冲绳海槽北部表层沉积物中放射虫的分布与环境

对冲绳海槽北部80个表层沉积样品中放射虫进行的定量研究表明，其丰度和分异度西北部低，东南部高，由西北向东南递增；从西北陆架到东南海槽放射虫分布可分为陆架低值区，海槽边缘中值区和中央高值区，放射虫的组成以泡沫虫目占绝对优势，总体面貌为热带大洋暖水动物群，沉积物中放射虫的分布与现代表层海水温度，盐度的分布和变化趋势一致，但与营养盐和实级生产力的分布呈负相关关系；同时，放射虫的分布又与研究区的海流和水团有密切关系，其中黑潮对其有控制性影响，沉积物类型极大地影响着放射虫的分布，放射虫的丰度和分异度明显地随粒度的增大和陆源物质含量的增加而减小，此外，放射虫的分岂有此理也显示了与沉积物中火山物质含量的密切相关性。     

台湾东北部黑潮在流函数空间的水文分析

利用一种流函数投影方法对台湾东北部黑潮近20年的历史水文数据进行了诊断分析。结果表明,苏澳海脊北部位于冲绳海槽西南角的黑潮中层水的盐度明显高于周围海区;而位于1000m以下的冲绳海槽黑潮深层水相对于苏澳海脊以南的黑潮深层水具有高温低盐的特征,反映了苏澳海脊对黑潮水团的阻挡作用;位于300m以浅的冲绳海槽黑潮热带水相对于苏澳海脊以南的黑潮热带水具有低温低盐的特征。对冲绳海槽西南角黑潮中层水高盐中心的成因分析表明,除苏澳海脊的阻挡作用外,台湾东北部常年存在的气旋式冷涡与黑潮主体在陆架坡折交汇区的垂直混合过程也是需要考虑的物理因素。     

南海南部上层水体中多孔放射虫的组成与分布特征

通过对2002年5月采自南海南部11个站位的28个浮游分层拖网样品的定量研究,初步分析了南海南部上层水体中多孔放射虫的组成与分布特征。共鉴定出116属221种多孔放射虫,其中泡沫虫目123种,占总种数的55．7％;罩笼虫目98种,占总种数的44．3％。罩笼虫目在个体数量上占优势,罩笼虫目与泡沫虫目个体数量之比平均达1．73。多孔放射虫的属种组成呈现明显的热带暖水动物群的组合面貌,优势种相当突出,其组成与南海中北部海区及其它低纬度大洋相比存在一定差异,反映了南海南部海区独特的多孔放射虫属种组成特征。多孔放射虫丰度在不同水层中因受到不同环境因素的影响而呈现不同的平面分布趋势,惟一相似之处是高值多出现于西南或东北部海区;在垂直方向上基本呈随深度增加而减小的分布趋势,丰度和属种数最高值均出现于0—50m水层,在50m以深丰度和属种数均明显减少。各站位间简单分异度S变化幅度较大,在75—140种之间;而复合分异度H(s)变化幅度较小．在3．5-4．0之间。总体来说分异度值均比较高,表明南海南部上层水体中多孔放射虫种类多样性程度比较高,种群比较繁盛。     

1998年夏、冬季南海水团分析

为了解南海水团的特征和分布 ,基于 1 998年夏季和冬季两个航次的实测资料 ,采用聚类分析、判别分析和模糊分析方法 ,对南海的水团进行了分析。结果表明 ,南海外海水可划分为 6个水团 ,即南海表层水团、南海次表层水团、南海次 中层混合水团、南海中层水团、南海深层水团和南海底盆水。越南附近夏季存在一个暖涡 ;1 998年夏季还可鉴别出黑潮表层水团和黑潮次表层水团 ,但在冬季观测期间无黑潮水越过 1 1 9.5°E经线进入南海 ;这些现象可能与厄尔尼诺现象有关联。夏季有苏禄海海水在 5 0— 75m层经由民都洛海峡侵入南海     

冲绳海槽中部表层沉积物中的放射虫

1992年7月“向阳红16号”海洋调查船利用大洋50型抓斗在冲绳海槽中部（25°30’－30°N,125°－129°E）区域内获取表层沉积物样品88个。表层沉积物中的放射虫定量分析结果表明;愈近海槽放射虫的数量及属、种丰度值愈高,西侧槽坡离开槽区越远,放射虫数量及属种越渐少。而东侧槽被放射虫数量则表现了高、低值成点状分布的格局。表层沉积物中两大类放射虫的百分含量分别为泡沫虫约占87％,罩笼虫约占13％。另外根据分析结果,把本区分为3个小的沉积区：陆坡上部沉积区;陆被下部沉积区;海槽底部沉积区。     

