盆，大和海脊，大和盆地及马海贫。大和海脊由陆壳物质组成，盆地中心则以洋壳为底。热流值高而变率小，说明日本海是一个成熟的弧后盆地，扩张停止于中新世。日本海在更新世最低海面时，与大洋交换断绝，沉积物中含碳比较丰富，这是一个罕见的特征。     

沙捞越盆地的盆地类型分析

针对沙捞越盆地盆地类型的不同观点,通过盆地区域构造背景、构造演化阶段、构造沉降曲线的分析以及构造地质事件的恢复,得到以下认识:①盆地的构造演化可划分为晚白垩世—晚始新世,拉让洋壳向婆罗洲基底俯冲,并在婆罗洲中部形成火山岛弧的俯冲增生期;渐新世—早中新世,拉让洋壳俯冲消减完毕,路科尼亚地块与婆罗洲碰撞,并俯冲于婆罗洲基底之下,形成周缘前陆盆地的前陆盆地期;中中新世至今,南中国海开启、婆罗洲碰撞抬升引起盆地稳定沉降的被动边缘期3个阶段。②盆地所选井的构造沉降曲线具有早期缓慢沉降、晚期快速沉降这一前陆盆地的典型特征。③盆地构造地质事件复原图表明,盆地晚期处于被动大陆边缘构造背景。由此,认为沙捞越盆地为复合型盆地,即早期为前陆盆地,晚期则转化为大陆边缘型盆地。     

北黄海盆地与朝鲜安州盆地和中国胶莱盆地的对比

北黄海盆地位于黄海北部,是我国油气地质与勘探开发研究相对最为薄弱的海域,在研究的3个盆地中,北黄海盆地系海域含油气盆地,面积5万km^2,迄今我国尚未钻井;朝鲜安州盆地系跨海陆域盆地,面积最小,但是钻井最多;中国胶莱盆地则为最邻近北黄海盆地的陆域沉积盆地,目前有少量钻井,并是胜利油田外围勘探盆地。在前人研究基础上,利用后两者钻井地质与野外剖面调查的测试研究成果,初步对比了3个沉积盆地地层岩性沉积与含油气性的特征。     

Structure and evolution of a passive margin in a compressive environment: Example of the south-western Alps-Ligurian basin junction during the Cenozoic

We focus on the northern Ligurian margin, at the geological junction of the subalpine domain and the Ligurian oceanic basin, in order (1) to identify the location of the southern limit of the Alpine compressive domain during the Cenozoic, and (2) to study the influence of a compressive environment on the tectonic and sedimentary evolution of a passive margin.Based on published onshore and offshore data, we first propose a chronology of the main extensional and compressional regional tectonic events.High-resolution seismic data image the margin structure down to ∼3 km below seafloor. These data support that past rifting processes control the present-day margin structure, and that 2800-4000 m of synrift sediment was deposited on this segment of the margin in two steps. First, sub-parallel reflectors indicate sediment deposition within a subsident basin showing a low amount of extension. Then, a fan-shaped sequence indicates block tilting and a higher amount of extension. We do not show any influence of the Miocene Alpine compression on the present-day margin structure at our scale of investigation, despite the southern subalpine relief formed in the close hinterland at that time. The southern front of the Miocene Alps was thus located upslope from the continental margin.Finally, a comparison with the Gulf of Lions margin suggests that the tectonic influence of the Alpine compression on the rifting processes is restrited to an increase of the subsidence related to flexure ahead of the Alpine front, explaining abnormally high synrift thicknesses in the study area. The Alpine environment, however, has probably controlled the sedimentary evolution of the margin since the rifting. Indeed, sediment supply and distribution would be mainly controlled by the permanent building of relief in the hinterland and by the steep basin morphology, rather than by sea-level fluctuations, even during the Messinian sea-level low-stand.     

Regional structure and tectonic history of the obliquely colliding Columbus foreland basin, offshore Trinidad and Venezuela

