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排序方式: 共有75条查询结果,搜索用时 31 毫秒
1.
Observational study of the circulation in the southern South China Sea   总被引:2,自引:0,他引:2  
CTD data from two oceanographic survey cruises, conducted by “Shiyan No. 3” R/V during two reversing monsoons, were employed to calculate and analyze the distributions of temperature, salinity and geopotential anomaly in the southern South China Sea (SSCS). Based on these distributions, the horizontal structures of the SSCS circulation are described systematically. Study results show that the SSCS circulation structure could be classified as a two-layer (the upper and the lower) pattern, and that the main circulation in the upper layer (0–400 m) is driven by the South China Sea monsoons and is opposite in direction to the reversal of the monsoons. The distributions of principal current systems and their features are presented. Two important local phenomena, local eddy and oceanic front, were observed.  相似文献   
2.
洋壳向陆壳下俯冲是板块运动的一种基本形式,用数理方法研究它有助于深刻认识它的运动机制。考虑了地质体的流变性质,推导并建立了洋壳向陆壳下俯冲的流变学数学模型。  相似文献   
3.
深海泥的矿物组成及其物化性能研究   总被引:3,自引:0,他引:3  
采用化学分析、X射线衍射、差热和热重分析、粒度与比表面积分析等技术、方法对5个我国南海深海泥样品进行了研究.结果表明,不同区域的深海泥中,其矿物组成有显著的差异,其中粘土矿物、石英、碳酸盐为主要的结晶相矿物;同时,非晶质粘土矿物广泛发育.深海泥中的矿物质具有粒径小、比表面积大、粘土矿物结晶程度差等特点,因此具有较好的活性.深海泥将是一种巨大的潜在非金属矿产资源.  相似文献   
4.
Three new species of misophrioid copepods are described from anchialine habitats on oceanic islands. Expansophria galapagensis n.sp. is described from two localities on Santa Cruz, Galapagos Islands, Speleophria campaneri n.sp. from Ngamduk Cave, Angaur Island, Palau and S. scottodicarloi n.sp. from Chalk Cave on Bermuda.  相似文献   
5.
Five taxa of talitrid amphipods were found in the archipelago of Bermuda, of which three were recorded there for the first time. Four of these are supralittoral wrack generalists: Platorchestia monodi BOLD:AAB3402, (a unique Molecular Operational Taxonomic Unit according to the Barcode Index Number system), a related species recognized by molecular methods, Platorchestia platensis BOLD:AAA2949, Mexorchestia carpenteri carpenteri BOLD:AAC1491 and Tethorchestia antillensis; and one a terrestrial leaf-litter generalist: Talitroides alluaudi. A key is provided to discriminate between the formally described talitrids of Bermuda. Dispersal mechanisms from the American continent to Bermuda were considered for all taxa based on species distributions along the North American Atlantic coast and also investigated by molecular methods, using genetic population differentiation and haplotype network analysis based on the barcode region of cytochrome c oxidase subunit I gene. For P. monodi BOLD:AAB3402 the genetic results suggest that some dispersal events occurred before human colonization of Bermuda but are equivocal about the source population and therefore the direction of dispersal. Some very recent synanthropic dispersal is possible with this species. For the other two species studied genetically, P. platensis BOLD:AAA2949 and M. c. carpenteri BOLD:AAC1491, the small population samples analysed support dispersal to Bermuda from the American mainland, before human occupation of Bermuda, although the available sample size was limited for these species. The available limited direct, non-genetic evidence supports synanthropic transport for Talitroides alluaudi. Platorchestia monodi BOLD:AAB3402 is found in the same wrack habitat as P. platensis BOLD:AAA2949 on Bermuda, apparently without interbreeding. No evidence was found that driftwood specialist talitrids had become established in Bermuda.  相似文献   
6.
藏北改则-色哇缝合带的蛇绿岩,与特罗多斯、岛湾的蛇绿岩剖面对比,区别是厚度小和缺乏席状岩墙。该区的变质超镁铁岩属阿尔卑斯橄榄岩-蛇纹岩组合,其化学成分与玄武岩互补,说明玄武岩浆系地幔岩分熔的产物。  相似文献   
7.