夏季南海北部沙壳纤毛虫种类组成及空间分布

2007年8月夏季中国科学院南海海洋研究所南海北部开放航次期间,在北纬18°-22°,东经107°-122°范围内使用＂实验三号＂科考船进行了水体中沙壳纤毛虫的采样研究,探讨了沙壳纤毛虫的空间分布和种类组成。在36个站位中共鉴定出24属44种沙壳纤毛虫,其中优势种为长形旋口虫Helicostomella longa和根突拟铃虫Tintinnopsis radix,沙壳纤毛虫丰度变化范围为0–2200cell/L,平均丰度为221cell/L,从沿岸向外海方向,沙壳纤毛虫种类和丰度逐渐减少,其中A1站丰度最高（2200cell/L）,种类数最多（10）。夏季南海北部沙壳纤毛虫丰度与叶绿素a呈显著正相关,而与温度相关性不明显。夏季南海北部的上升流和珠江冲淡水携带的营养盐刺激了浮游植物的生长,影响着南海北部沙壳纤毛虫的种类组成和空间分布。     

冲绳海槽南部末次间冰期以来古海洋学变迁:ODP1202站的记录

对冲绳海槽南部ODP1202站165个沉积物样品进行了CaCO3含量测定和47个样品以浮游有孔虫为主的微体化石定量分析.应用CaCO3含量变化与δ18O曲线的对应关系,初步将1202站岩心划分为MIS 1-5期的沉积.根据浮游有孔虫中暖水、凉水、浅水和深水等生态组合丰度变化,推测冲绳海槽南部晚更新世末次间冰期以来,温跃层呈逐步加深和表层海水温度逐渐升高的趋势.MIS 5期以较浅温跃层和较低表层海水温度为特征,推测与研究区末次间冰期存在上升流有关.末次冰期(MIS 4-2期)时,Pulleniatina obliquiloculata在整个冲绳海槽中普遍以低丰度值出现,标志黑潮主流轴可能迁移出冲绳海槽.     

南沙群岛海区上层毛颚类的种类组成和丰度分布

根据南沙群岛海区1997年11月(秋季)、1999年4月(春季)和7月(夏季)3个航次的调查资料,对上层水域毛颚类的种类组成和丰度分布进行了分析。共鉴定毛颚类18种。秋、春、夏3个季节毛颚类平均丰度分别为(6.86±3.08)、(9.95±3.50)和(7.11±3.34)个/m3。肥胖软箭虫(Flaccisag-ittaenflata)、龙翼箭虫(Pterosagitta draco)和太平洋齿箭虫(Serratosagitta pacifica)是3个航次调查共有的优势种,肥胖软箭虫占绝对优势。调查海区毛颚类按其生态特征可分为暖水广布种、大洋性暖水种和暖水近岸种三个类群,前两者对毛颚类丰度分布起决定性作用。毛颚类丰度分布受东亚季风驱动的南海环流影响显著,在秋季东北季风期,毛颚类分布趋势为西高东低,高值区位于西南部,与海洋锋对应;在夏季西南季风期,毛颚类主要分布在西北部,与该区域存在的海洋锋和上升流密切相关。作为最主要的食物来源,桡足类丰度是影响南沙群岛海区毛颚类丰度变化的重要因素。     

夏季风爆发前后南沙海区上层水体中的现代放射虫

利用在南沙群岛及其邻近海域获取的2002和2004年两个春季航次的28个浮游拖网站位,分析了南海夏季风爆发前后南沙海区上层水体中的现代放射虫分布特征及其年际变化。研究结果显示,南沙海区春季两个航次放射虫属种组成以热带亚热带暖水种为主要优势种,但在主要属种组成及其丰度分布上具有明显的年际差异。上层水体中放射虫丰度以及主要属种相对丰度在夏季风爆发前后的分布变化也非常明显,表明南海上层水体中放射虫对夏季风爆发有响应;在夏季风爆发后放射虫总丰度明显增高,推测夏季风爆发后的海洋环境变化可能更有利于放射虫群的发育繁盛。但对造成放射虫在夏季风爆发前后分布差异特征的直接环境因素或其形成机制还有待深入分析。研究结果还进一步证实了T.octacantha和S.glacialis可以作为热带上升流的指示种。     

冲绳海槽南部末次间冰期以来古海洋学变迁：ODPI202站的记录

对冲绳海槽南部ODP1202站165个沉积物样品进行了CaCO3含量测定和47个样品以浮游有孔虫为主的微体化石定量分析。应用CaCO3含量变化与δ^18曲线的对应关系，初步将1202站岩心划分为MIS 1—5期的沉积。根据浮游有孔虫中暖水、凉水、浅水和深水等生态组合丰度变化，推测冲绳海槽南部晚更新世末次间冰期以来，温跃层呈逐步加深和表层海水温度逐渐升高的趋势。MIS5期以较浅温跃层和较低表层海水温度为特征，推测与研究区末次问冰期存在上升流有关。末次冰期(MIS4～2期)时，Pulleniatina obliquiloculata在整个冲绳海槽中普遍以低丰度值出现，标志黑潮主流轴可能迁移出冲绳海槽。     

