南海北部含油气构造上方化探异常研究

在南海北部利用地球化学方法作为油气勘探的一种辅助手段。在6个航次中采集了沉积物、底层海水及海面大气样品，测定了近50种化探指标，并采用稳健统计方法进行了数据处理和异常圈定。化探结果在油气藏上方发现了清晰的、具不同指标组合的综合化探异常，与邻近空构造形成鲜明的对照。圈闭顶部的块状异常和圈闭周绿的环状、半环状异常是下伏油气藏的良好指示，而剖面上呈锯齿状、平面上呈线状的异常则与断裂带有关。实践表明，建立已知油气藏上方的化探异常模式及解剖已知空构造上方的地球化学特征对于指导本区或邻区的化探异常评价是十分必要的。     

A Zonal Pathway for NADW in the South Atlantic

Several large deployments of neutrally buoyant floats took place within the Antarctic Intermediate (AAIW), North Atlantic Deep Water (NADW), and the Antarctic Bottom Water (AABW) of the South Atlantic in the 1990s and a number of hydrographic sections were occupied as well. Here we use the spatially and temporally averaged velocities measured by these floats, combined with the hydrographic section data and various estimates of regional current transports from moored current meter arrays, to determine the circulation of the three major subthermocline water masses in a zonal strip across the South Atlantic between the latitudes of 19°S and 30°S. We concentrate on this region because the historical literature suggests that it is where the Deep Western Boundary Current containing NADW bifurcates. In support of this notion, we find that a net of about 5 Sv. of the 15–20 Sv that crosses 19°S does continue zonally eastward at least as far as the Mid-Atlantic Ridge. Once across the ridge it takes a circuit to the north along the ridge flanks before returning to the south in the eastern half of the Angola Basin. The data suggest that the NADW then continues on into the Indian Ocean. This scheme is discussed in the context of distributions of dissolved oxygen, silicate and salinity. In spite of the many float-years of data that were collected in the region a surprising result is that their impact on the computed solutions is quite modest. Although the focus is on the NADW we also discuss the circulation for the AAIW and AABW layers.     

Palynological Evidence on Climate Changes in the East China Sea During Mid and Late Holocene

The pollen analysis of DGKS9617 core in the East China Sea (covering about the last 6800 years) shows five obvious pollen assemblages and seven sub-assemblages. Combined with the sediment and the result of diatom analysis, the climate changes are reconstructed during the Middle and Late Holocene. Corresponding to the pollen assemblages, the climate shifts just as follows: Assemblage Ⅰ-Warm and Dry Stage, Assemblage Ⅱ-Cool and Humid Stage, Assemblage Ⅲ-Hot and Dry Stage (the mean annual temperature is 2～3 ℃ higher than that today ), Assemblage Ⅳ-Cool and Humid Stage, Assemblage Ⅴ-Wann and Dry Stage. The third stage is divided into three substages i.e. a slight colder and dry one, a slight wanner and humid one and a slight warmer and dry one. During the fifth stage, the climate becomes similar to that today with three warm substages and two cool substages.     

夏季东海西部表层海水中的pCO2及海-气界面通量

根据2001年夏季长江口及东海西部海域表层海水pCO     

东海温度锋的分布特征及其季节变异

根据１９３４－１９８８年东海水文观测资料，重点分析东海温度锋的分布特征及其季节变异，并结合近期中日黑潮合作调查研究成果，初步探讨温度锋季节变异和水团演变的关系，所得主要结论是：（１）东海不仅常年存在浙闽沿岸锋，东海北部陆架锋和黑潮锋，而且、春、夏两季，在东海南部还出现一条东海中部出架锋。（２）江海温度锋季节变化的特点是：冬季，锋的宽度和强度皆是表层最强，夏季，表层温度锋仅出现在浙江近岸小范围海域。     

Sea surface temperature variations in the southwestern South China Sea over the past 160 ka

Sea surface temperatures (SSTs) in the southwestern South China Sea have been reconstructed for the past 160 ka using the Uk37 paleothermometer from the core MD01-2392. The temperature differences between glacial times (MISs 6 and 2) and interglacial times (MISs 5.5 and 1) are 2.2~2.5 ℃. Younger Dryas event during the last deglaciation was documented in both the planktonic foraminiferal δ18O and SST records. After MIS 5.5, SSTs displayed a progressive cooling from 28.6 to 24.5 ℃, culminating at the LGM. During this gradual cooling period, warm events such as MISs 5.3, 5.1 and 3 were also clearly documented. By comparison of SST between the study core and Core 17954, a pattern of low or no meridional SST gradients during the interglacial periods and high meridional SST gradients during the glacial periods was exhibited. This pattern indicates the much stronger East Asian winter monsoon at the glacial than at the interglacial periods. Spectral analysis gives two prominent cycles: 41 and 23 ka, with the former more pronounced, suggesting that SSTs in the southern SCS varied in concert with high-latitude processes through the connection of East Asian winter monsoon.     

