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1.
South China Sea 总被引：8，自引：0，他引：8
The South China Sea is poorly understood in terms of its marine biota, ecology and the human impacts upon it. What is known is most often contained in reports and workshop and conference documents that are not available to the wider scientific community. The South China Sea has an area of some 3.3 million km2 and depths range from the shallowest coastal fringe to 5377 m in the Manila Trench. It is also studded with numerous islets, atolls and reefs many of which are just awash at low tide. It is largely confined within the Tropic of Cancer and, therefore, experiences a monsoonal climate being influenced by the Southwest Monsoon in summer and the Northeast Monsoon in winter. The South China Sea is a marginal sea and, therefore, largely surrounded by land. Countries that have a major influence on and claims to the sea include China, Malaysia, the Philippines and Vietnam, although Thailand, Indonesia and Taiwan have some too. The coastal fringes of the South China Sea are home to about 270 million people that have had some of the fastest developing and most vibrant economies on the globe. Consequently, anthropogenic impacts, such as over-exploitation of resources and pollution, are anticipated to be huge although, in reality, relatively little is known about them. The Indo-West Pacific biogeographic province, at the centre of which the South China Sea lies, is probably the world's most diverse shallow-water marine area. Of three major nearshore habitat types, i.e., coral reefs, mangroves and seagrasses, 45 mangrove species out of a global total of 51, most of the currently recognised 70 coral genera and 20 of 50 known seagrass species have been recorded from the South China Sea. The island groups of the South China Sea are all disputed and sovereignty is claimed over them by a number of countries. Conflicts have in recent decades arisen over them because of perceived national rights. It is perhaps because of this that so little research has been undertaken on the South China Sea. What data are available, however, and if Hong Kong is used, as it is herein, as an indicator of what the perturbations of other regional cities upon the South China Sea are like, then it is impacted grossly and an ecological disaster has probably already, but unknowingly, happened. 相似文献
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基于华南及周边地区106个宽频带地震台站多年记录的MS≥5.0中浅源地震事件,开展瑞利面波层析成像和速度结构特征研究,获得了华南大陆及南海北部地区10~100s瑞利波群速度分布图像和典型剖面下方地壳上地幔速度结构,为理解该地区构造演化和深部过程提供约束.考虑到实际地震射线的覆盖情况以及华南地区主要构造的主体展布特征,本文同时采用传统的规则网格剖分和平行主要构造走向的非规则网格剖分方法,分别进行分格频散反演,开展了不同参数化方案对反演结果影响的对比分析研究.基于瑞利面波层析成像结果,进行了典型剖面横波速度结构反演,重建了华南地区由内陆至南海海域主要构造单元的壳幔横波速度结构.研究结果表明,扬子和华夏块体地壳上地幔结构特征差异显著,扬子块体地壳和岩石圈厚度均大于华夏地块,且扬子块体上地幔顶部速度较华夏块体低,岩石圈厚度在雪峰山造山带下方发生过渡和转换;南海北部陆缘和南海海盆上地幔速度较高且形态相对完整,表现为非火山型大陆边缘和已停止扩张海盆的壳幔结构特征. 相似文献
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根据中国南方地温梯度和大地热流的数据各418个,编制了中国南方地温梯度图和中国南方大地热流图,研究了中国南方现今地温梯度分布特征和大地热流分布特征.结果显示,中国南方地温梯度介于782～1625℃/km,平均241℃/km;大地热流变化于22～220 mW/m2之间,平均值为642 mW/m2.东南沿海和滇西南地区为高地温梯度分布区,扬子地块为中－低温地温梯度区.地温梯度不仅与区域热构造背景有关,还显著地受地下水热活动、断裂以及地层热导率影响.中国南方大地热流东部、西南部高,中部低,且异常高值点主要沿板块边界缝合带、深大断裂活动带分布.大地热流与区域构造运动、最后一次热事件发生的时间、岩石圈拉张程度、地壳厚度、壳内高导层埋深等因素具有明显的相关性. 相似文献
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South China karst aquifer storm-scale hydrochemistry 总被引：7，自引：0，他引：7
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L. Liu 《Pure and Applied Geophysics》2001,158(9-10):1583-1611
