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为了预测南黄海盆地油气远景,利用最新采集的383个站位的低层大气烃类检测数据进行评价。烃类检测结果为:高值甲烷异常区主要分布在南黄海北部坳陷西南,次高值甲烷异常区主要分布在中部隆起带西部和南部坳陷中部,而南北向带状分布的甲烷异常带位于南黄海的东部。结合南黄海盆地航磁异常和部分浅地层剖面资料,认为中部隆起带东侧及紧邻的北部坳陷西南具有较好的油气远景。 相似文献
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南黄海盆地是在前震旦系克拉通基础上发育的中、古生界海相与中、新生界陆相多旋回叠合盆地。通过地震资料解释,结合邻区钻井与区域地质资料,对南黄海盆地中部隆起中、古生代地层及其形成演化进行了研究,结果表明,南黄海盆地中部隆起沉积了较全的中、古生界海相地层,发育第四系—新近系、中—下三叠统青龙组、上二叠统、下二叠统—上泥盆统、中—下志留统,奥陶系—震旦系和前震旦系变质岩系等7套地震地质层序;主要经历了前震旦纪基底形成、震旦纪—早古生代克拉通发育、晚古生代—中三叠世稳定台地—陆内裂陷、晚三叠世—古近纪形成与抬升剥蚀及新近纪-第四纪坳陷沉降5个阶段。 相似文献
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南黄海中—新生代盆地经历了中生代印支运动以来的多期构造运动改造,凹陷分隔性强,各凹陷烃源岩发育条件差异大。利用地质调查获得的最新资料,从烃源岩有机质丰度、类型、成熟度以及成熟烃源岩体积参数等方面,重点探讨了中—新生代陆相盆地生烃条件好和较好的7个凹陷的烃源潜力及中—古生界海相烃源岩的演化特征。结果表明,北部坳陷的北部凹陷、东北凹陷以及南部坳陷的南四凹陷属于一类生烃凹陷,北部坳陷的南(西)部凹陷、南部坳陷的南五凹陷属于二类生烃凹陷,而北部坳陷的中—东部凹陷以及南部坳陷的南七凹陷为三类生烃凹陷。印支构造面之下的中—古生界海相层系是盆地内另一套重要烃源岩,其有机质热演化程度分异明显,在中—新生代凹陷间低凸起区最低,坳陷周围的隆起区最高,新生代凹陷区"基底层"内热演化程度介于上述两者之间。 相似文献
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《海洋地质前沿》2017,(4)
东海陆架盆地西部坳陷为整个盆地内重要的二级构造单元之一,发育有多个次级凹陷,完整记录了盆地及周边晚白垩世以来的构造变形信息,能够为解决太平洋板块俯冲、东亚陆缘类型转换等相关科学问题提供参考。基于二维地震剖面解释,并综合前人研究成果,通过对东海陆架盆地西部坳陷的构造分析认为,该坳陷发育有中—新生界两大构造层,由一系列中—新生代裂陷盆地组成,为早白垩世晚期应力场由挤压环境转换为拉张伸展环境下的产物,以伸展构造样式为主,半地堑、掀斜断块、多米诺式断裂等上述伸展构造样式发育。同时,伴随晚白垩世末期的应力反转,坳陷内长江凹陷局部可见有正反转构造样式。坳陷内断裂展布具有不同时期、方向不同、性质各异的特征,而岩浆岩发育则表现出了广泛分布、不同时代、规模和岩性各异的特点,二者皆与区域构造方向基本一致。白垩纪以来,太平洋板块的漂移方向、俯冲角度的多次变化为坳陷现今中—新生代构造格局形成的主要因素,此外后期菲律宾海板块向欧亚板块的碰撞、挤压、俯冲作用使得整个构造格局更加复杂化。 相似文献
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南黄海盆地北部坳陷的东北凹、北凹、中凹、南凹等凹陷发育有多种类型的正反转构造,包括穿透断展型、挤压褶皱型、逆断层型等。主要反转期为渐新世和上新世末,其中渐新世的构造反转影响较大。太平洋—欧亚板块汇聚速率变化是控制南黄海盆地北部坳陷新生代反转构造发育的重要因素。正反转构造有利于油气藏的形成,但反转强度较大时可能使油气藏的保存条件变差。 相似文献
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东海南海构造交接带及其邻近海区(简称交接带)位于中国东部大陆边缘,东邻俯冲板块边界。台湾以北是琉球海沟俯冲带,台湾以南为马尼拉海沟俯冲构造带。区域重磁资料分析结果表明,该东海陆架区存在3条重力高和2条重力低,重力高分别对应于闽浙隆起带、渔山低凸起和陆架外缘隆起,最大值高达50×10-5m·s-2;重力低对应于沉积盆地,最低值在台西南盆地,约为-20×10-5m·s-2。重磁特征表明东海盆地外缘台湾 钓鱼岛构造带具有明显的自由空间异常,磁场为平缓负异常,由古近系、白垩系或更老的变质岩及中新世的侵入岩组成,向南延伸至澎湖隆起。因为澎湖隆起具有高重力异常,放射性年龄表明这些碱性玄武岩形成于17 8～8MaBP,其特征同现在的琉球岛弧一样,可能是残留的古琉球岛弧。台西南盆地南侧(上陆坡)的凸起具有类似的幅度异常,呈ENE—WSW向,并消失在台西南盆地南段。新生代以来,盆地张裂活动具有不同时性,并向陆架边缘变得年轻。东海大陆边缘盆地属弧后残留盆地成因,多因岛弧的迁移而新生,但珠江口盆地则是被动大陆边缘裂陷作用所致。 相似文献
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在对南黄海盆地海相中、古生界烃源条件和后期保存条件研究的基础上,运用盆地模拟手段并结合前人研究成果,对海相地层烃源岩的排烃史进行了模拟,计算了海相地层油气资源量,从而进行了海相油气资源潜力的分析;同时通过对海相上构造层和下构造层两套含油气系统成藏条件的研究,预测了盆地内海相油气资源的有利运聚区,进而指出南黄海盆地海相油气勘探的有利区,为下一步南黄海盆地的勘探部署提供了依据。研究表明,南黄海盆地海相下构造层和海相上构造层栖霞组、龙潭组—大隆组烃源岩推测为好的烃源岩,海相上构造层青龙组烃源岩推测为中等—好的烃源岩;盆地海相地层具有一定的油气资源潜力,油气资源总量为35.37×10^8t,且在纵向上,油气资源主要来自海相下构造层烃源岩系,在平面上主要分布于南部坳陷;盆地海相地层存在两类油气资源勘探有利区,其中,最有利区位于中部隆起区南部、南部坳陷区和勿南沙隆起区北部。 相似文献
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南黄海中部隆起地层分布特征 总被引：11，自引：1，他引：10
南黄海中部隆起是南黄海盆地构造最稳定的地区之一,也是下古生界含油气远景区之一,其找油前景引起人们极大的关注。应用小波分析等方法处理南黄海重磁异常场,揭示中部隆起区结晶基底起伏特征,同时结合区域地质以及地震剖面资料,对中部隆起地层分布特征提出了几点新认识:南黄海中部隆起结晶基底的起伏特征并非"平板"一块,其平面总体轮廓可概括为"三隆两坳";受印支运动的影响,中部隆起区发育的主要地层是震旦系-下二叠统,下三叠统青龙灰岩和上二叠统龙潭煤系已基本剥蚀殆尽;下古生界沉积中心大致位于结晶基底"坳陷"部位;上古生界受火山活动和岩浆侵入的影响,分布特征是分段而不连片;中部隆起分布着火山岩,分布特征是"东强西弱"。 相似文献
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Chandralata Raghukumar G. Sheelu P. A. Loka Bharathi Shanta Nair C. Mohandass 《Marine Georesources & Geotechnology》2001,19(1):1-16
