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西沙海槽盆地是南海北部陆坡西段的一个勘探程度较低的大型新生代深水沉积盆地。基于新采集的高精度多道地震资料并结合周边地区地质特征对盆地进行了层序地层分析,在研究区内识别出8个地震反射界面,结合地震剖面振幅旋回性变化,将研究区新生代地层划分了3个超层序和8个层序,并进一步论述了各层序的顶底接触关系、地震反射特征、地层厚度、层速度及砂岩含量等。在层序格架内识别出5类典型的地震相:平行-亚平行相、楔状发散相、前积相、杂乱相及水道充填相。在地震相划分和沉积相分析的基础上,通过对各层序沉积特征和沉积发育史的分析,认为始新世研究区呈现出陆相湖盆沉积体系特征;渐新世,盆地遭受海侵,研究区接受滨海相和浅海相沉积;早中新世,盆地中部沉积大规模半深海相沉积;中中新世末海平面出现下降,陆坡半深海环境的范围有所减小,西沙海槽浊积水道的雏形形成;晚中新世之后,研究区进入稳定的区域沉降阶段,主要发育了一套半深海-深海相泥岩沉积。此外,由研究区南北缘隆起区提供物源在层序内部还发育有近岸水下扇、三角洲、扇三角洲等沉积体,由地形高差控制作用在陡坡带或断层下降盘还形成了斜坡扇、浊积体。 相似文献
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南海东北部深部构造与中新生代沉积盆地 总被引：9，自引：1，他引：9
利用OBS资料作约束条件对南海东北部的地球物理资料，主要是重力资料和多道反射地震资料进行反演，获取比较理想的莫霍面深度，地壳厚度，中生代沉积基底面，新生代沉积底界面等地壳结构信息，研究发现该区中生代沉积盆地形成模式与新生代沉积盆地的形成模式不同，中生代沉积基底与莫霍面呈正相关，而新生代沉积基底则与莫霍面呈明显的镜像关系。中生仝层不受边界断层控制，中生代沉积基底与莫霍面呈正相关，而新生代沉积基底则与莫霍面呈明显的镜像关系。中生代地层不受边界断层控制。中生代沉积坳陷边界实质上是残留的中生代地层的边界，中生代沉积盆地具有大型坳陷沉积特征，而新生代盆地为断陷盆地。 相似文献
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陈玲 《海洋地质与第四纪地质》2008,28(5)
中建南盆地是位于南海西部陆缘的大型新生代沉积盆地。调查资料表明,盆地面积超过11×104km2,沉积厚度达8500m,局部构造发育,油气前景良好。在对盆地大量多道地震资料综合分析解释的基础上,研究了盆地局部构造的圈闭类型、分布特征和发育史。盆地的局部构造主要分为构造圈闭、地层圈闭和复合型圈闭。早期发育伸展构造样式,伴生以张性为主的局部构造圈闭;晚期受走滑应力的改造,发育花状张扭或压扭性构造;特定的构造和沉积环境则造就了地层和复合型圈闭构造。 相似文献
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西沙海槽盆地处于南海北部陆坡洋陆壳过渡带,为一个分割南海北部陆架和西沙地块的新生代裂谷盆地,其沉积环境演化研究有助于进一步认识南海形成演化过程。通过南海陆坡区域地震地层对比,将西沙海槽盆地新生代以来划分出9个地层单元,采用地震线描和地震相分析方法,恢复各地层单元沉积时期的地层结构及古地貌,探讨其沉积环境演化过程。结果表明,古新世—始新世西沙海槽盆地为河流和湖泊沉积环境;渐新世—早中新世初,演变为分割南海北部陆架和西沙地块古陆、贯通琼东南盆地和西北次盆的海峡,沉积环境由滨-浅海过渡到半深海环境;中中新世以来盆地进入陆坡海槽发育阶段,晚中新世以后中央水道形成,演变为一个陆坡内深水海槽,为海流和浊流通道,整体处于半深海-深海沉积环境。 相似文献
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南沙海域礼乐盆地中生界油气资源潜力 总被引：4，自引：0，他引：4
位于南沙东部海域的礼乐盆地是一大型的中、新生代叠置盆地,其特有的地质背景及巨厚的中生代地层显示了其与南沙海域其他新生代沉积盆地的差异。盆地内发育的厚度超过4 000 m的中生代海相地层,主要包括了上侏罗统—下白垩统的滨—浅海相含煤碎屑岩或半深海相页岩、上三叠统—下侏罗统三角洲—浅海相砂泥岩和中三叠统深海硅质页岩等3套地层,展示出盆地具有良好的油气生成潜力。而早期位于华南陆缘、现今位于南沙东部海域的礼乐盆地中生界,完全具备了形成油气藏的基本石油地质条件,具有较为良好的油气资源潜力,其中生界油气资源勘探具有非常重要的意义,将成为我国海域油气勘探的一个重要新领域。 相似文献
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北康盆地构造特征及其构造区划 总被引：3，自引：0，他引：3
北康盆地是位于南沙中部海城的新生代沉积盆地，新生代沉积盖层在盆地内广泛发育，根据地震反射特征及地震反射界面的区域对比，盆地基层可进一步划分为3个构造层。北康盆地西南边界发育延贾断裂，该断裂西起万安盆地，向东直于加里曼丹。从渐新世始，廷贾断裂先后经历了3次规模较大的构造活动。南沙海槽西北缘断裂位于北康盆地的东南边界，该断裂把北康盆地和南沙海槽盆地分隔开来。北康盆地内断裂主要有北东、北西和南北向三组，其中南北、北西向断层往往错断北东向断层。在详细讨论断层特征和沉积盖层布规律的基础上，对北康盆地的二级构造单元进行了划分。 相似文献
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南海西南部新生代盆地类型及演化历史 总被引：4，自引：0，他引：4
南海西南部地区发育了多种类型的新生代沉积盆地，各种类型的盆地具有各自的结构特征和演化历史，走滑－周缘前陆盆地－曾母盆地发育了渐新－中中新统层系，晚中新统层系和上新－第四系层系第三套地层，曾母盆地经历了三个发育阶段，拉张剪切盆地－万安盆地发育下第三系－下渐新统层系，上渐新统一中中新统层系和上中新统一第四系层系三套地层，万安盆地经历了四个发育阶段。 相似文献
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南海东北部中生代海相地层的分布及其地质地球物理特征 总被引：1，自引：0，他引：1
南海东北部的珠江口盆地珠一坳陷、东沙隆起、潮汕坳陷和台西南盆地等4个地质构造单元中,除发育巨厚新生代地层外,还发育并保留较厚的早白垩世和早侏罗世海相地层.这些地层的地震反射特征表现为大角度倾斜、可连续追踪和中低频的反射层序.由叠加速度推算的层速度为4.3-5.0km·s-1.这些中生代地层具坳陷型沉积特征而与新生代断陷型充填式沉积明显不同,残存厚度约4 000-5 000m.东沙-澎湖-北港隆起带是中生代华南地块与南海地块的缝合拼接带.该拼接带显示为地壳增厚和高磁异常,古特提斯在此消亡. 相似文献
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南海西沙海槽盆地地质构造特征 总被引：2，自引：0，他引：2
西沙海槽盆地是一个发育在南海北部陆坡深水区的新生代沉积盆地,接受了厚1 500～8 000m的沉积,沉积层中部厚,南北薄,呈南北分带特征。地震剖面上表现出下断上拗的特点,盆地裂陷期的构造样式以"多米诺式半地堑"或"地堑"为特征,控制半地堑发育的主要断层有F1、F2、F3、F4、F5。盆地发育经历了古新世—渐新世断陷和中新世—第四纪拗陷两个主要演化阶段,断陷阶段发育陆相河湖相沉积,拗陷阶段发育浅海-半深海沉积。 相似文献