— This paper reviews some remarkable characteristics of earthquakes in a Stable Continental Region (SCR) of the South China Block (SCB). The kernel of the SCB is the Yangtze platform solidified in late Proterozoic time, with continental growth to the southeast by a series of fold belts in Paleozoic time. The facts that the deviatoric stress is low, the orientations of the major tectonic features in the SCB are substantially normal to the maximum horizontal principal stress, and a relatively uniform crust, seem to be the major reasons for lack of significant seismicity in most regions of the SCB. Earthquakes in this region are mainly associated with three seismic zones: (1) the Southeast China Coast seismic zone related to Guangdong-Fujian coastal folding belt (associated with Eurasia-Philippine Sea plate collision); (2) the Southern Yellow Sea seismic zone associated with continental shelf rifts and basins; and (3) the Downstream Yangtze River seismic zone spatially coinciding with Tertiary rifts and basin development. All three seismic zones are close to one or two major economic and population centers in the SCB so that they pose significant seismic hazards. Earthquake focal mechanisms in the SCB are consistent with strike-slip to normal faulting stress regimes. Because of the global and national economic significance of the SCB and its dense population, the seismic hazard of the region is of outstanding importance. Comparing the SCB with another less developed region, a pending earthquake with the same size and tectonic setting would cause substantially more severe social and economic losses in the SCB. This paper also compiles an inventory of historic moderate to great earthquakes in the SCB; most of the data are not widely available in English literature. 相似文献
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Succession of Cambrian conodonts from South China 总被引：1，自引：0，他引：1
Dong Xiping 《中国科学D辑(英文版)》2000,43(3):3
More than 4200 kg, the total weight, of 980 productive conodont samples mainly from four key sections in western Hunan and northwestern Hunan, South China have been processed. It is found that the paraconodonts occurring below Fengshanian (upper Upper Cambrian) may be used for stratigraphic subdivision and correlation. Accordingly, eight conodont zones ranging from upper Middle Cambrian to upper Upper Cambrian in South China are erected for the first time. The correlation between these zones and those of North China, North America and Iran is discussed. These eight zones are in ascending order as follows:Gapparodus bisulcatus-Westergaardodina brevidens zone, Shandongodus priscus-Hunano- gnathus tricuspidatus zone, Westergaardodina quadrata zone, Westergaardodina matsushitai-W. grandidens zone, Westergaardodina proligula zone, Westergaardodina cf. behrae-Prooneotodus rotundatus zone, Proconodontus zone, Cordylodus proavus zone. 相似文献
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ZHAN Renbin RONG Jiayu CHENG Jinhui & CHEN Pengfei Nanjing Institute of Geology Palaeontology Chinese Academy of Sciences State Key Laboratory of Palaeobiology Stratigraphy Nanjing China 《中国科学D辑(英文版)》2005,48(5):662-675
Since the recognition of the Cambrian Evolutionary Fauna, Paleozoic Evolutionary Fauna and Modern Evolutionary Fauna[1—3], more and more paleontolo-gists have paid attention to the great Ordovician bio-diversification event which was critical to the forma-tion of the Paleozoic Evolutionary Fauna, and during which the marine organisms experienced one of the most profound evolutionary radiations of the Phan-erozoic[4]. Three biodiversity maxima have been rec-ognized on a global scale[5] wi… 相似文献