In order to assess the impact of deep-sea mining on the in situ benthic life, we measured the microbial standing stock and concentration of organic nutrients in the deep-sea sediments of the Central Indian Ocean Basin in the Indian pioneer area. Sediments were collected using box core and grab samples during September 1996. The total bacterial numbers ranged from 10 10 -10 11 cells per g -1 dry weight sediment. There was a marginal decrease in the number of bacteria from surface to 30 cm depth, though the subsurface section registered a higher number than did the surface. The highest numbers were encountered at depths of 4-8 cm. The retrievable number of bacteria were two orders less in comparison with the direct total counts of bacteria. An almost homogeneous distribution of bacteria, total organic carbon, living biomass, and lipids throughout the depth of cores indicates active microbial and benthic processes in the deep sea sediments. On the other hand, a uniform distribution of total counts of bacteria, carbohydrates, and total organic carbon in all the cores indicates their stable nature and suggests that they can serve as useful parameters for long-term monitoring of the area after the benthic disturbance. Further studies on temporal variability in this region would not only verify the observed norms of distribution of these variables but would also help to understand restabilization processes after the simulated benthic disturbance. 相似文献
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Arne Schnack-Friedrichsen Angela M. Davis Jim D. Bennell Dei G. Huws 《Marine Georesources & Geotechnology》2001,19(4):221-243
The interdependence between the seismo-acoustic properties of a marine sediment and its geotechnical/physical parameters has been known for many years, and it has been postulated that this should allow the extraction of geotechnical information from seismic data. Though in the literature many correlations have been published for the surficial layer, there is a lack of information for greater sediment depths. In this article, a desktop study on a synthetic seafloor model illustrates how the application of published near-surface prediction equations to subsurface sediments (up to several tens of meters burial depth) can lead to spurious predictions. To test this further, acoustic and geotechnical properties were measured on a number of sediment core samples, some of which were subjected to loading in acoustically-equipped consolidation cells (oedometers) to simulate greater burial depth conditions. For low effective pressures (representing small burial depths extending to around 10 meters subsurface), the general applicability of established relationships was confirmed: the prediction of porosity, bulk density, and mean grain size from acoustic velocity and impedance appears generally possible for the investigated sedimentary environments. As effective pressure increases through, the observed relationships deviate more and more from the established ones for the near-surface area. For the samples tested in this study, in some instances increasing pressure even resulted in decreasing velocities. There are several possible explanations for this abnormal behavior, including the presence of gas, overconsolidation, or bimodal grain size distribution. The results indicate that an appropriate depth correction must be introduced into the published prediction equations in order to obtain reliable estimates of physical sediment properties for greater subsurface depths. 相似文献
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Derek V. Ellis 《Marine Georesources & Geotechnology》2001,19(1):51-63
