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1.
南黄海西部海域高分辨率声学地层及其沉积环境 总被引：4，自引：0，他引：4
通过对高分辨率浅地层剖面的分析解译,对南黄海西部陆架区进行了声学地层划分。南黄海西部海域声学地层剖面可划分为5套地层Ⅰ、Ⅱ1、Ⅱ2、Ⅲ1、Ⅲ2,每套地层代表一次全球性(或区域性)海平面变化周期内的海进一海退这样一个完整的旋回变化过程所形成的海侵或海退沉积层序。将典型声学地层剖面与区内钻孔岩心的沉积地层岩性单元对比研究,得到各声学反射层的时代、岩性及沉积环境。并发现依据浅地层进行的声学地层划分与钻孔岩心的地质地层划分有较好的对应关系。结合区内钻孔岩心的分析结果,对晚更新世以来南黄海陆架区的沉积环境及沉积过程进行了探讨。 相似文献
2.
海底天然气渗漏是海洋环境中广泛分布的自然现象,在世界各大洋中都有发现。海底渗漏可以极大地改变海底地貌特征,形成多种与之相关的微地貌类型。海底渗漏和天然气水合物的赋存具有密切的关系,海底渗漏区常伴有埋藏浅、饱和度高的天然气水合物。对南海东北部陆坡海域浅地层剖面、多波束测深和地震反射剖面等资料进行综合研究,识别出海底麻坑、海底丘状体、大型海底圆丘、泥火山等与海底天然气渗漏有关的微地貌类型,且麻坑、海底丘状体／大型海底圆丘、泥火山微地貌分别代表了浅覆盖层快速天然气渗漏、浅覆盖层中等速度天然气渗漏和厚覆盖层快速天然气渗漏3种天然气渗漏模式。以海底丘状体微地貌及声空白反射特征的浅层天然气聚集带,成为块状水合物最理想的发育场所,这可能成为南海北部陆坡勘察块状水合物的重要识别标志。 相似文献
3.
南海北部湾海洋工程地质特征 总被引：8，自引：0，他引：8
根据地球物理、声学探测及海底取样等实测资料详细分析,发现北部湾油气勘探开发区具有近岸、水浅等优越自然条件以及复杂的海洋工程地质特征。海底地形地貌较为复杂,存在潮流沙脊与潮沟、海底沙坡、埋藏古河道、浅层气、埋藏古陡坡、滑塌断层及可能的砂土液化层等潜在灾害地质因素,对海上构筑物存在直接或潜在的危险性。尤其在东部,海底坎坷不平,活动性的潮流消脊、侵蚀沟槽、海底沙波及浅层气等很发育,是海底工程建设的危险区,应引起高度重视。 相似文献
4.
Very high resolution seismic profiles, ground-truthed by vibrocores, have revealed the occurrence of kilometre-scale acoustic
turbidity in the Marennes-Oléron Bay, France. Such acoustic turbidity is commonly interpreted as gas-charged sediments. Comparison
between accurate historical bathymetric data and the present day bathymetry has shown high sediment accretion zones in the
study area (locally up to 8 m since 1824). The superimposition of seismic and bathymetric datasets displays a striking correlation
between the high sedimentation rate area and the boundaries of the acoustic turbidity, i.e. gas-charged sediments. The key
role of sedimentation rates in shallow gas generation in the study area is pointed out. It is also concluded that shallow
gas is probably generated at short (decadal to secular) time scales. 相似文献
5.
