Linear magnetic anomalies and tectonic development of the middle Okinawa Trough     

Liang Ruicai  Wu Jinlong  Liu Baohu  Wang Yong  Wang Shugong 《海洋学报(英文版)》2001,20(1):105-116

ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅＯｋｉｎａｗａＴｒｏｕｇｈ (ＯＴ) ,ｌｏｃａｔｅｄｎｏｒｔｈｗｅｓｔｏｆｔｈｅＲｙｕｋｙｕＴｒｅｎｃｈａｎｄｔｈｅＲｙｕｋｙｕｇｕｎｔｏ ,ｅａｓｔｏｆｔｈｅＥａｓｔＣｈｉｎａＳｅａｓｈｅｌｆ,ｉｓａｂａｃｋ ａｒｃｂａｓｉｎｂｕｌｇｅｄｔｏｔｈｅＲｙｕｋｙｕＴｒｅｎｃｈ .ＴｈｅＯＴｅｘｔｅｎｄｓｆｒｏｍＫｙｕｓｈｕｉｎｔｈｅｓｏｕｔｈｗｅｓｔｏｆＪａｐａｎｔｏｔｈｅＩｌａｎＰｌａｉｎｉｎｔｈｅｎｏｒｔｈｅａｓｔｅｒｎＴａｉｗａｎ ,Ｃｈｉｎａｉｎｔｈｅｓｏｕｔｈｗｅｓｔ…  相似文献   

Glass inclusions in volcanic rocks in the Okinawa Trough back-arc basin:constraints on magma genesis and evolution   总被引：1，自引：0，他引：1  

Yu Zenghui  Zhai Shikui  Li Xianzhong 《海洋学报(英文版)》2001,20(3):383-390

INTROOUcr1ONThe Okinawa Trough is a typical marginal back-arc basin, where its oPening began in rela-tively recent years* There is a great controversy about the origin of its initial magYna. haltand acid volcanic pumice make up the bimedal volcanism in the Okinawa Trough. MOSt of geol-ogists believed that the acid pumice was the preduct of extremely crystal fractionation of baseltInagTna, but the others argued that it should com from the melting of lower-crust. Som de-tailed petrolOgic…  相似文献   

Seasonal and Spatial Variations of Total Mass Flux around Coral Reefs in the Southern Ryukyus,Japan     

Mohamed?IsmailEmail author  Tadashi?Kimura  Yumiko?Suzuki  Makoto?Tsuchiya 《Journal of Oceanography》2005,61(3):631-644

Total mass flux, size distribution of sediment particles and some chemical components such as total carbon (TC), total nitrogen (TN) and calcium carbonate (CaCO₃) were monitored monthly using a multi-cup sediment traps at seven coral reef sites (6 reef flat and 1 reef slope) of the Marine Protected Areas around Ishigaki, Kohama, Kuroshima and Iriomote Islands in the southern Ryukyus, Japan from September 2000 to September 2001. The size distribution of trapped sediments revealed mostly uni-modal fine sand to mud in the reef flat and gravelly to coarse sand in the reef slope. The total mass flux ranged between 0.54 to 872 gm⁻²d⁻¹, and showed a pronounced seasonality (high in summer-autumn and low in spring) at each site, which was consistent with the rainfall and typhoon regime. Exceptionally high values were observed on the reef slope (Iriomote) in February–March 2001 (1533 gm⁻²d⁻¹) owing to a large amount of bottom sediment re-suspension. On the reef flat (Todoroki South and North; Ishigaki), values obtained in July–August 2001 (872 gm⁻²d⁻¹) and August–September 2001 (800 gm^{− 2}d⁻¹) indicate the high terrestrial discharge from Todoroki River. Trapped sediment particles consist of CaCO₃ (1.2–27.1%) and a non-carbonate fraction (98.8–72.9%), which contains total carbon (4.9–26%), carbonate carbon (CO₂-C) (0.2–3.1%) and non-carbonate carbon (NC-C) (7.9–25.6%). Total nitrogen content was in the range 0.02–0.48%. TN is contained mainly in the carbonate fraction and NC-C may be contained in the non-carbonate fraction. The low TN/OC ratio of the trapped sediments suggests that they were mostly of terrestrial origin and that both fractions migrated. The high total mass flux derived from Todoroki River exceeded the threshold at which a lethal effect on coral community is caused. The results stress the importance of conducting seasonal studies of sedimentation over more than one year and at more than one location in south Japan coral reef ecosystems to gain an understanding of the processes controlling the total mass fluxes and their nutrients content, also to develop an awareness of how to prevent the damage of coral reef ecosystems and, if it does occur, to allow mitigation measures to be undertaken.  相似文献   