This article reviews information recently available from existing marine and coastal mining for responses to environmental issues affecting marine mining at different depths. It is particularly but not exclusively concerned with those issues affecting seabed biodiversity impact and recovery. Much information has been gathered in the past 10 years from shallow mining operations for construction aggregate, diamonds, and gold, from coastal mines discharging tailings to shallow and deep water, and from experimental deep mining tests. The responses to issues identified are summarized in a series of eight tables intended to facilitate site-specific consideration. Since impacts can spread widely in the surface mixing layer SML, and can affect the biologically productive euphotic zone, the main issues considered arise from the depth of mining relative to the SML of the sea. Where mining is below the SML, the issue is whether it is environmentally better to bring the extraction products to the surface vessel for processing (and waste discharge), or to process the extraction products as much as possible on the seabed. Responses to the issues need to be sitespecific, and dependent on adequate preoperational environmental impact and recovery prediction. For deep tailings disposal from a surface vessel, there are four important environmental unknowns: (1) the possible growth of "marine snow" (bacterial flocs) utilizing the enormous quantities of fine tailings particles (hundreds or thousands of metric tons per day) as nuclei for growth, (2) the possibility that local keystone plankton and nekton species may migrate diurnally down to and beyond the depth of deep discharge and hence be subjected to tailings impact at depth, (3) the burrow-up capability of deep benthos and their ability to survive high rates of tailings deposition, and (4) the pattern and rate of dispersion of a tailings density current through the deep water column from discharge point to seabed. Actions to obtain relevant information in general and site-specifically are suggested. 相似文献
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G. Parthiban 《Marine Georesources & Geotechnology》2000,18(3):223-235
Particle fluxes were measured 7 m above the sea bottom during the predisturbance, disturbance, and postdisturbance periods by using time series sediment traps attached to seven deep-sea moorings deployed in the INDEX experiment site in the Central Indian Basin. The predisturbance particle fluxes varied between 22.3 to 55.1 mg m -2 day -1 . Increased and variable particle fluxes were recorded by the sediment traps during the disturbance period. The increase observed was 0.5 to 4 times more than the background predisturbance fluxes. The increases in particle fluxes (~4 times) recorded by the sediment trap located in the southwestern direction (DMS-1) were the greatest, which could be the result of preferential movement of resuspended particles generated during the deep-sea benthic disturbance along the general current direction prevailing in this area during the experimental period. Also, the traps located closer to the disturbance area recorded greater fluxes than did the traps far away, across the Deep Sea Sediment Resuspension System path. This variability in recorded particle fluxes by the traps around the disturbance area clearly indicates that physical characteristics such as grain size and density of the resuspended particles produced during the disturbance had an important effect on particle movement. The postdisturbance measurements during ~5 days showed a reduction in particle fluxes of ~50%, indicating rapid particle settlement. 相似文献
