马里亚纳海槽玄武岩岩石学

马里亚纳海槽岩石学的研究表明本区岩石属基性的玄武岩,又细分为洋底玄武岩(OFB)和钙碱玄武岩(CAB)。微量元素相对球粒陨石标准化数值特征:除了Sc、Ti,V外,其它过渡元素都有亏损,Cr、Ni出现了明显负异常,Ti相对较富集,稀土元素(REE)表现富集型的型式;同位素测试结果,εNd(0)=6.9。可以认为这些玄武岩是上幔岩的局部熔融形成的岩浆沿着扩张中心喷溢到海底,而形成的新生洋壳。     

冲绳海槽沉积物干酪根特征

本文采用元素分析、镜下观察、红外光谱、扫描电镜和热解分析等技术,分析了冲绳海槽柱状样中腐植酸、富里酸和干酪根的化学、物理特征,并探讨了它们之间的成因关系和干酪根类型。沉积物的产烃能力甚差,每吨沉积物仅能生成0.49～1.18kg烃类物质。     

Aluminum in the East China Sea and Okinawa Trough, marginal sea areas of the Western North Pacific

The distribution of aluminum (Al) in seawater has been investigated in the continental slope and the Okinawa Trough areas of the East China Sea, which is one of the marginal seas in the western North Pacific Ocean. Aluminum concentration in waters over the slope and the Trough ranged from 5.6 to 25 nmol/kg in the surface layer (0–100 m), and had a minima of 1.1 nmol/kg between 400 and 500 m depth and ranged from 1.3 to 9.7 nmol/kg in the deep or bottom waters. Aluminum values were higher than in the surface waters of the central North Pacific, while minimum values were similar to levels in the intermediate or deep waters of the central North Pacific, except for the bottom water over the slope. This suggests that the high Al concentration in the surface reflects the large atmospheric input of Asian dust around the western side of the North Pacific region. On the continental slope, Al concentrations in the upper 500 m depth decreased slopeward. This horizontal gradient of Al can be explained from the combination of dilution by upwelling of Al-poor water originated from the North Pacific Intermediate Water (NPIW) which intrudes into the mid-depth of the Okinawa Trough and the scavenging of Al by biogenic particles in the continental slope zone.     

南冲绳海槽地震反射波特征及其地质解释

对南冲绳海槽进行反射地震调查 ,结果表明 :(1 )海槽盖层主要由反射层组 (时代相当于第四纪 )和反射层组 (时代相当于上新世 )组成 ,推测槽底局部存在中新统。槽底沉积物主要源自中国大陆。轴部目前仍处在裂陷作用阶段 ;(2 )断裂极为发育 ,可分 NE— SW向(西南端转为近 E— W向 )和 NW— SE向两组 ,分别属张性及张扭性断裂 ,后者切割前者 ;(3)岩浆活动十分强烈 ,东南缘岩浆活动尤甚 ,推测其岩性以中、基性岩为主     

贝类育苗中几种水处理新方法应用的探讨

本文主要叙述磁化水、泡沫处理水、臭氧处理水、高分子重金属离子吸附剂在贝类育苗上的应用，介绍其使用方法、优点和不足，从而为贝类人工育苗创造出一个良好的水环境，使贝类育苗稳产高产。     

发震带试验(SEIZE)

对发震带试验计划(SEIZE)以及南海（Nankai）海槽的发震带钻探计划（NanTroSEIZE）进行了综述。SEIZE作为大陆边缘计划(MARGINS)的重要研究内容和综合大洋钻探计划（IODP）的优先研究领域,重点对世界主要俯冲发震带进行研究。SEIZE的主要研究内容包括：①凸凹体的物理性质;②在地震周期里,应力、应变和孔隙流体成分随时间的变化;③在俯冲逆冲断层上,发震带上界和下界的确定;④引起海啸的发震带的特征;⑤大型逆冲带地震在物质转换过程中所起的作用。NanTroSEIZE将成为IODP第一个基于立管钻探的计划,也是科学大洋钻探历史上第一个分期实施的复合钻探计划;钻入发震带的复合钻探计划将最终验证关于发震带的各种假说。      

冲绳海槽中南部及其邻近陆架悬浮体的分布、组成和影响因子分析

初夏冲绳海槽中南部海域悬浮体含量的分布特点为:表层水体中部海区高,南北海区低;中底层水体自南西至北东由低至高.从陆架到海槽断面的悬浮体含量分布为陆架最高值区、陆坡最低值区和海槽低值区.悬浮体组成包括矿物岩石碎屑、生物骨屑以及絮凝体.矿物岩石碎屑主要分布在陆架区中、下层水体,生物骨屑主要分布在海槽区(整个水层)和陆架区上层水体,絮凝体在研究区都有分布.海槽区与陆架区的悬浮体含量垂直分布和组分特征具有明显的差异.研究区悬浮体分布和组成主要受控于黑潮对陆架物质向冲绳海槽输送的阻隔、生物生产量以及地形、地理环境.     