Geological Characteristics and Distribution of Submarine Physiographic Features in the Taiwan Region
《Marine Georesources & Geotechnology》2013,31(3-4):139-153
The sea floor topography around Taiwan is characterized by the asymmetry of its shallow and flat shelves to the west and markedly deep troughs and basins to the south and east. Tectonics and sedimentation are major controls in forming the submarine physiographic features around Taiwan. Three Pliocene-Quaternary shelves are distributed north and west of Taiwan: East China Sea Shelf (passive margin shelf), the Taiwan Strait Shelf (foreland shelf), and Kaoping Shelf (island shelf) from north to south parallel to the strike of Taiwan orogen. Off northeastern Taiwan major morpho/tectonic features associated with plate subduction include E-W trending Ryukyu Trench, Yaeyama accretionary wedge, forearc basins, the Ryukyu Arcs, and the backarc basin of southern Okinawa Trough. Off eastern Taiwan lies the deep Huatung Basin on the Philippine Sea plate with a relatively flat floor, although several large submarine canyons are eroding and crossing the basin floor. Off southeastern Taiwan, the forearc region of the Luzon Arc has been deformed into five alternating N-S trending ridges and troughs during initial arc-continent collision. Among them, the submarine Hengchun Ridge is the seaward continuation of the Hengchun peninsula in southern Taiwan. Off southwestern Taiwan, the broad Kaoping Slope is the major submarine topographic feature with several noticeable submarine canyons. The Penghu Canyon separates this slope from the South China Sea Slope to the west and merges southwards into the Manila Trench in the northern South China Sea. Although most of sea floors of the Taiwan Strait are shallower than 60?m in water depth, there are three noticeable bathymetric lows and two highs in the Taiwan Strait. There exists a close relationship between hydrography and topography in the Taiwan Strait. The circulation of currents in the Taiwan Strait is strongly influenced by seasonal monsoon and semidiurnal tides. The Penghu Channel-Yunchang Ridge can be considered a modern tidal depositional system. The Taiwan Strait shelf has two phases of development. The early phase of the rift margin has developed during Paleoocene-Miocene and it has evolved to the foreland basin in Pliocene-Quaternary time. The present shelf morphology results mainly from combined effects of foreland subsidence and modern sedimentation overprinting that of the Late Pleistocene glaciation about 15,000 years ago. 相似文献
6.
Geological Characteristics and Distribution of Submarine Physiographic Features in the Taiwan Region
Ho-Shing Yu 《Marine Georesources & Geotechnology》2003,21(3):139-153
The sea floor topography around Taiwan is characterized by the asymmetry of its shallow and flat shelves to the west and markedly deep troughs and basins to the south and east. Tectonics and sedimentation are major controls in forming the submarine physiographic features around Taiwan. Three Pliocene-Quaternary shelves are distributed north and west of Taiwan: East China Sea Shelf (passive margin shelf), the Taiwan Strait Shelf (foreland shelf), and Kaoping Shelf (island shelf) from north to south parallel to the strike of Taiwan orogen. Off northeastern Taiwan major morpho/tectonic features associated with plate subduction include E-W trending Ryukyu Trench, Yaeyama accretionary wedge, forearc basins, the Ryukyu Arcs, and the backarc basin of southern Okinawa Trough. Off eastern Taiwan lies the deep Huatung Basin on the Philippine Sea plate with a relatively flat floor, although several large submarine canyons are eroding and crossing the basin floor. Off southeastern Taiwan, the forearc region of the Luzon Arc has been deformed into five alternating N-S trending ridges and troughs during initial arc-continent collision. Among them, the submarine Hengchun Ridge is the seaward continuation of the Hengchun peninsula in southern Taiwan. Off southwestern Taiwan, the broad Kaoping Slope is the major submarine topographic feature with several noticeable submarine canyons. The Penghu Canyon separates this slope from the South China Sea Slope to the west and merges southwards into the Manila Trench in the northern South China Sea. Although most of sea floors of the Taiwan Strait are shallower than 60 m in water depth, there are three noticeable bathymetric lows and two highs in the Taiwan Strait. There exists a close relationship between hydrography and topography in the Taiwan Strait. The circulation of currents in the Taiwan Strait is strongly influenced by seasonal monsoon and semidiurnal tides. The Penghu Channel-Yunchang Ridge can be considered a modern tidal depositional system. The Taiwan Strait shelf has two phases of development. The early phase of the rift margin has developed during Paleoocene-Miocene and it has evolved to the foreland basin in Pliocene-Quaternary time. The present shelf morphology results mainly from combined effects of foreland subsidence and modern sedimentation overprinting that of the Late Pleistocene glaciation about 15,000 years ago. 相似文献
7.
