共查询到20条相似文献，搜索用时 46 毫秒
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《海洋科学集刊》2016,(0)
本文以科学引文索引扩展版(science citation index expanded,SCIE)数据库和社会科学引文索引(social sciences citation index,SSCI)数据库中有关海沟研究的文献为数据源,利用Thomson Data Analyzer、Ucinet、VOSviewer和Excel分析软件,结合PathFinder算法,对检索到的数据进行数据挖掘和定量分析,通过揭示国际上关于海沟研究的主要国家或地区机构之间的合作及其发文情况,总结国际上有关海沟研究领域的发展态势,以期把握海沟研究的整体发展状况,为科研人员进一步研究提供较详尽的参考资料。 相似文献
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1995年3月4日,日本海洋科技中心“横须贺”号工作母船成功地将无人潜水探测机“海沟”号沉放到马里亚纳海沟最深处,并查明世界最深海沟的深度为10 911.4米。“海沟”号今后将着重调查马里亚纳海沟下的板块变形状况,为研究发生地震的原因提供第一手资料。还将调查马里亚纳海沟和伊豆小 相似文献
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菲律宾海周边的深海沟地貌 总被引：2，自引：0，他引：2
菲律宾海是西太平洋最大的边缘海,它处在东海、南海和太平洋之间,被周围的岛弧、海岭所围绕,在每个岛弧东坡或东南坡的坡脚都存有深海沟,菲律宾海就被其周边的深海沟所环绕。学者们对这些深海沟曾有过许多报道,本文依据前人的资料和本所的部分资料对这些深海沟作以下整体的研究。1 菲律宾海周边的深海沟菲律宾海周边的深海沟和海槽呈链状环绕着菲律宾海,它们是西南缘的菲律宾海沟,西北缘的琉球海沟,东至东南缘的伊豆-小笠原海沟、北马尼亚纳海沟(硫黄海沟)和马尼亚纳海沟,南缘的雅浦海沟和帛琉海沟。此外在西缘有北吕宋海槽,在北至西北缘有… 相似文献
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《热带海洋学报》2017,(6)
俯冲的大洋板块在自身的重力以及上覆板块的挤压下,下潜时牵引洋底向下倾伏,从而形成了深邃的海沟。板块及其所携带的沉积物在这里俯冲到地幔深处,构成了全球物质循环的重要部分。海沟地处极端环境,海沟沉积物的沉积作用不同于陆架和浅海地区,其物源和水动力基本控制了沉积模式,但海沟沉积物的物源、沉积环境和沉积机理则更为复杂。海沟沉积物受控于各种类型的构造运动,包括由上覆板块刮削下来的深海沉积物和洋壳碎片堆积而成的沉积增生楔;由海沟重力滑塌、地震等因素引发的浊流沉积;以及由火山活动带来的火山物质等。同时,海沟沉积物也受控于海沟逐渐形成过程中和形成后的各种沉积作用,例如生物化学沉积和漏斗效应。由于海沟沉积物的沉积过程受到漏斗效应的影响,使得海沟沉积一般比深海盆地堆积速度更快,堆积厚度也更大,但在海沟的不同位置或不同海沟之间,堆积厚度也会有所不同。海沟的这些沉积机理和沉积过程的差异,影响了海沟沉积物的性质,包括沉积物粒度、矿物、生物等都有所差异。文章根据海沟以上的沉积特点,分析了不同海沟之间和同一海沟内部海沟沉积厚度以及沉积物的粒度特征、矿物组成和生物特征的差异,并总结了海沟重力滑塌、浊流沉积、火山活动、生物化学沉积、漏斗效应这五种海沟沉积机理对海沟沉积物沉积过程的影响。文章最后展望了海沟沉积物的研究热点,希望在此基础上促进海沟沉积物的进一步研究。 相似文献
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海沟通常拥有全球最深的区域--深渊,由于地理位置、地形地貌和气候等差异,海沟沉积物可能有不同的物质来源。因此,为进一步了解海沟深渊区的物质组成与来源,选取近陆的新不列颠海沟作为研究对象,通过分析其海底表层沉积物的地球化学特征,追踪新不列颠海沟不同水深与区域的沉积物来源。研究发现不论位于半深海、深海,乃至深渊区域,新不列颠"八字型"海沟的表层沉积物主要来自于周边岛屿的火山物质,但"八字型"海沟的西支和东支有差异,西支主要为新不列颠岛东部Rabaul火山和北部火山群及所罗门群岛的火山物质,其中在西支的最北站位新不列颠岛北部火山物质的比例最高。与西支相比,东支还受到了更多来源于TLTF(Tabar、Lihir、Tanga和Feni火山)火山链物质的影响,海沟东西支物源的差异与该地区复杂的洋流密切相关。此外,西支海沟轴部(最底端)站位更多来源于岛屿河流沉积物,受火山物质影响相对较小。 相似文献
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太平洋深海钻探和板块构造总结Г、Ｍ、ＢπａｃｏＢ沿着日本海沟、马里亚纳海沟和两条中美海沟的横剖面进行了深海钻探。对千岛－堪察加海沟、阿留申海沟、秘鲁－智利海沟和华盛顿－俄勒冈海沟则主要采用地震方法（多道地震探测等）进行了研究。在主要的太平洋海盆中打了... 相似文献
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俯冲带是地球上最大地震的发源地。俯冲板块正断层为海水进入上地幔,引起蛇纹石化提供通道,其地震可能引发大海啸。研究其动力学机制,对推动俯冲带动力学过程研究及保护人类生命安全都具有重要意义。本文综述了西太平洋汤加海沟、马里亚纳海沟、伊豆-小笠原海沟和日本海沟俯冲板块外缘隆起带到海沟附近的正断层分布与变形特征,定量化阐明了地球动力学模拟方法揭示的西太平洋俯冲板块正断层形成过程。研究发现汤加海沟和马里亚纳海沟的正断层平均断距最大;俯冲板片有效弹性厚度变化直接影响正断层形成区域,而有效弹性厚度与板块年龄相关性较大。本文系统性回顾了西太平洋俯冲动力学研究并且提出了对未来相关研究的启示。 相似文献
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在深水海洋管线的安装过程中,制造工艺的偏差和外部环境的影响易导致管线上不均匀的扭矩分布,在张力的共同作用下,管线在其触地区可能出现“成环”现象,受到严重损伤,而海洋管线的触地区也是海沟集中形成的区域。为了研究海沟对海洋管线成环行为的影响,基于OrcaFlex软件和构建海沟模型的经验公式,建立了深水悬链线立管和海沟的三维数值模型。就海沟轮廓、位置和土壤属性对立管成环行为的影响展开参数分析,并研究了不同工况下成环的临界载荷。研究表明：海沟的产生和扩展、立管相对海沟的合理位置以及土壤参数中海床表面不排水抗剪强度和吸力因子的增加,可有效降低立管成环过程中的最大压缩力和最大弯矩,从而减少成环引起的损伤;临界载荷的分析则有助于对成环的临界条件进行预测,避免成环现象的发生。 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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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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Phylogenetic diversity and phenotypic characterization of cultivable bacterioplankton isolated from polar oceans 总被引：1，自引：0，他引：1
A set of 27 marine planktonic bacteria isolated from the polar regions was characterized by 16S rDNA sequencing and physiological and biochemical testing. More than half of these bacteria were positive for caseinase, gelatinase and 13-glucosidase, and could utilize glucose, maltose or malic acid as carbon source for cell growth. Twelve isolates expressed nitrate reduction activities. Except for one antarctic isolate BSwlO175 belonging to Actinobacteria phylum, these isolates were classified as γ-Proteobacteria, suggesting that γ-Proteobacteria dominated in cultivable marine bacterioplankton at both poles. Genus Pseudoalteromonas was the predominant group in the Chukchi Sea and the Bering Sea, and genus ShewaneUa dominated