Spatio-temporal variability of small copepods (especially Oithona plumifera) in shallow nearshore waters off the south coast of South Africa

Although small copepods are one of the main dietary sources for many commercially important fish, their role in the pelagic trophic dynamics has traditionally been underestimated due to the methodology commonly used in plankton sampling. Temporal variation in abundance of adults and nauplii of small copepods (particularly Oithona plumifera) in nearshore waters on the south coast of South Africa was investigated fortnightly over 14 months at site (km) and location (100 m) scales. Sampling was within <500 m of the shore, where depth was ca. 10 m, using vertical hauls of an 80-μm mesh plankton net from 1 m above the seabed to the surface. Twenty-seven adult copepod taxa were recorded, but Oithona spp. was consistently the most abundant. Taxon richness was 7–19 on each sampling occasion. There was strong temporal variation (Oithona varied between 0 and 2300 m⁻³), but much of this was short-term variability (e.g. between consecutive sampling sessions), with no seasonality or other long-term discernable patterns. There were periods of consistently low numbers, but very high numbers often followed samples with low abundances. Nor was there spatial structure at the location scale, though numbers differed between sites. Despite considerable variability at the location scale within sites, Kenton consistently showed higher densities than High Rocks. Separate analyses, with Bonferroni adjustment, showed that this difference was significant on eight out of 21 occasions for Oithona, six for other pelagic copepods and three for nauplii. This suggests that hydrodynamics favour aggregation of plankton at Kenton. A high degree of short-term variability, with a tendency for aggregation of small zooplankton at certain sites has implications for both pelagic processes and food-web links between the benthic and pelagic environments.     

Intrusion of Kuroshio water onto the continental shelf of the East China Sea

As a fundamental study to evaluate the contribution of the Kuroshio to primary production in the East China Sea (ECS), we investigated the seasonal pattern of the intrusion from the Kuroshio onto the continental shelf of the ECS and the behavior of the intruded Kuroshio water, using the RIAM Ocean Model (RIAMOM). The total intruded volume transport across the 200m isobath line was evaluated as 2.74 Sv in winter and 2.47 Sv in summer, while the intruded transport below 80m was estimated to be 1.32 Sv in winter and 1.64 Sv in summer. Passive tracer experiments revealed that the main intrusion from the Kuroshio to the shelf area of the ECS, shallower than 80m, takes place through the lower layer northeast of Taiwan in summer, with a volume transport of 0.19 Sv. Comparative studies show several components affecting the intrusion of the Kuroshio across the 200 m isobath line. The Kuroshio water intruded less onto the shelf compared with a case without consideration of tide-induced bottom friction, especially northeast of Taiwan. The variations of the transport from the Taiwan Strait and the east of Taiwan have considerable effects on the intrusion of the Kuroshio onto the shelf.     

晚中生代─新生代南海周缘地块运动与南海演化

报道了由华南几个盆地的古地磁数据综合而得的反映该区白垩纪以来古纬度变化曲线，结合Ｓｃｈｍｉｄｔｋｅ等（１９９０）发表的加里曼丹１５０Ｍａ以来的古地磁数据，表明华南与加里曼丹在４０Ｍａ前具有大致相同的古纬度变化史，差异仅出现在距今３０Ｍａ前后和１０Ｍａ以来。若此趋势可靠，则可作出下列推断：（１）南海的扩张只能发生在距今３０Ｍａ附近或１０Ｍａ以后华南与加里曼丹反向运动时期；距今３０Ｍａ的扩张已被广为接受；（２）华南与加里曼丹之向可能存在的古南海只能在９１Ｍａ之前存在；（３）南海演化可能存在两期扩张。南海的拟合可通过沿３５００ｍ等深线的先道时针旋转、后北向平移两个步骤完成。这与Ｈａｙａｓｈｉｄａ等（１９９１）提出的日本海张开与扩张模式很相似，提示东亚边缘海的形成和演化可能具有同样的机制。华南距今５０Ｍａ以来的古纬度变化与Ｔａｐｐｏｎｎｉｅｒ（１９８２）的传播挤出构造模式所预期的基本吻合，表明距今５０Ｍａ以来华南古纬度变化的运动学机制可用Ｔａｐｐｏｎｎｉｅｒ模式作解释。     

南海南部约30 ka来沉积有机质的生物输入特征

对位于南沙海区的1962柱状样中的有机质进行了热解色谱分析，估算了沉积有机质中水生生物输入和陆源生物输入的变化情况，得出了两种输入的高分辨率的堆积速率曲线，并依此探讨了有关的古海洋事件。发现Younger Dryas、Heinrich及Bond周期事件在本海区皆有表现，说明“西太平洋暖池”在末次冰期是不稳定的。