冲绳海槽北部柱状沉积物中有机质地球化学特征——对热液活动的指示

通过气相色谱-质谱联用仪(GC-MS),分析了冲绳海槽北部柱状沉积物中有机质的分布和组成特征。样品中正烷烃显示出明显的双峰分布,其中高分子正烷烃显示出明显的奇数碳优势;低分子的正烷烃显示出偶数碳优势,其丰度最大值位于C16和C18处。该柱状沉积物中120～140cm层样品(样品S10-7)中沥青、正烷烃以及脂肪酸的含量都要远高于其他层位样品,且该层位样品中正十八烷酸质量比(16.915μg/g)要高于其他层位样品1～2个数量级。S10-7样品中3个成熟度参数也高于其他样品,预示该层位样品受到明显的热蚀变。S10-7样品中有机质的分布和组成情况预示该柱状沉积物样品周围可能存在未被发现的热液区。本研究旨在揭示该柱状沉积物中有机质的来源,同时评估该区热液活动的可能性。本研究的开展可为该区沉积物中有机质来源及热液活动研究提供研究基础和依据。     

Combining 2D-basin and structural modelling to constrain heat transport along the Muroto Transect,Nankai Trough,Japan

The Nankai Trough located southeast of Shikoku Island, Japan, exhibits a zone of exceptionally high heat flow. In the central part of the Nankai Trough the fossil spreading centre of the Shikoku Basin is subducted beneath the southwest Japan arc. We have modelled the temperature and maturation history along the Muroto Transect reaching from the tip of the thrust zone out into nearly undeformed Quaternary and Tertiary sediments seawards of Nankai Trough. We used two balanced cross-sections defining the sections before and after overthrusting as input for 2D-basin modelling. We can show that rapid burial and overthrusting during the Quaternary in combination with a heat flow history following the cooling curve of a 15 Ma old oceanic plate is not sufficient to explain the measured maturity of organic material in the sediments. Several heat flow scenarios derived from theoretical concepts [Yamano, M., Kinoshita, M., Goto, S., Matsubayashi, O., 2003. Extremely high heat flow anomaly in the middle part of the Nankai Trough. Physics and Chemistry of the Earth, Parts A/B/C 28, 487–497.] and previous modelling approaches [e.g. Brown, K.M., Saffer, D.M., Bekins, B.A., 2001. Smectite diagenesis, pore water freshening, and fluid flow at the toe of the Nankai wedge. Earth and Planetary Science Letters 194, 97–109; Spinelli, G.A., Underwood, M.B., 2005. Modeling thermal history of subducting crust in Nankai Trough: constraints from in situ sediment temperature and diagenetic reaction progress. Geophysical Research Letters 32(L09301): doi:10.1029/2005GL022793; Steurer, J., Underwood, M.B., 2003. Clay mineralogy of mudstones from the Nankai Trough reference sites 1173 and 1177 and frontal accretionary prism site 1174. In: H. Mikada et al. (Eds.), pp. 1–37. Available from: <http://www-odp.tamu.edu/publications/190196SR/VOLUME/CHAPTERS/211.PDF>] were tested. The best match between observed maturity levels, temperature and heat flow measurements is reached for a heat flow history which initially assumes the cooling of a 15 Ma old oceanic lithosphere but is reheated to 170–180 mW/m² during the phase of rapid burial in the Quaternary. This can be achieved either by assuming the onset of hydrothermal circulation in the cooling crust or by reheating caused by off-axis volcanism at about 6 Ma [Yamano, M., Kinoshita, M., Goto, S., Matsubayashi, O., 2003. Extremely high heat flow anomaly in the middle part of the Nankai Trough. Physics and Chemistry of the Earth, Parts A/B/C 28, 487–497.].