An experiment aboard the Scripps Institution of Oceanography's RV Thomas Washington has demonstrated the seafloor mapping advantages to be derived from combining the high-resolution bathymetry of a multibeam echo-sounder with the sidescan acoustic imaging plus wide-swath bathymetry of a shallow-towed bathymetric sidescan sonar. To a void acoustic interference between the ship's 12-kHz Sea Beam multibeam echo-sounder and the 11-12-kHz SeaMARC II bathymetric sidescan sonar system during simultaneous operations, Sea Beam transmit cycles were scheduled around SeaMARC II timing events with a sound source synchronization unit originally developed for concurrent single-channel seismic, Sea Beam, and 3.5-kHz profile operations. The scheduling algorithm implemented for Sea Beam plus SeaMARC II operations is discussed, and the initial results showing their combined seafloor mapping capabilities are presented 相似文献
8.
随着油气资源开发向深水区发展,迫切需要采用一定的方法去了解块体运动的特征以及分析块体运动对深水油气资源开发的可能性.本文阐述了东海陆坡块体运动地形分析方法以及多种数据处理技术的使用.多波束测深系统为人们提供了直观的海底地貌形态特征,地层剖面仪系统能探测海底以下沉积物性质和结构的变化.GIS、Fledermaus、Delph等软件系统可以定量分析海底微地貌形态特征. 相似文献
9.
Gas in sediments has become an important subject of research for various reasons. It affects large areas of the sea floor
where it is mainly produced. Gas and gas migration have a strong impact on the environmental situation as well as on sea floor
stability. Furthermore, large research programs on gas hydrates have been initiated during the last 10 years in order to investigate
their potential for future energy production and their climatic impact. These activities require the improvement of geophysical
methods for reservoir investigations especially with respect to their physical properties and internal structures. Basic relationships
between the physical properties and seismic parameters can be investigated in shallow marine areas as they are more easily
accessible than hydrocarbon reservoirs. High-resolution seismic profiles from the Arkona Basin (SW Baltic Sea) show distinct
‘acoustic turbidity’ zones which indicate the presence of free gas in the near surface sediments. Total gas concentrations
were determined from cores taken in the study area with mean concentrations of 46.5 ml/l wet sediment in non-acoustic turbidity
zones and up to 106.1 ml/l in the basin centre with acoustic turbidity. The expression of gas bubbles on reflection seismic
profiles has been investigated in two distinct frequency ranges using a boomer (600–2600 Hz) and an echosounder (38 kHz).
A comparison of data from both seismic sources showed strong differences in displaying reflectors. Different compressional
wave velocities were observed in acoustic turbidity zones between boomer and echosounder profiles. Furthermore, acoustic turbidity
zones were differently characterised with respect to scattering and attenuation of seismic waves. This leads to the conclusion
that seismic parameters become strongly frequency dependent due to the dynamic properties of gas bubbles. 相似文献
10.
