南海北部渐新世末的构造事件   总被引：3，自引：2，他引：1  

邵磊  庞雄  张功成  乔培军  李前裕  韦刚健  吴梦霜 《地球科学》2009,34(5):717-724

ODP1148站以及珠江口盆地沉积物均记录了渐新世末发生的重大地质构造事件, 这一构造事件在时间上与南海扩张轴发生跳跃的时间十分吻合, 是渐新世以来南海构造演化史上最为重大的构造事件, 涉及到南海扩张、盆地类型转化、沉积物源变迁等一系列相关联的重大地质事件.伴随这一地质构造事件, 南海北部沉积物成分发生剧烈改变, 出现渐新世-中新世地球化学成分上的跳跃, 在深海沉积中发生沉积间断及滑塌事件, 并使珠江口盆地由断陷型盆地转为坳陷型盆地, 白云凹陷由渐新世晚期的浅水陆架环境转为中新世以后的深水陆坡环境.可以认为, 这次构造运动奠定了我国现代的地理格局, 也标志着我国东部陆相盆地最佳烃源岩形成期的结束, 在南海乃至东亚地区影响深远.   相似文献   

南海西北陆缘多金属结核地球化学特征及成因     

张振国  方念乔  杜远生  高莲凤  杨胜雄  刘坚  宋城兵 《地球科学》2009,34(6):955-962

对取自南海西北陆缘海域的大型多金属结核进行了电子探针、X射线粉晶衍射(XRD)、等离子质谱仪(ICP-MS) 和等离子光谱仪(ICP-AES) 等方面的分析.结核核心部位的主要矿物组成为石英、伊利石、钠长石和绿泥石, 壳层的主要矿物为δMnO₂等.铁、锰组分呈现Fe含量高、Mn含量低和Mn/Fe低的特征.Si含量高, Cu、Co、Ni含量低; 稀土元素(REE) 含量高, 平均为1472.30×10-6, 轻稀土与重稀土的比值(LREE/HREE) 达19.54, 并且存在较强的Ce正异常.元素含量的变化显示: 从结核内壳层到外壳层, Fe、Mn、Cu、Co等元素含量呈不规律变化, 具有典型的边缘海特征, 该特征反映结核在形成过程中受到边缘海沉积环境波动变化的影响, 陆源物质供应量的增加对Fe、REE、Si等元素的富集起到了促进作用, 而对Mn、Ca等元素的富集则产生明显的稀释作用.多金属结核Mn/Fe比及Mn-Fe- (Cu+Ni) ×10三组分图解显示, 南海北部陆缘多金属结核为水成成因, 该成因与结核所赋存的边缘海环境密切相关, 反映了结核成长发育的过程中, 南海典型的边缘海沉积条件和多变的古海洋环境因素对其产生了重要影响.   相似文献   

SEDIMENT LOAD AND ITS INFLUENCE ON CHANNEL PROCESSES OF SOME LARGE RIVERS IN RUSSIA AND CHINA~1     

LIU Shuguang  CHALOV R.S  WU Dandan  LI Congxian Postdoctor  Research Fellow  Key Laboratory of Marine Geology  Tongji University  Shanghai  China & Researcher  State Key Laboratory of Estuarine  Coastal Research  Shanghai  China Professo 《国际泥沙研究》2000,(3)

I INTRODUCTIONThe volume and regime of sediment load are the most important factors, which are responsible for theformation, direction and deformation rate of the river channels. Despite the long history of study anddevelopment of sediment load calculation methodology, there are still numerous problems that remain tobe solved such as river pattern and sediment movement and so on (Wang et al, 1997).In this respect, the comparative analysis of sediment load and river channel processes of la…  相似文献   

Lateral stirring of large-scale tracer fields by altimetry     

Guillaume Dencausse  Rosemary Morrow  Marine Rogé  Sara Fleury 《Ocean Dynamics》2014,64(1):61-78