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Measurement of228Ra activities in the upper 300 m water column was conducted at two stations in the South China Sea using an MnO2-fiber extraction/β-counting technique of228Ac. Results showed that228Ra activities ranged from 0.38 to 3.60 Bq · m-3. The vertical profiles of228Ra at the time-series station favored a steady state assumption. Based on a one-dimensional steady state model,228Ra-nitrate coupled approach was applied to stations NS97-43, NS99-53 (T1), NS99-53 (T2). New production thus quantified were 4.4, 5.1 and 5.7 mmolC · m-2 · d-1, respectively,f ratios in the South China Sea were estimated from the derived new production and the documented primary productivity in the
regime, to be 0.12–0.15. 相似文献
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Tectonics of South China continent and its implications 总被引：36，自引：0，他引：36
ZHANG GuoWei GUO AnLin WANG YueJun LI SanZhong DONG YunPeng LIU ShaoFeng HE DengFa CHENG ShunYou LU RuKui YAO AnPing 《中国科学:地球科学(英文版)》2013,56(11):1804-1828
This paper aims at exploring the tectonic characteristics of the South China Continent(SCC)and extracting the universal tectonic rules from these characteristics,to help enrich the plate tectonic theory and better understand the continental dynamic system.For this purpose,here we conduct a multi-disciplinary investigation and combine it with the previous studies to reassess the tectonics and evolution of SCC and propose that the tectonic framework of the continent comprises two blocks,three types of tectonic units,four deformation systems,and four evolutionary stages with distinctive mechanism and tectonic characteristics since the Neoproterozoic.The four evolutionary stages are:(1)The amalgamation and break-up of the Neoproterozoic plates,typically the intracontinental rifting.(2)The early Paleozoic and Mesozoic intracontinental orogeny confined by plate tectonics,forming two composite tectonic domains.(3)The parallel operation of the Yangtze cratonization and intracontinental orogeny,and multi-phase reactivation of the Yangtze craton.(4)The association and differentiation evolution of plate tectonics and intracontinental tectonics,and the dynamic characteristics under the Meso-Cenozoic modern global plate tectonic regime. 相似文献
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南海地震与海啸 总被引：3，自引：0，他引：3
地震海啸的形成要具备3个条件:一是有深海盆地,可以容纳巨量海水;二是海底地形隆起与拗陷反差强烈;三是存在倾滑型活断层,可发生6级以上倾滑型的地震。查南海及其周边地形地貌,北西南三面都有宽阔的大陆架,中部又是平坦的深海平原,都不具备发生地震海啸的条件,惟独东侧马尼拉海沟才具备产生地震海啸的条件。南海地壳属于大洋型地壳与大陆型地壳之间的过度类型。其断裂构造非常发育,不同地段具有明显差异。北部为拉张型,南部为挤压型,西部为剪切型,东部为俯冲型,中部是扩张型。按断裂展布方向可分为NE向、NW向、EW向、SN向4组;按断裂切割深度,可分为岩石圈断裂、地壳断裂、基底断裂和盖层断裂。这些断裂多数为活动断裂,而东缘俯冲型断裂又是发震断裂。从地震分布、震源机制解分析,南海北、西、南以及中部都不具备引发地震海啸的条件,只有台南—菲律宾地震带东西两侧的贝尼奥夫带发生的倾滑型或具倾滑分量的走滑型6级以上地震,才有可能引发海啸,并可能对南海及我国东南沿海诸省以及港澳地区产生影响。 相似文献
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华南中生代地球动力学机制研究进展 总被引：4，自引：0，他引：4
华南中生代地质的最重要特征是大规模的构造变形、大面积的火成岩出露及爆发式的成矿作用.不同学者基于不同的研究就华南中生代演化动力学机制提出了多种观点及模式,其对华南动力学演化的一些关键问题尚存争议,目前并无公认的模式.本文在总结大量前人研究基础上,对目前已有的华南中生代构造及岩浆作用的动力学机制进行了综述,认为大洋板片俯冲模式及多板块相互作用模式可以兼顾解释华南中生代的构造变形及岩浆作用,相对于其他模式具有一定优势.针对已有的概念模型,可通过数值模拟将复杂地质过程定量化,对其开展可证明的检验,并综合构造变形、岩浆活动等实际观测数据对中生代华南的深部动力学机制做更深入的探讨.多学科交叉可以为华南动力学研究提供全面的视野,是今后的发展方向. 相似文献
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Proposed new Lower Triassic stages in South China 总被引：5，自引：1，他引：5
As the global Lower Triassic stages are not properly defined, a Chinese scheme of the Lower Triassic subdivision was recently
proposed to meet the insistent need of the general investigation in China. The Lower Triassic sequences of South China are