High-resolution and high-density 2-D multichannel seismic data, combined with high-precision multibeam bathymetric map, are utilized to investigate the characteristics and distribution of submarine landslides in the middle of the northern continental slope, South China Sea. In the region, a series of 19 downslope-extending submarine canyons are developed. The canyons are kilometers apart, and separated by inter-canyon sedimentary ridges. Numerous submarine landslides, bounded by headscarps and basal glide surfaces, are identified on the seismic profiles by their distorted to chaotic reflections. Listric faults and rotational blocks in head areas and compressional folds and inverse faults at the toes of the landslides are possibly developed. Three types of submarine landslides, i.e., creeps, slumps, and landslide complexes, are recognized. These landslides are mostly distributed in the head areas and on the flanks of the canyons. As the most widespread landslides in the region, creeps are usually composed of multiple laterally-coalesced creep bodies, in which the boundaries of singular component creep bodies are difficult to delineate. In addition, a total of 77 landslides are defined, including 61 singular slumps and 16 landslide complexes that consist of two or more component landslides. Statistics show that most landslides are of a small dimension (0.53–18.09 km² in area) and a short runout distance (less than 3.5 km). Regional and local slope gradients and rheological behavior of the displaced materials might play important roles in the generation and distribution of the submarine landslides. A conceptual model for the co-evolution of the canyons and the associated landslides in the study area is presented. In the model it is assumed that the canyons are initiated from gullies created by landslides on steeper sites of the continental slope. The nascent canyons would then experience successive retrogressive landsliding events to extend upslope; at the same time canyon downcutting or incision would steepen the canyon walls to induce more landslides. 相似文献
11.
塘沽海区海底地形的SAR影像仿真与反演研究 总被引：1，自引：0，他引：1
利用袁业立、金梅兵(1997)提出的海底地形SAR影像仿真与反演模型，对渤海塘沽海区的一张Radarsat SAR影像进行了仿真和水深反演研究。研究结果表明：仿真影像与真实SAR影像基本吻合，反演水深与实际水深也有较好的一致性；进一步证实了袁业立(1997)SAR成像机理的正确性和在中国近海利用SAR影像进行浅海水深探测的可行性。 相似文献
12.
Slope-confined submarine canyons in the Baiyun deep-water area,northern South China Sea: variation in their modern morphology 总被引：1，自引：0，他引：1
X. S. Li Q. J. Zhou T. Y. Su L. J. Liu S. Gao S. W. Zhou 《Marine Geophysical Researches》2016,37(2):95-112
On the basis of newly collected multibeam bathymetric data, chirp profiles and existing seismic data, we presented a detailed morphological interpretation of a series of slope-confined canyons in water depths of 300–2000 m in the Baiyun deep-water area, northern margin of the South China Sea. Although these canyons are commonly characterized by regular spacing and a straight-line shape, they vary in their lengths, starting and ending water depths, canyon relief, slope gradients, wall slope gradients and depth profiles along the axis. The eastern canyons (C1–C8) have complex surface features, low values in their slope gradient, canyon relief and wall slope gradient and high values in their length and starting and ending depth contrasting to the western ones (C9–C17). From the bathymetric data and chirp profiles, we interpret two main processes that have controlled the morphology and evolution of the canyons: axial incision and landsliding. The western part of the shelf margin where there were at least four stages of submerged reefs differs from the eastern part of the shelf margin where sedimentary undulations occurred at a water depth of ~650 m. We consider that the variation in morphology of submarine canyons in the study area is the result of multiple causes, with the leading cause being the difference in stability of the upper slope which is related to the submerged reefs and sedimentary undulations. 相似文献
13.
Zvi Ben-Avraham Yoram Shoham Eitan Klein Haim Michelson Colette Serruya 《Marine Geophysical Researches》1980,4(3):257-276
A magnetic survey of Lake Kinneret (Sea of Galilee) was conducted on a 1 km grid of north-south and east-west lines. The results indicate that the margins of the lake are associated with large amplitude anomalies, while the centre is quite smooth. The largest anomaly, more than 500 nT, was detected in the vicinity of the entrance of the Jordan River into the lake. Its source is interpreted to be Late Cenozoic basaltic flows. The lake's margins are associated with faults, hot springs and magnetic anomalies. A broad magnetic anomaly trending east-northeast extends from Ginosar Valley into the lake through most of the lake's width. The distribution of basalt flows of different ages and the various structures of the magnetized layers are all contributing to the magnetic anomaly pattern. 相似文献
14.