南海西北部浮游生物中多孔放射虫的组成与分布

对南海西北部海区1959年全年各月所取得的浮游生物小网样品中的放射虫进行了定量研究,分析了其种类组成和分布,结果表明,所鉴定出的212种多孔放射虫主要为热带大洋暖水种,其中泡沫虫目(Spumellaria)145种,占总种数的68%,罩笼虫目(Nassellaria)67种,占总种数的32%;泡沫虫目无论在种类和数量上均较罩笼虫目占优势.研究海域的主要优势种为海绵球虫(Spongosphaera streptacantha)、钟翼盔虫(Pterocorys campanula)、四房面包虫四房亚种(Om-matartus tetrathalamus tetrathalamus)、三臂星虫(Triastrum aurivillii).该海域放射虫的全年密度分布状况变化很大,1,2月放射虫密度较小,分布范围也较小,3月起数量增多,4,5,6月是全年密度较大的月份,出现许多斑块状密集区,7,8月数量有所减少,其他月份密度也相对较小.放射虫数量变化总的趋势为春末夏初较多,秋季较少,冬季最少.放射虫的丰度和种类多样性在调查海域变化复杂,但基本趋势是从西北和北部向东南部由低逐渐升高;由海南岛周边海域和广东沿海向外海由低逐渐升高;此分布格局主要受海流、温度、盐度、深度和营养盐等环境因子的影响.     

Geochemical and isotopic characteristics of volcanic rocks from the northern East China Sea shelf margin and the Okinawa Trough

Volcanic rocks both from the northern East China Sea (NECS) shelf margin and the northern Okinawa Trough are subalkaline less aluminous,and lower in High Field Strength Elements (HFSE).These rocks are higher in Large Ion Lithophile Elements (LILE),thorium and uranium contents,positive lead anomalies,negative Nb-Ta anomalies,and enrichment in Light Rare Earth Elements (LREE).Basalts from the NECS shelf margin are akin to Indian Ocean Mid-Ocean Ridge Basalt (MORB),and rhyolites from the northern Okinawa Trough have the highest 207 Pb/ 204 Pb and 208 Pb/ 204 Pb ratios.The NECS shelf margin basalts have lower 87 Sr/ 86 Sr ratios,ε N d and σ 18 O than the northern Okinawa Trough silicic rocks.According to 40 K– 40 Ar isotopic ages of basalts from the NECS shelf margin,rifting of the Okinawa Trough may have been active since at least 3.65–3.86 Ma.The origin of the NECS shelf margin basalt can be explained by the interaction of melt derived from Indian Ocean MORB-like mantle with enriched subcontinental lithosphere.The basalts from both sides of the Okinawa Trough may have a similar origin during the initial rifting of the Okinawa Trough,and the formation of basaltic magmas closely relates to the thinning of continental crust.The source of the formation of the northern Okinawa Trough silicic rocks was different from that of the middle Okinawa Trough,which could have been generated by the interaction of basaltic melt with an enriched crustal component.From the Ryukyu island arc to East China,the Cenozoic basalts have apparently increasing trends of MgO contents and ratios of LREE to Heavy Rare Earth Elements (HREE),suggesting that the trace element variabilities of basalts may have been influenced by the subduction of the Philippine Sea plate,and that the effects of subduction of the Philippine Sea plate on the chemical composition of basaltic melts have had a decreasing effect from the Ryukyu island arc to East China.     

冲绳海槽构造活动的差异性及其非同步发展

冲绳海槽的地质和地球物理特征,特别是其构造活动性表明,海槽轴部存在一个扩张应力场,是弧后扩张形成的边缘盆地。其基本特征和构造活动性从东北至西南差别明显,具有南北分段的特点。据此作者把海槽分为扩张作用非同步发展的三段;东北段处在扩张前以裂陷为主的地堑或半地堑阶段;中段处于初始扩张过程的裂谷阶段;西南段则处于相对高级扩张的弧后盆地阶段。这种非同步发展可能是由于菲律宾海板块向亚洲大陆俯冲过程中,其速度在时间和空间上的差异性所致。     

Calcareous nannoplankton in the surface sediments of the East China Sea and its environmental implications