ODP与冲绳海槽海底热水活动研究   总被引：2，自引：1，他引：2  

高爱国 《海洋科学》1996,20(3):25-30

本文简要介绍了ＯＤＰ与海底热水活动研究，冲绳海槽中部现代海底热水活动区热水活动研究简况及其热水活动特征；就冲绳海槽中部热水活动研究中存在的问题与ＯＤＰ在冲绳海槽热水区钻探的科学目标进行了讨论。  相似文献   

Is there a connection between high transport of water through the Rockall Trough and ecological changes in the North Sea?   总被引：1，自引：1，他引：1  

Holliday  N. Penny; Reid  Philip C. 《ICES Journal of Marine Science》2001,58(1):270-274

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冲绳海槽海底地形的补偿模式初步研究   总被引：1，自引：1，他引：1  

刘保华  刘忠臣 《海洋地质与第四纪地质》1998,18(4):29-34

从区域补偿模式和实验均衡理论出发,利用重力和地形资料计算了冲绳海槽的均衡响应函数,结果表明：冲绳海槽南段弹性板有效厚度和补偿深度明显大于中段,结合其它地质地球物理资料解释认为,产生这种差异的原因主要是南,中两段岩石圈温度和补偿机制的不同所致。  相似文献   

Microbial Diversity in Nankai Trough Sediments at a Depth of 3,843 m   总被引：6，自引：0，他引：6  

Lina Li  Jean Guenzennec  Peter Nichols  Pierre Henry  Miki Yanagibayashi  Chiaki Kato 《Journal of Oceanography》1999,55(5):635-642

Dense populations of bivalves, primarily Calyptogena sp., were observed at cold seeps of the Nankai Trough. Bacterial input to the sediment was estimated through determination of phospholipid ester-linked fatty acid (PLFA) and DNA profiles. Results indicated a bacterial biomass of 10⁹ cells (g dry wt)^-1 while individual fatty acid profiles revealed a predominance of monounsaturated fatty acids, mainly 18:1 isomers. The presence of these fatty acids can be interpreted to reflect a response to low temperature and a predominance of psychrophilic bacteria. DNA fragments encoding bacterial ribosomal RNA small-subunit sequences (16S rDNA) were amplified by the polymerase chain reaction method using DNA extracted directly from the sediment samples. From the sequencing results, at least 19 kinds of bacterial 16S rDNAs related to mostly the Proteobacteria and a few gram-positive bacteria were identified. These results suggest that the bacterial community in the Nankai Trough sediments consists of mainly bacteria belonging to the Proteobacteria , , and subdivisions. Bacteria belonging to the and subdivisions, which are known to include epibiont and sulfate reducing bacteria, respectively, were mostly detected in the sediment obtained from inside the area of the Calyptogena community, and the -Proteobacteria may function to supply reduced sulfur to bacterial endosymbionts of Calyptogena.  相似文献   

标志沉积层磁组构特征及其古环境意义研究     

丛友滋  张家强 《海洋地质与第四纪地质》1997,17(3):31-36

通过对长江三角洲及其邻近区域埋藏古土壤、潮坪、长江下游河道浸滩、舟山滨岸风成沙丘、南京黄土古土壤序列沉积体的磁组构测量统计分析，取得了各自的标志特征。该２特征揭示出，舟山滨岸风成沙丘与南京黄土吉土壤序列沉积的搬运介质能量位相基本一致，其物源来向却显示出巨大差异；上述两类沉积体与上述现今潮坪、河道漫滩沉积体地搬运介质能量位相及物源来向均显示出绝然不同的标志特征。然而浸滩物源来民南京黄土的物尖兵为向却  相似文献   

南海西沙海槽地区的海底热流测量   总被引：20，自引：0，他引：20  

徐行  施小斌  罗贤虎  刘方兰  郭兴伟  沙志斌  杨小秋 《海洋地质与第四纪地质》2006,26(4):51-58

为了解南海西沙海槽区的地热特征,利用Ewing型地热探针在该区开展了地热测量,并利用TK04热导率仪测量了相关站位表层沉积物样品的热导率,获得了7个站位的热流数据。结果表明,研究区7个站位的热导率变化范围为0.88~1.06 W/m.K,平均为0.96 W/m.K,地温梯度变化范围为85~120℃/km,热流值变化范围为83~112 mW/m2,平均达到95 mW/m2。分析表明测量结果与20世纪80年代中美合作在西沙海槽的地热测量结果一致性较好,说明研究区仍具有高热流特征,推测高热流特征可能与本区高热背景、莫霍面埋深较浅、断裂发育、晚期岩浆活动和基底起伏等有关。  相似文献   

日本海岸工程研究进展——第52回日本海岸工学讲演会介绍     

郑金海 《海洋工程》2006,24(2):139-142

介绍了日本第52回海岸工学讲演会的概况,从海岸灾害、海岸生态环境、波浪与水流、海岸泥沙运动与地形变化、海岸建筑物等5个方面综述了日本海岸工程研究的进展情况。  相似文献