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海上大直径钢管桩打桩过程中,桩周土体受到强烈扰动而发生强度弱化,掌握桩周土体强度弱化规律对于准确预测打桩过程、保证工程安全具有重要意义。为研究土体强度弱化规律,开展了环剪试验模拟打桩对桩周土体的扰动,测试土体强度随剪切速率的变化规律,建立了描述土体强度弱化规律的拟合公式,引入到打桩分析软件中。研究结果表明：土体的强度折减程度不仅与土体本身的性质有关还受到土体的埋深和剪切速率的影响,埋深越深土体强度折减程度越低,剪切速率越高土体强度折减越高,在打桩分析中可采用这里推荐的线性折减方法来模拟不同深度处土体强度的折减规律。 相似文献
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Geoacoustic Inversion via Genetic Algorithm and Its Application to Manganese Sediment Identification
An acoustic inversion method using a wide-band signal and two near field receivers is proposed and applied to multiple layered seabed models including a manganese sediment. The inversion problem can be formulated into a probabilistic model comprised of signals, a forward model, and additive noise. The forward model simulates wide-band signals, such as chirp signals, and is chosen to be the source-waveletconvolution plane wave modeling method. The wavelet matching technique, using weighted least-squares fitting, estimates the sediment sound-speed and thickness on which determination of the possible numerical ranges for a priori uniform distribution is based. The genetic algorithm is applied to a global optimization problem to find a maximum a posteriori solution for determined a priori search space. Here the object function is defined by an L 2 norm of the difference between measured and modeled signals. Not only the marginal pdf but also its statistics are calculated by numerical evaluation of integrals using the samples selected during importance sampling process of the genetic algorithm. 相似文献
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The advanced piston corer (APC) has been used by the Ocean Drilling Program since 1985 for recovering soft sediments from the ocean floor. The pullout force measured on extracting the core barrel from the sediment is shown to correlate with the average shear strength of the sediment core measured in the ship's laboratory. A simple rule of thumb is derived relating the shear strength of the sediment to the pullout force. Multiple APC holes at individual sites allow the consistency of the pullout measurements to be assessed. The effects of different operational procedures during APC coring are also explored. Although generally applicable, the correlation between pullout force and laboratory measurements of shear strength breaks down for some APC holes, possibly because of the disturbance of some sediment types during the APC coring process. A better understanding of the physical process of APC coring, and its effect on the properties of the sediment both inside and immediately outside the core barrel, would indicate what confidence can be put on the measurement of pullout force as a way of evaluating the in situ shear strength of deep sea sediments. 相似文献
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Shigehisa Nakamura 《Marine Geodesy》2000,23(1):55-61
Specific properties of the interannual sea level variations and annual tides in the Northwestern Pacific were studied. Several tide stations were monitored. The monthly mean sea level for the year of 1995 was analyzed at each tide station. A seismic event in 1995, some tectonic activity around the subject area, and the Kuroshio (the oceanic western boundary current) may possibly contaminate results which would have occurred from the astronomical annual tide alone. 相似文献
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