Ocean surface fronts and filaments have a strong impact on the global ocean circulation and biogeochemistry. Surface Lagrangian advection with time-evolving altimetric geostrophic velocities can be used to simulate the submesoscale front and filament structures in large-scale tracer fields. We study this technique in the Southern Ocean region south of Tasmania, a domain marked by strong meso- to submesoscale features such as the fronts of the Antarctic Circumpolar Current (ACC). Starting with large-scale surface tracer fields that we stir with altimetric velocities, we determine ‘advected’ fields which compare well with high-resolution in situ or satellite tracer data. We find that fine scales are best represented in a statistical sense after an optimal advection time of ～2 weeks, with enhanced signatures of the ACC fronts and better spectral energy. The technique works best in moderate to high EKE regions where lateral advection dominates. This technique may be used to infer the distribution of unresolved small scales in any physical or biogeochemical surface tracer that is dominated by lateral advection. Submesoscale dynamics also impact the subsurface of the ocean, and the Lagrangian advection at depth shows promising results. Finally, we show that climatological tracer fields computed from the advected large-scale fields display improved fine-scale mean features, such as the ACC fronts, which can be useful in the context of ocean modelling.  相似文献   

Cloning,characterization,and expression analysis of the DEAD-box family genes,Fc-vasa and Fc-PL10a,in Chinese shrimp (Fenneropenaeus chinensis)     

周倩如  邵明瑜  秦贞奎  康庆浩  张志峰 《中国海洋湖沼学报》2010,(1)

RNA helicases of the DEAD-box and related families are involved in various cellular processes including DNA replication,DNA repair,and RNA processing.However,the function of DEAD-box proteins in aquaculture species is poorly understood at molecular level.We obtained the full-length cDNA sequences of two genes encoding helicase-related proteins,Fc-vasa and Fc-PL10a,from the testes of Chinese shrimp,Fenneropenaeus chinensis.The two predicted amino acid sequences contain all the conserved motifs characterized ...  相似文献   

Distribution and expression in vitro and in vivo of DNA vaccine against lymphocystis disease virus in Japanese flounder(Paralichthys olivaceus)   总被引：1，自引：0，他引：1  

郑风荣  孙修勤  刘洪展  吴兴安  钟楠  王波  周国栋 《中国海洋湖沼学报》2010,(1)

Lymphocystis disease,caused by the lymphocystis disease virus (LCDV),is a significant worldwide problem in fish industry causing substantial economic losses.In this study,we aimed to develop the DNA vaccine against LCDV,using DNA vaccination technology.We evaluated plasmid pEGFP-N2-LCDV1.3 kb as a DNA vaccine candidate.The plasmid DNA was transiently expressed after liposome transfection into the eukaryotic COS 7 cell line.The distribution and expression of the DNA vaccine (pEGFP-N2-LCDV1.3kb) were also ana...  相似文献   

Model‐based evaluation of impact of soil redistribution on soil organic carbon stocks in a temperate hedgerow landscape          下载免费PDF全文

Marine Lacoste  Valérie Viaud  Didier Michot  Christian Walter 《地球表面变化过程与地形》2016,41(11):1536-1549

Agroforestry systems are promoted for providing a number of ecosystem services and environmental benefits, including soil protection and carbon sequestration. This study proposes a modelling approach to quantify the impact of soil redistribution on soil organic carbon (SOC) storage in a temperate hedgerow landscape. Evolution of SOC stocks at the landscape scale was examined by simulating vertical and horizontal SOC transfers in the 0–105 cm soil layer due to soil redistribution by tillage and water processes. A spatially explicit SOC dynamics model (adapted from RothC‐26.3) was used, coupled with a soil‐redistribution model (LandSoil). SOC dynamics were simulated over 90 years in an agricultural hedgerow landscape dedicated to dairy farming, with a mix of cropping and grasslands. Climate and land use were simulated considering business‐as‐usual scenarios derived from existing information on the study area. A net decrease in SOC stocks was predicted at the end of the simulation period. Soil redistribution induced a net SOC loss equivalent to 2 kg C ha^?1 yr^?1 because of soil exportation out of the study site and an increase in SOC mineralization. Hedgerows and woods were the only land use in which soil redistribution induced net SOC storage. Soil tillage was the main process that induced soil redistribution within cultivated fields. Soil exportation out of the study area was due to erosion by water, but remained low because of the protective role of the hedgerow network. These soil transfers redistributed SOC stocks in the landscape, mostly within cultivated fields. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

Elemental and isotopic compositions of the hydrothermal sulfide on the East Pacific Rise near 13°N     