Calcareous nannoplankton flora in the surface sediments of the East China Sea has been investigated many times based on isolated sample collections since 1980. In the present study, 73 surface sediment samples recovered from the East China Sea, extending from the estuaries to the Okinawa Trough (about 10 -2000 m in depth of water), were chosen to investigate the floral distributional pattern and to discuss in greater detail the controlling factors. Thirty-nine species were identified under polarized microscope and SEM. In general, nannoplankton abundance and diversity increase progressively with the increase of depth. In estuaries and the inner shelf nannoplankton are extremely rare. The 50 m isobath is a sharp boundary for the development of calcareous nannoplankton. Another low floral concentration is encountered at the edge of the outer shelf where Pleistocene relict sediments outcrop. The nannoflora displays a scattered distributional pattern in the Okinawa Trough. Nannoplankton of larger sizes is m     

PN断面东海黑潮的地转经验模态分析

基于东海PN断面近50年的历史水文数据,本文中作者应用一种斜压流函数空间投影的方法分析冲绳海槽北部黑潮水团的季节性和年代际变异.诊断生成的地转经验模态(GEM)显示黑潮中层水的盐度在夏季相对较低,春季达到最高.通过比较1987年之后CTD数据生成的GEM场与1987年之前BOttle数据生成的GEM场,得以证实黑潮的年代际变化特征,即黑潮表层水近20年来温度升高而盐度减小,同时发现黑潮热带水具有盐度增加而中层水具有盐度减小的趋势.     

Temperature inversion in the Huanghai Sea bottom cold water in summer

Using conductivity-Temperature-depth data of a recent cruise during July 22-28, 2008 and historical data, it is found that temperature inversions occur from time to time in the Huanghai Sea(Yellow Sea) cold water mass (HSCWM) in summer. The temperature inversions are produced by the movement of the fresh and cold HSCWM masses above the warm and saline Huanghai Sea Warm Current water at the central bottom of the Huanghai Sea Trough. The non-homogeneous profiles of the temperature and the salinity suggest that vertical mixing in the HSCWM, which is of great importance to the circulation in the Huanghai Sea in summer, is weak. Trajectories of satellite-tracked surface drifters suggest that waters in the northern reach of the Huanghai Sea move southward along the 40-50 m isobaths and descend into the southern Huanghai Sea to form the western core of the HSCWM.     

Petrologic perspectives on tectonic evolution of a nascent basin (Okinawa Trough) behind Ryukyu Arc：A review

Okinawa Trough is a back-arc, initial marginal sea basin, located behind the Ryukyu Arc–Trench System. The formation and evolution of the Okinawa Trough is intimately related to the subduction process of the Philippine Sea Plate beneath the Eurasian Plate since the late Miocene. The tectonic evolution of the trough is similar to other active back-arcs, such as the Mariana Trough and southern Lau Basin, all of which are experiencing the initial rifting and subsequent spreading process. This study reviews all petrologic and geochemical data of mafic volcanic lavas from the Okinawa Trough, Ryukyu Arc, and Philippine Sea Plate, combined with geophysical data to indicate the relationship between the subduction sources(input) and arc or back-arc magmas(output) in the Philippine Sea Plate–Ryukyu Arc–Okinawa Trough system(PROS). The results obtained showed that several components were variably involved in the petrogenesis of the Okinawa Trough lavas: sub-continental lithospheric mantle underlying the Eurasian Plate, Indian mid-oceanic ridge basalt(MORB)-type mantle, and Pacific MORB-type mantle. The addition of shallow aqueous fluids and deep hydrous melts from subducted components with the characteristics of Indian MORB-type mantle into the mantle source of lavas variably modifies the primitive mantle wedge beneath the Ryukyu and subcontinental lithospheric mantle(SCLM) beneath the Okinawa Trough. In the northeastern end of the trough and arc, instead of Indian MORB-type mantle, Pacific MORB-type mantle dominates the magma source. Along the strike of the Ryukyu Arc and Okinawa Trough, the systematic variations in trace element ratios and isotopic compositions reflect the first-order effect of variable subduction input on the magma source. In general, petrologic data, combined with geophysical data, imply that the Okinawa Trough is experiencing the "seafloor spreading" process in the southwest segment, "rift propagation" process in the middle segment, and "crustal extension" process in the northeast segment, and a nascent ocean basin occurs in the southwest segment.     

冲绳海槽南部表层沉积中的浮游有孔虫及其地质意义

对冲绳海槽南部53个表层沉积样品中大于0.154mm的浮游有孔虫进行系统鉴定和定量统计,并采用Q型因子分析,求得浮游有孔虫各属种和组合的分布特征:N.Dutertei－p.Obliquiloculata组合主要分布在离大陆和台湾岛较近的地方,而G.Glutinata－G.Ruber组合则主要分布在冲绳海槽的中央及靠琉球岛的一侧,且发现浮游有孔虫丰度、属种组合和碎壳率等的分布和变化主要受控于水深、碳酸盐溶跃层、温跃层以及水团等各类环境因子.