Wonn Soh 《Progress in Oceanography》2003,57(1):109-124
Sagami Bay is a deep-water foreland basin with an average sedimentary rate of approximately 0.1 g/cm2/year. It is an appropriate area to study for better understanding of sedimentary processes in a setting with a high sedimentation rate. Seven multiple core samples, 30-50 cm thick, were obtained from Sagami Bay. Four of the core samples were taken from the Tokyo submarine fan system (Tokyo canyon floor, Tokyo fan valley and its levee, the distal fan margin). Two samples were obtained from the Sakawa fan delta and the adjacent topographic high. The remaining one was from an escarpment of the Sagami submarine fault. Variations in chemical composition can be recognized at every coring site. They show two different sediment sources: the sediments of the Tokyo submarine fan system and those from Sakawa fan delta. Further, there are differences in chemical composition between canyon floor and levees even within the Tokyo submarine fan system. The results suggest that the sedimentary process is strongly controlled not by vertical particle settling but by a hyperpycnal flow process. The proxies obtained from the core samples do not reflect conditions in the water column immediately overlying the sea floor. Rather, they are controlled by conditions on the adjacent continental shelf or/and shallow basins, which are the areas of primary accumulation. 相似文献
15.
High resolution Chirp and Sparker data allowed definition and mapping of distinct seismic units in the shallow sediment record (~100 ms) acquired from the southern exit of the Bosphorus Strait; a dynamic depositional environment. The bottommost unit observed in the Chirp data (unit-3) is made up of marine-lacustrine sediments thinning seaward and onlaps the basement rocks which are represented by folded strata in the Sparker data, possibly lower to middle Pleistocene age. It is overlain by a series of prograding deposits along the shelf (unit-2) referring to sediment input from the northern sector depending on the water levels of the paleo Marmara lake’s during MIS 3. The uppermost deposits (unit-1) close to the Bosphorus Strait were represented by three separate subunits, unlike to relatively thin drape of sediments observed at the other places in the surrounding regions. The detailed definition of these subunits deduced from the closely-spaced reflection profiles and available radiocarbon ages helped to explain the history of the latest stratigraphic development depending on the connections between the Black Sea and the Sea of Marmara. In addition to the previously proposed major conduits, which controlled the sedimentary deposition at the southern exit of the Bosphorus, namely the Bosphorus Strait and Kurba?al?dere River, another submarine sedimentary pathway at the eastern bank of the strait’s channel seems to have delivered sediments directly into the basin. 相似文献
16.
Neslihan Ocako?lu 《Geo-Marine Letters》2012,32(1):17-28
New (2009) multi-beam bathymetric and previously published seismic reflection data from the NE-SW-oriented Fethiye Bay and
the neighboring N-S-oriented Marmaris Bay off SW Anatolia were evaluated in order to interpret the seafloor morphology in
terms of the currently still active regional tectonic setting. This area lies between the Pliny Trench, which constitutes
the eastern sector of the subduction zone between the African and Eurasian plates in the Eastern Mediterranean, and the Fethiye-Burdur
Fault Zone of the Anatolian Plate. The bathymetric data document the very narrow shelf of the Anatolian coast, a submarine
plain between the island of Rhodes and Marmaris Bay, and a large canyon connecting the abyssal floor of the Rhodes Basin with
Fethiye Bay. The latter are here referred to as the Marmaris Plain and Fethiye Canyon, respectively. Several active and inactive
faults have been identified. Inactive faults (faults f1) delineate a buried basin beneath the Marmaris Plain, here referred
to as the Marmaris Basin. Other faults that affect all stratigraphic units are interpreted as being active. Of these, the
NE-SW-oriented Marmaris Fault Zone located on the Marmaris Plain is interpreted as a transtensional fault zone in the seismic
and bathymetric data. The transtensional character of this fault zone and associated normal faults (faults f3) on the Marmaris
Plain correlates well with the Fethiye-Burdur Fault Zone on land. Another important fault zone (f4) occurs along the Fethiye
Canyon, forming the northeastern extension of the Pliny Trench. The transpressional character of faults f4 inferred from the
seismic data is well correlated with the compressional structures along the Pliny Trench in the Rhodes Basin and its vicinity.