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J. Makris A. Ginzburg P.M. Shannon A.W.B. Jacob C.J. Bean U. Vogt 《Marine and Petroleum Geology》1991,8(4)
A 700 km wide-angle reflection/refraction profile carried out in the central North Atlantic west of Ireland crossed the Erris Trough, Rockall Trough and Rockall Bank, and terminated in the western Hatton-Rockall Basin. The results reveal the presence of a number of sedimentary basins separated by basement highs. The Rockall Trough, with a sedimentary pile up to 5 km thick, is underlain by thinned continental crust 8–10 km thick. Some major fault block structures are identified, especially on the eastern margin of the Rockall Trough and in the adjacent Erris Trough. The Hatton-Rockall Basin is underlain by westward-thinning continental crust 22–10 km thick. Sedimentary strata are up to 5 km thick. The strata in the Rockall Trough and Hatton-Rockall Basin probably range in age from Late Palaeozoic to Cenozoic. However, the basins have different sedimentation histories and differ in structural style. The geometry of the crust and sediments suggests that the Rockall Trough originated by pure shear crustal stretching, associated with rift deposits and Cenozoic thermal sag strata. In contrast, the development of the Erris Trough, located on unthinned continental crust, was facilitated by shallow, brittle extension with little deep crustal attenuation. A two-layered crust occurs throughout the region. The lower crustal velocity in the Hatton-Rockall Basin is higher than that in the Rockall Trough. The velocity structure shows no indication of crustal underplating by upper mantle material in the region. 相似文献
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东海陆架盆地是位于中国东部华南大陆边缘的一个中、新生代叠合盆地,具有较大油气潜力。目前东海陆架盆地油气的发现均来自于新生界,对中生代残留地层的各方面特征认识不足:在空间上通常集中于特定构造单元,且基本位于盆地西部;在时间上主要涉及白垩纪和侏罗纪,且多是定性或半定量的研究。本文在前人研究的基础上,收集、整理了研究区目前最新、最全的反射地震资料和钻井数据,从钻遇中生界井的标定出发,以地震资料的层序划分和解释为基础,进行残留地层的研究,空间上统一盆地东、西两大坳陷带,时间上统揽白垩纪、侏罗纪以及前侏罗纪三个时期。结果表明,东海陆架盆地中生代残留地层遭受了后期严重的剥蚀改造,总体呈现东厚西薄、南厚北薄的特征,残留地层范围随时间不断东扩。对比各时期残留地层平面展布特征,揭示了东海陆架盆地的演变过程:三叠纪时期盆地原型为被动大陆边缘坳陷型盆地,早、中侏罗世时期为活动大陆边缘弧前盆地,晚侏罗世—晚白垩世时期为大陆边缘弧后伸展盆地;与此相对应,古太平洋板块俯冲肇始于晚三叠世—早、中侏罗世时期,板块后撤始于晚侏罗世。东海陆架盆地在中生代的东侧边界位于钓鱼岛隆褶带的东侧。 相似文献
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Structures of the northeasternmost South China Sea continental margin and ocean basin: geophysical constraints and tectonic implications 总被引：2，自引：0，他引：2
Chun-Feng Li Zuyi Zhou Jiabiao Li Hujun Hao Jianhua Geng 《Marine Geophysical Researches》2007,28(1):59-79
The northeastern part of the South China Sea is a special region in many aspects of its tectonics. Both recent drilling into
the Mesozoic and new reflection seismic surveys in the area provide a huge amount of data, fostering new understanding of
the continental margin basins and regional tectonic evolution. At least four half-grabens are developed within the Northern
Depression of the Tainan Basin, and all are bounded on their southern edges by northwestward-dipping faults. One of the largest
half-grabens is located immediately to the north of the Central Uplift and shows episodic uplift from the late Oligocene to
late Miocene. Also during that period, the Central Uplift served in part as a material source to the Southern Depression of