Cenozoic eastward migration of the Caribbean plate relative to the South American plate is recorded by an 1100-km-long Venezuela-Trinidad foreland basin which is oldest in western Venezuela (65-55 Ma), of intermediate age in eastern Venezuela (34-20 Ma) and youngest beneath the shelf and slope area of eastern offshore Trinidad (submarine Columbus basin, 15.0 Ma-Recent). In this study of the regional structure, fault families, and chronology of faulting and tectonic events affecting the hydrocarbon-rich Columbus foreland basin of eastern offshore Trinidad, we have integrated approximately 775 km of deep-penetration 2D seismic lines acquired by the 2004 Broadband Ocean-Land Investigations of Venezuela and the Antilles arc Region (BOLIVAR) survey, 325 km of vintage GULFREX seismic data collected by Gulf Oil Company in 1974, and published industry well data that can be tied to some of the seismic reflection lines. Top Cretaceous depth structure maps in the Columbus basin made from integration of all available seismic and well data define for the first time the elongate subsurface geometry of the 11-15 km thick and highly asymmetrical middle Miocene-Recent depocenter of the Columbus basin. The main depocenter located 150-200 km east of Trinidad and now the object of deepwater hydrocarbon exploration is completely filled by shelf and deepwater sediments derived mainly from the Orinoco delta. The submarine Darien ridge exhibits moderate (20-140 m) seafloor relief, forms the steep (12°-24°), northern structural boundary of the Columbus basin, and is known from industry wells to be composed of 0.5-4.5 km thick, folded and thrust-imbricated, hydrocarbon-bearing section of Cretaceous and early Tertiary limestones and clastic rocks. The eastern and southern boundaries of the basin are formed by the gently (1.7°-4.5°), northward-dipping Cretaceous-Paleogene passive margin of South America that is in turn underlain by Precambrian rocks of the Guyana shield.Interpretation of seismic sections tied to wells reveals the following fault chronology: (1) middle Miocene thrusting along the Darien ridge related to highly oblique convergence between the Caribbean plate and the passive margin of northern South America; continuing thrusting and transpression in an oblique foreland basin setting through the early Pleistocene; (2) early Pliocene-recent low-angle normal faults along the top of the Cretaceous passive margin; these faults were triggered by oversteepening related to formation of the downdip, structurally and bathymetrically deeper, and more seaward Columbus basin; large transfer faults with dominantly strike-slip displacements connect gravity-driven normal faults that cluster near the modern shelf-slope break and trend in the downslope direction; to the south no normal faults are present because the top Cretaceous horizon has not been oversteepened as it is adjacent to the foreland basin; (3) early Pliocene-Recent strike-slip faults parallel the trend of the Darien ridge and accommodate present-day plate motions.     

黄海三大盆地的构造演化

７０年代末到８０年代中期，中国地质矿产部和中国科学院所属单位对黄海进行了大量地球物理调查和钻探，根据多道反射地震资料，浅地层剖面，重磁资料和钻探结果对黄海三大构造盆地进行地质构造学分析研究，结果表明，黄海地区三大盆地自北往南形成时代逐渐变新，构造活动性逐渐增强。     

南黄海盆地构造特征及油气地质意义

南黄海盆地发育于前南华纪变质基底之上,是一个大型叠合盆地,经历了多期成盆和多期构造改造,形成了海相盆地和中新生代断陷盆地叠合改造型残留盆地。盆地演化历经南华纪—早、中三叠世海相地层发育期、晚白垩世—古近纪箕状断陷发育期和新近纪—第四纪坳陷发育期,为一典型地台—断陷—坳陷多层结构的复合型盆地。通过对地震资料解释、区域地质构造特征分析,综合烃源条件和后期保存条件,探讨了南黄海盆地油气远景。     

Structural controls on Quaternary deepwater sedimentation, mud diapirism, and hydrocarbon distribution within the actively evolving Columbus foreland basin, eastern offshore Trinidad

Eastward migration of the Caribbean plate relative to the South American plate has caused lithospheric loading along the northern margin of South America, which is recorded by an 1100-km-long foreland basin which is oldest in the west (Maracaibo basin, 65-55 Ma) and youngest in the east (Columbus basin, eastern offshore Trinidad, 15-0 Ma). The Orinoco River has been the primary source of sediment for the basin since early Miocene. We have integrated approximately 775 km of deep-penetration 2D seismic lines acquired in the area of eastern offshore Trinidad as part of the 2004 “Broadband Ocean-Land Investigations of Venezuela and the Antilles arc Region” (BOLIVAR) project, 8000 km² of shallow industry 3D seismic data, and published industry well data from offshore eastern Trinidad. Active mud diapirism in the Columbus basin is widespread and is related to overthrusting and tectono-sedimentary loading of upper Miocene-lower Pliocene age mud. Analysis of the shallow 3D seismic data reveals the presence of extensive gravity-flow depositional elements on the Columbus basin slope and the deepwater area. These stacked gravity-flow deposits are characterized by mass-transport deposits at the base, turbidite frontal-splay deposits, leveed-channel deposits, and capped by fine-grained condensed-section deposits. Exploration targets in the deepwater area are located towards the center of the Columbus basin, where northeast-trending fault-propagation folds are important Plio-Pleistocene trap-forming elements. Deep basin wells drilled in recent years have proven that turbidites were transported into the deepwater Columbus basin during the Plio-Pleistocene. Analysis of these well results suggests that a deeper oil charge is present within the deepwater Columbus basin area. The primary uncertainty for this variable hydrocarbon system is whether fault or diapiric pathways connect or divert the petroleum charge at depth with shallower reservoir rocks.     