in cultivable bacterioplankton in the Prydz Bay. With sequence similarities above 97%, genus Psychrobacter was found at both poles. These 27 isolates were psychrotolerant, and significant 16S rDNA sequence similarities were found not only between arctic and antarctic marine bacteria （ 〉 99% ）, but also between polar marine bacteria and bacteria from other aquatic environments （ ≥ 98.8% ）, including temperate ocean, deep sea, pond and lake, suggesting that in the polar oceans less temperature-sensitive bacteria may be cosmopolitan and have a bipolar, even global, distribution at the species level. 相似文献
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Oedometer tests have been carried out on 70 undisturbed surficial clays (at approximately 250 mm below the mudline), mostly collected by free-fall corers from sites widely scattered throughout the deep-sea North Atlantic. Acoustic measurements were also made, initially on contiguous samples and ultimately on the same sample using a geophysically instrumented oedometer which also collected electrical resistivity data. Apart from those quiescent areas below the carbonate compensation depth, such as north of the West Indies where very fine clays exist, most of the samples are silty clays whose geotechnical-geophysical properties are dependent on the type of clay minerals present (and their ability to take in moisture), the sand-size fraction, and the quantity of carbonate present. Thus the pure clays have high compressibilities which decrease on the addition of coarse particles, while the converse is true for the acoustic parameters, these increasing with the sand fraction. Using the notion of the intrinsic compression line for all samples, and comparison to it of the measured compression curves, it is clear that, contrary to some previously held ideas, most deep-sea clays are normally consolidated; the addition of carbonate has the effect of creating an open, stronger sediment skeleton. Interestingly, where information is available, the variation with depth of a sample's acoustic velocity follows the void ratio pressure relationship of the compression curve. This allows the construction of an in-situ sediment compression curve using the in-situ geophysical observations. 相似文献
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《海洋学报(英文版)》2014,(8):F0003-F0003
<正>Acta Oceanologica Sinica(AOS)is a comprehensive academic journal edited by the Editorial Committee of Acta Oceanologica Sinica and is designed to provide a forum for important research papers of the marine scientific community which reflect the information on a worldwide basis.The journal publishes scholarly papers on marine science and technology,including physics,chemistry,biology, 相似文献
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Nabil Sultan Pierre Cochonat Jean Fran ois Bourillet Florence Cayocca 《Marine Georesources & Geotechnology》2001,19(2):107-133
This article presents a methodology developed to evaluate the instability of submarine slopes that extend over a large area. Special attention was paid to (1) the complex geometry (bathymetry) and the expanse of the slope, (2) the heterogeneity of the sediment, and (3) the distribution of the pore pressure. The safety factor was considered as a spatially varying quantity. The General Formulation (GLE, Fredlund and Krahn 1977), which fully satisfies equilibrium conditions, was used for evaluating the stability of the marine slope. The submarine slope failure, which occurred on 16 October 1979 during the construction of the new Nice airport, was studied in order to test the developed model. Geotechnical parameters were taken from experimental tests carried out by IFREMER on 19 cores extracted at different depths (from 27 m to 1300 m) (Cochonat, Bourillet, and Savoye, 1993; Mulder et al., 1994). Many scenarios were proposed in order to explain the cause of the Nice slope failure (Habib, 1994). In this article, two of those scenarios were tested. Simulation results are presented and discussed. 相似文献