the Tainan Basin. The Southern Depression of the Tainan Basin is a trough structure with deep basement (up to 9 km below sealevel
or 6 km beneath the sea bottom) and thick Cenozoic sedimentation (>6 km thick). Beneath the Southern Depression we identified
a strong landward dipping reflector within the crustal layer that represents a significant crustal fault. This reflector coincides
with a sharp boundary in crustal thicknesses and Moho depths. We show that the northeasternmost South China Sea basin, which
may have undergone unique evolution since the late Mesozoic, is markedly different from the central South China Sea basin
and the Huatung Basin, both geologically and geophysically. The Cenozoic evolution of the region was largely influenced by
pre-existing weaknesses due to tectonic inheritance and transition. The South China Sea experienced multiple stages of Cenozoic
extension. 相似文献
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我国南海历史性水域线的地质特征 总被引：3，自引：1，他引：2
40a的海洋地质、地球物理实测研究表明,九段线不仅是显示我国南海主权的历史性水域线,而且总体上也是南海与东部、南部和西部陆区及岛区的巨型地质边界线。根据实测数据,本文将从地质成因、来源、演化的角度论述此南海历史性水域线的合理性。主要结论包括:历史性水域线的东段在地形上基本与马尼拉海沟一致,海沟西侧为南海中央海盆洋壳区,东侧为菲律宾群岛。根据国际地质研究的资料,菲律宾群岛始新世以前位于较偏南的纬度,后来于中晚中新世(距今16~10Ma)仰冲于南海中央海盆之上,因此菲律宾群岛是一个外来群岛。而黄岩岛在马尼拉海沟以西,是中央海盆洋壳区的一个岛礁,与菲律宾群岛成因不同。南海历史性水域线的南段在地形上基本与南沙海槽一致,伴随南沙地块由北部陆缘向南裂离,古南海洋壳沿此海槽以南俯冲至加里曼丹岛陆壳之下,因此南沙地块与加里曼丹陆块为两个来历不同的地块。南海历史性水域线西段的分布在地形上与越东巨型走滑断裂带基本一致,可能与西沙地块、中沙地块、南沙地块从南海北部陆缘向南滑移有关。南沙地块北缘陡直的正断层结构,突显中央海盆是拉裂形成,其基底和中新生代地层与北部珠江口盆地的地层结构可以对比,说明南沙岛礁原属我国华南大陆南缘,后因南海的形成裂离至现今的位置。 相似文献
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东海新生代构造格架特征与油气关系 总被引：4，自引：0，他引：4
东海海域存在着二个不同时期、不同类型、不同结构秒同成因机制的新生代盆地，即发育在陆壳之上的东海陆架陆缘裂谷盆地和发育在过渡地壳之上的冲绳海槽弧后盆地。前者是大陆向洋蠕散时两次裂离而形成的，后者是洋壳向陆壳俯冲导致陆壳裂离而产生的。 相似文献
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The Unst Basin is situated in the northern North Sea between the East Shetland Basin and the Shetland Isles. The basin is essentially a three-armed, Permo-Triassic fault-controlled basin containing up to 3600 m of red-beds. This is overlain by a westerly thickening Jurassic and early Cretaceous sequence, the stratigraphy of which is very similar to that of the East Shetland Basin. In particular, the Brent Group (140 m), Humber Group (685 m) and Cromer Knoll Group (300 m) are well represented.As a result of Laramide uplift of the area, the thick Upper Cretaceous and Palaeocene strata of the East Shetland Basin are absent from the Unst Basin. This uplift resulted in substantial erosion within the Unst Basin providing the major source for Palaeocene sands in the Viking Graben and the Faeroes Basin. Late Palaeocene and younger Tertiary strata transgress westwards across this erosion surface.Petroleum exploration within the basin culminated in the drilling of two exploration wells. These wells encountered potential reservoir and source rocks in the Jurassic section. However, geochemical analyses indicate these source rocks are immature for hydrocarbon generation within the Unst Basin. It is concluded that the Unst Basin has a low petroleum potential. 相似文献