FZF3—1型海洋智能信息浮标系统的研制   总被引:1,自引:0,他引:1  
采用性能优良、高可靠性低功耗的PC/104组成了数据采集处理系统,并针对国内外传感器的特点,设计出一系列硬件接口电路。通过卫星通信系统,将浮标所在站位的水文、气象资料等数据发送到地面接收站,提高了测量数据的可信度及浮标的在位安全性。  相似文献   
8.
运用野外地质填图、岩石地球化学分析以及同位素年龄等方法探讨冀北赤城红旗营子杂岩的岩石组合、构造属性、变质演化以及时代归属等特征,为重新划分冀北赤城的红旗营子群提供依据。结果显示红旗营子杂岩由云州表壳岩及其内部的退变榴辉岩、蛇纹岩(蛇纹石化方辉橄榄岩)和蛇纹石化(橄榄)大理岩等透镜状构造岩块组成,它们一起经历了晚古生代(321~326 Ma B.P.)区域角闪岩相变质事件。其中,云州表壳岩的岩性主要为石榴黑云斜长片麻岩,原岩是形成于大陆岛弧环境的泥质(含泥质)砂岩,沉积作用发生在晚古生代(340~369Ma B.P.),属于晚古生代沉积-变质地层;石榴黑云斜长片麻岩之中的退变榴辉岩、蛇纹岩(蛇纹石化方辉橄榄岩)和蛇纹石化(橄榄)大理岩等构造岩块应属"外来"的洋壳残片,成因上可能与古亚洲洋的洋壳向南俯冲消减有关。赤城红旗营子杂岩的岩石组合、构造属性、变质演化以及同位素地质年代学等特征明显不同于冀北其他地区的红旗营子群,冀北红旗营子群需要重新划分。  相似文献   
9.
This study aims to examine spatial and temporal variations of zooplankton species composition, density and biomass distribution and community structure, based on the data obtained from three separate cruises carded out in November 1997, April and July 1999. Results show that 244 species of zooplankton and 8 groups of planktonic larvae were identified, which were dominated by copepods, followed by amphipods, ostracods and medusae. The total species were 201 and 198 for the cruises of November 1997 and July 1999, respectively, and no obvious seasonal variation of species richness was observed. The distribution of zooplankton species richness decreased from pelagic to coastal waters. Average richness of species in each station was higher in the cruises of November 1997(62) and April 1999(61) than in the cruise in July 1999 (56), which was mainly a result from the pelagic or coastal water mass movement made by the monsoon. Zooplankton in the upper waters (0--100 m) around Nansha Islands belonged to the typical tropic pelagic fauna, most of them were pelagic warm-water species, followed by coastal warm-water species and euryhaline warm-water species. The number of dominant species ranged from 5 to 7 in each cruise. No obvious seasonal succession of dominant species was ob- served. Sagitta enflata, Cypridina narni, Cosmocalanus darwinii, Pleuromamma gracilis and Echino-pluteus larva were the main dominant species. The average of zooplankton biomass and density in three cruises were 31, 32, 28 mg·m^-3 and 31, 39, 35 ind·m^-3, respectively. Copepods were the most abundant, followed by chaetognaths. Zooplankton high biomass distributed mainly in the northwestern waters around Nansha Islands, and generally occurred in the areas of oceanic front and upweUing. The main reason for zooplankton quantity without obvious seasonal variation was the relative steady temperature dynamics in the waters around Nansha Islands.  相似文献   
10.
 依据大洋钻探井及地震剖面资料,定量确定南海同扩张期和后扩张期深海盆沉积充填差异及沉积物来源变化。研究显示,南海深海盆自渐新世(32 Ma)开始形成,随着南海二次扩张海盆范围逐渐扩大,海盆内主要充填火山碎屑角砾岩及火山灰,碳酸盐岩、超微化石软泥,泥质粘土、粉砂质粘土、泥岩及粉细砂岩。深海盆充填主要沉积物为晚中新世(11.6Ma)以来的陆源碎屑沉积,丰富陆源碎屑的供给与南海闭合过程中同期区域构造事件(如青藏高原快速隆升、菲律宾板块俯冲)密切相关,也与晚中新世以来东亚季风增强以及源区强烈的风化剥蚀有关。  相似文献   
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