briefly summarized and the twofold Lower Triassic subdivision is discussed. The type sections of the two Chinese Lower Triassic
stages, Yinkengian and Chaohuan, and their definitions are stated. 相似文献
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Teleconnection between ENSO and climate in South China 总被引：2，自引：1，他引：1
Qinglan Li Ji Chen 《Stochastic Environmental Research and Risk Assessment (SERRA)》2014,28(4):927-941
This study investigates the features of the teleconnection between El Niño–Southern Oscillation (ENSO) and the climate over the region with the latitude from 21°N to 25°N and longitude from 111°E to 116°E in South China for the period from 1960 to 2005. The climate variables analyzed are the monthly means of daily maximum temperature (Tmax), minimum temperature (Tmin), precipitation and relative humidity (RH), which are recorded at 20 weather stations over the region. The cross correlation coefficients between the ENSO index and those climate variable anomalies are calculated to evaluate the strength of the teleconnection. The analysis results reveal that ENSO has positive influence on most of the climate variables in the study region. Specifically, ENSO has significant effects on Tmin (but not Tmax) with the corresponding time delay of about 4 months. In addition, ENSO has considerable influence on precipitation and RH over the study region with teleconnection lag time of around 2 and 1 month, respectively. 相似文献
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《中国科学:地球科学(英文版)》2015,(3)
The South China Sea where water depth is up to 5000 m is the most promising oil and gas exploration area in China in the future.The seismic data acquired in the South China Sea contain various types of multiples that need to be removed before imaging can be developed.However,compared with the conventional reflection migration,multiples carry more information of the underground structure that helps provide better subsurface imaging.This paper presents a method to modify the conventional reverse time migration so that multiple reflections can migrate to their correct locations in the subsurface.This approach replaces the numerical impulsive source with the recorded data including primaries and multiples on the surface,and replaces the recorded primary reflection data with multiples.In the reverse time migration process,multiples recorded on the surface are extrapolated backward in time to each depth level,while primaries and multiples recorded on the surface are extrapolated forward in time to the same depth levels.By matching the difference between the primary and multiple images using an objective function,this algorithm improves the primary resultant image.Synthetic tests on Sigsbee2 B show that the proposed method can obtain a greater range and better underground illumination.Images of deep water in the South China Sea are obtained using multiples and their matching with primaries.They demonstrate that multiples can make up for the reflection illumination and the migration of multiples is an important research direction in the future. 相似文献
16.
基于2009~2010年国家、区域测震台网的387个宽频带台站数据,通过互相关方法提取到可靠的瑞利波经验格林函数,利用相位匹配滤波时频分析技术测量瑞利波相速度频散曲线,最后采用噪声层析成像方法获得了华南地区不同周期的瑞利波相速度分布图。结果显示,华南地区速度结构横向变化幅度较小,反映了华南地区作为一个整体较为稳定,与华南地区自晚中生代以来未发生过强烈构造活动的特征基本一致;虽然华南地区整个岩石圈速度结构较为均匀,但扬子块体西部、四川盆地与扬子块体东部、华夏块体间存在明显的速度差异,体现在周期为8~10s时华夏块体相速度大于扬子块体西部、川滇块体以及四川盆地,由于沉积层较厚四川盆地速度最低;周期为10~30s时华夏块体面波相速度大于扬子块体西部和四川盆地,而川滇块体速度最低;周期为35s时扬子块体、华夏块体、四川盆地的速度基本一致,且高于川滇块体,这与华南地区地壳厚度明显小于川滇块体的特征相符。 相似文献
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