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A sapropelic layer with organic carbon contents of 1.0–1.5%, in contrast to the usual 0.2–0.5% of adjacent normal basin sediments, is found to be widespread in sediment cores collected from the Cilicia Basin, northeastern Mediterranean. The horizon is thought to be equivalent to the S1 sapropel of other workers. It is finely laminated with no evidence of bioturbation, has a very markedly low magnetic susceptibility, and contains a significantly higher content of pollen and plant debris than is found in the normal basin sediment. The stable oxygen and carbon isotope values suggest that the layer formed during post-glacial climatic warming when fresh nutrient-rich surface water flowed into the Cilicia Basin from the surrounding land to produce a stratified water mass which allowed the development of anoxic bottom waters. The distribution of the sapropelic layer indicates that anoxic conditions extended to within approximately 350 m of sea level during deposition, a depth shallower than previously recorded in the Eastern Mediterranean. 相似文献
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Petrologic perspectives on tectonic evolution of a nascent basin (Okinawa Trough) behind Ryukyu Arc：A review 总被引：9，自引：2，他引：7
Okinawa Trough is a back-arc, initial marginal sea basin, located behind the Ryukyu Arc–Trench System. The formation and evolution of the Okinawa Trough is intimately related to the subduction process of the Philippine Sea Plate beneath the Eurasian Plate since the late Miocene. The tectonic evolution of the trough is similar to other active back-arcs, such as the Mariana Trough and southern Lau Basin, all of which are experiencing the initial rifting and subsequent spreading process. This study reviews all petrologic and geochemical data of mafic volcanic lavas from the Okinawa Trough, Ryukyu Arc, and Philippine Sea Plate, combined with geophysical data to indicate the relationship between the subduction sources(input) and arc or back-arc magmas(output) in the Philippine Sea Plate–Ryukyu Arc–Okinawa Trough system(PROS). The results obtained showed that several components were variably involved in the petrogenesis of the Okinawa Trough lavas: sub-continental lithospheric mantle underlying the Eurasian Plate, Indian mid-oceanic ridge basalt(MORB)-type mantle, and Pacific MORB-type mantle. The addition of shallow aqueous fluids and deep hydrous melts from subducted components with the characteristics of Indian MORB-type mantle into the mantle source of lavas variably modifies the primitive mantle wedge beneath the Ryukyu and subcontinental lithospheric mantle(SCLM) beneath the Okinawa Trough. In the northeastern end of the trough and arc, instead of Indian MORB-type mantle, Pacific MORB-type mantle dominates the magma source. Along the strike of the Ryukyu Arc and Okinawa Trough, the systematic variations in trace element ratios and isotopic compositions reflect the first-order effect of variable subduction input on the magma source. In general, petrologic data, combined with geophysical data, imply that the Okinawa Trough is experiencing the "seafloor spreading" process in the southwest segment, "rift propagation" process in the middle segment, and "crustal extension" process in the northeast segment, and a nascent ocean basin occurs in the southwest segment. 相似文献