Tectonostratigraphic evolution of the Morichito piggyback basin, Eastern Venezuelan Basin

The Morichito piggyback basin (MPB) is a SW-NE-oriented depocenter in the Eastern Venezuelan Foreland Basin (EVFB). This piggyback basin formed by overlying the Pirital thrust during the middle to late Miocene as a result of oblique collision between the Caribbean and South-American Plates. The MPB covers an area encompassing approximately 1000 km² between the Serrania del Interior range and the Pirital high, which is a hanging wall uplift along the Pirital thrust that acts as a confining barrier on the southern boundary of the MPB. Previous studies have tried to address the tectonostratigraphic significance of the MPB, but new biostratigraphic information and recently acquired 3D seismic data have allowed us to expand the understanding of this basin. The MPB occupies a relatively small area of the EVFB; however, the MPB contains a valuable stratigraphic record that can be used to unveil the timing of the main deformational events that took place in the EVFB.This work presents the tectonostratigraphic evolution of the MPB by defining four tectonostratigraphic sequences (T1-T4). Each sequence was defined on the basis of integration of well logs, biostratigraphy, and seismic geomorphological interpretations. T1 (24-16 Ma) (late Oligocene to middle Miocene), which was deposited in shallow-marine environments, extends to the south of the Pirital high beyond the boundaries of the MPB. T1 is equivalent to the early foredeep stage of the EVFB, having been formed when structural deformation and uplifting were already occurring to the north on the proto-Serrania del Interior range (∼24-16 Ma) and the Pirital thrust was active (∼22 Ma). T2 (16-11 Ma) (middle to late Miocene) is composed of alluvial-fan deposits derived from the proto-Serrania del Interior range. The geometry and internal configuration of T2 indicate that during this time the basin was transitioning from an open-foreland basin to a confined piggyback basin. During deposition of T2, the Pirital fault was active as an out-of-sequence thrusting event (16-∼11 ma). T3 (late Miocene) and T4 (early Pliocene to Recent), composed of shallow-marine and fluvial deposits, were deposited in an already restricted piggyback basin. The Pirital high was already in place during deposition of T3 (∼11-9.3 ma). T3 and T4 represent the final phases of MPB infilling, when tectonic activity and subsidence were at their lowest rates. MPB sedimentary infilling dates the activity of thrusting events in the proto-Serrania del Interior (∼24-16 Ma), timing of maximum deformation associated with the Pirital out-of-sequence thrusting event (16-∼11 Ma), timing of final emplacement of the Pirital high (∼11-9.3 Ma), and the beginning of tectonic quiescence (<5.2 Ma).     

海平面变化对太湖流域排涝的影响

太湖流域位于长江三角洲地区,其排涝过程受长江口海平面变化及潮位变化的控制。本文采用一维河网非恒定流理论,建立了太湖流域河网水文模型,并对1991年太湖流域洪涝过程进行的模拟。在此基础上,假定当太湖流域发生1991年特大暴雨过程时,海平面上升0.5m和长江口发生了百年一遇高潮位,太湖最高水位可分别达到5.01m和4.99m,整个梅雨期排涝量分别比1991年少排14.9×10⁸m³和13.1×10⁸m³,加剧了该地区洪涝灾害的严峻程度。     

南海中央海盆岩石圈纵向演化模拟

基于南海海盆的地质构造历史、地球物理和构造应力场资料建立准三维有限元模型,对南海中央海盆进行岩石圈纵向演化动力学模拟.本文采用弹塑性各向同性连续岩石介质模型,充分考虑拉伸速率、拉伸位移以及模型参数对模拟结果的影响,共建立了3个模型进行比较.从数值模拟结果可以看出中央海盆在被动拉张的地质构造背景下是单向生长的,动态模拟出南海中央海盆在形成过程中的陆缘裂离、海底扩张两个阶段的岩石圈纵向演化过程,并且分析了两个阶段岩石圈的动力学性质.提出水平的被动拉张力是南海岩石圈纵向演化前两个阶段形成的主要因素,并且在这两个阶段中,岩石圈的纵向演化时间主要集中在海底扩张阶段.     

南沙海域中建南盆地的磁性基底及地壳结构

通过对南沙海域中建南盆地重磁资料的分析及反演计算,依据盆地的地质与地球物理特征,对地震资料难以解决的基底结构、性质进行了研究,确定了磁性基底与莫霍面深度,确定了地壳类型,并对盆地内的深部大断裂及磁性基岩属性作了推断,为今后的研究提供了依据。