ZENG ZhiGang  CHEN DaiGeng    YIN XueBo  WANG XiaoYuan  ZHANG GuoLiang  & WANG XiaoMei  Seafloor Hydrothermal Activity Laboratory of the Key Laboratory of Marine Geology  Environment 《中国科学:地球科学(英文版)》2010,(2)

The mineralogical,elemental,and isotopic characteristics of a hydrothermal sulfide sample from one dredge station (12°42.30'N,103°54.48'W,water depth 2655 m) on the East Pacific Rise near 13°N were analyzed.The hydrothermal sulfide was composed mainly of sphalerite,chalcopyrite,and pyrite and was a Zn-rich sulfide;in layer ep-s-1,goethite formed by secondary oxidation was found.The concentrations of rare elements,such as Li (0.15×10-6-0.30×10-6),Be (0.01×10-6-0.05×10-6),Zr (73.8×10-9-1344×10-9),Nb (8.14×10-9-64.7×10-9),Hf (2.54×10-9-28.0×10-9),and Ta (0.203×10-9-1.21×10-9),were far lower in the hydrothermal sulfide than in the ocean crust,whereas the content of Au was higher and the contents of Co,Ni,Sr,Cs,Ba,Bi,and U were low.The correlations between Zn and Cr,Cd and Ga,Cu and P,P and In (R2 0.8) were positive,whereas those between Zn and Fe,Cu,and Ba (R2 0.8) were distinctly negative.From low-temperature mineral assemblages to high-temperature mineral assemblages,the spatial distributions of dispersive and rare elements (e.g.In,Li,Cs) in the hydrothermal sulfide displayed corresponding variations.The variations observed in some elements (e.g.,Cd,Cs,P) are controlled by Zn,Fe,and Cu sulfides,respectively.Seafloor weathering accounts for the enrichment of V,Mn,and rare earth elements (REE) in the henna sulfide-oxidation layer that bears the secondary oxide mineral,leading to identical REE patterns for this layer (ep-s-1) and seawater.Seafloor weathering also distinctly affects the correlations between the element ratios of the hydrothermal sulfide.From high-temperature mineral assemblages to low-temperature mineral assemblages,Fe content and δ 34S value of the hydrothermal sulfide increase gradually,and Zn content and lead isotopic ratios decrease gradually on the contrary,which indicate the influences of seawater on elements and the sulfur and lead isotopic compositions enhance gradually during the formation of hydrothermal sulfides.  相似文献   

Impacts of the Nakhodka heavy-oil spill on an intertidal ecosystem: an approach to impact evaluation using geographical information system     

Teruhisa K  Masahiro N  Hiroshi K  Tomoko Y  Kouichi O;Marine Life Research Group of Takeno 《Marine pollution bulletin》2003,47(1-6):99-104

A major heavy-oil spill from the Russian tanker Nakhodka occurred in the Sea of Japan on 2 January 1997. We investigated the impacts of this spill on a rocky intertidal ecosystem along the southern coast of the Sea of Japan. We selected Imago-Ura Cove as our study site to observe temporal changes along the oiled shore, because minimal cleaning effort was made in this area. Field surveys were conducted every autumn and spring from 1997 to 2000. We measured coverage by macroalgae in 1 x 1-m(2) quadrats and counted the animals in 5 x 5-m(2) quadrats along the intertidal zone. Changes in the ecosystem caused by the oil spill were analyzed by applying a geographical information system (GIS) to the Sea of Japan for the first time. The GIS showed that following the accident there were heavily oiled areas in sheltered regions, but these decreased over the three years. It also showed that coverage by macroalgae and the number of animals increased, although some species of algae with microscopic sporophyte generations, and some populations of perennial shellfish, remained stable or decreased during the study period. GIS was able to trace temporal changes in intertidal communities resulting from the impacts of heavy oil on flora and fauna at a spatial scale of 10-100 m. GIS is thus a practical tool for visualizing, analyzing, and monitoring changes in an ecosystem polluted by oil, taking into account topographic differences along the coastline.  相似文献   

New British unmanned submersible will slash underwater inspection costs     

Marine Unit Technology Ltd. 《Ocean Engineering》1979,6(3):341-343

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