These observations suggest that the Marmaris Fault Zone and faults f3 have evolved independently of faults f4. The evidence
for this missing link between the Pliny Trench and the Fethiye-Burdur Fault Zone implies possible kinematic problems in this
tectonic zone that deserve further detailed studies. Notably, several active channels and submarine landslides interpreted
as having been triggered by ongoing faulting attest to substantial present-day sediment transport from the coast into the
Rhodes Basin. 相似文献
17.
Emin Demirbağ Hülya Kurt Doğa Düşünür Kerim Sarıkavak Suna Çetin 《Marine Geophysical Researches》2007,28(4):343-353
In this study we made a comparative interpretation of multibeam bathymetric and seismic reflection data with different resolutions
and penetration properties collected in the Central Basin of the Marmara Sea. Our main objectives were (i) to investigate
and compare the active tectonic deformation observed on the sea bottom and within the uppermost sedimentary layers to that
of the deep-seated deformation within the limits of resolution and penetration of the available geophysical data and (ii)
to build a three-dimensional (3D) block diagram of the active tectonic and buried features by means of a sliced mapping technique. In this approach, we produced slice maps of the active and buried structural features at selected depths and then combined
them to form a 3D structural block diagram. Motivation for our work was to produce a 3D structural diagram to derive a more
detailed image of the structural features in the Central Basin where there is no available 3D seismic data. The observations
from the bathymetry and seismic data and developed 3D diagram support the presence of a through-going strike-slip fault that
forms a rotational depression zone against a right-stepping strike-slip faulting causing a pull-apart basin in the Central
Depression zone. 相似文献
18.
19.
Morphostructure of the Egyptian Continental Margin: Insights from Swath Bathymetry Surveys 总被引：1，自引：0，他引：1
Jean Mascle Olivier Sardou Lies Loncke Sébastien Migeon Laurent Caméra Virginie Gaullier 《Marine Geophysical Researches》2006,27(1):49-59
In the Eastern Mediterranean, offshore Egypt, the Nile continental margin is characterized by a large deep water turbiditic
system known as the Nile Deep Sea Fan. This post-Miocene terrigenous construction covers an approximately 10 km-thick sedimentary
pile, including 1–3 km of Messinian salt layers. Systematically collected swath bathymetric data proved to be the most powerful
tool to discover, describe and study many sea floor features of this sedimentary construction which reflects competition between
active tectonic, sedimentary, and geochemical processes. Gravity tectonics, triggered by underlying mobile salt layers, construction
of channel-levee systems, the passage of turbidite flows, sedimentary slope failures at various scales, massive mud expulsions
and fluid seepages are all interfering to shape the Nile Deep Sea Fan seabed. 相似文献
20.
南海北部白云深水区水道与朵体沉积序列及演化 总被引：6，自引：0，他引：6
近年来,深水水道、朵体已成为油气勘探的重要目标,南海北部白云深水区发育大量深水水道-朵体沉积体系。研究现今陆坡深水沉积过程有助于揭示深海沉积分布、沉积演化规律。在回顾深水层序地层研究的基础上,利用近地表高分辨率三维地震资料所揭示的地震反射(下超点和上超点迁移)特征研究深水沉积序列,初步探讨不同时期深水水道-朵体体系沉积动力机制,深水水道-朵体体系具有垂向的前积、加积和退积特征,并提出一种深水水道-朵体体系沉积层序模式,低位体系域早期,发育碎屑流或滑块为主的水道-朵体体系,后期则转化为浊流为主的水道-朵体体系。在深水等时地层格架内研究现代深海沉积过程及其产物,对深水储层预测具有十分重要的意义。 相似文献