东海西湖凹陷平北地区表层沉积物特征及其成因初探

对研究区域的３７０个站位,１０８４个样品进行了粒度分析,对其中的部分样品进行了重矿物、古生物的分析和鉴定,发现东海西湖凹陷平片地区表层改造砂的特征与一般的规律有较大的差别,这种独特的表层沉积物特征的形成原因主要和所处的地貌部位有关。     

Paleo- to Eoarchean crustal evolution in eastern Hebei,North China Craton: New evidence from SHRIMP U–Pb dating and in-situ Hf isotopic study of detrital zircons from paragneisses

In the Caozhuang complex in eastern Hebei, North China Craton, the Paleo- to Eoarchean crustal evolution was earlier revealed by the preservation of detrital zircon grains older than (or as old as) 3.8 Ga in fuchsite-quartzite. In order to test if the Eoarchean antiquity is also preserved in rocks other than the fuchsite quartzite, we collected two paragneisses, a hornblende gneiss and a garnet–biotite gneiss, from Huangbaiyu village and dated their detrital zircon grains. The zircon dating of the hornblende gneiss yielded concordant ²⁰⁷Pb/²⁰⁶Pb ages ranging from 3684 to 3354 Ma. However, an older date of 3782 Ma with 18% discordancy was also obtained. Detrital zircon grains from the garnet–biotite gneiss gave a similar ²⁰⁷Pb/²⁰⁶Pb age range, from 3838 to 3342 Ma. The metamorphic domains of the zircon grains from both samples, including the strongly recrystallized cores and rims, recorded an overprinting metamorphism at ca. 2.5 Ga, which correlates with the most widespread tectono-thermal event in the North China Craton. In situ zircon Hf-isotope analyses on the dated zircon grains yielded a wide range of model ages (T_DM1) from 4.0 to 3.3 Ga with corresponding ε_Hf(T) from −36.0 to +4.8. This suggests that the evolution of the crustal segment in this area has involved multiple phases of juvenile crustal addition as well as recycling of older crustal rocks. The new geochronological results imply the presence of a significant amount of Eoarchean crustal fragments in the eastern Hebei area. The sedimentary protoliths of the paragneisses and other high-grade metamorphic rocks in the Caozhuang complex were probably deposited between 3.4 and 2.5 Ga.     

东海表层水体中的多环芳烃及其沉积通量估算

以东海陆架水体中溶解态多环芳烃(PAHs)含量为基础,引入颗粒相-水相间的物质吸附系数(Koc)计算悬浮颗粒物中PAHs有机碳归一化含量,结合陆架沉积物有机碳的年埋藏通量,估算东海陆架沉积物中PAHs沉积通量。结果显示:水体中溶解态的15种PAHs总含量为(701±392)ng/L,变化范围为412~1 032ng/L,PAHs组成以3环为主。计算得到的悬浮颗粒物中15种PAHs有机碳归一化含量为20~28μg/g,对应的PAHs沉积通量为150~210t/a。估算结果与实测沉积物中PAHs含量和沉积通量结果基本吻合,表明实验室模拟实验获取的化合物Koc值适用于东海颗粒相-水相间的分配模型,证实悬浮颗粒物有机碳含量在控制PAHs两相分布过程中起着重要作用。同时,该方法为海洋沉积物中PAHs沉积通量的估算提供一种新途径。     

海岛礁光学和雷达影像基于改进非子采样小波变换的自动配准

Homologous feature point extraction is a key problem in the optical and synthetic aperture radar （SAR） image registration for islands. A new feature point extraction method using a threshold shrink operator and non-subsampled wavelet transform （TSO-NSWT） for optical and SAR image registration was proposed. Moreover, the matching for this proposed feature was different from the traditional feature matching strategies and was performed using a similarity measure computed from neighborhood circles in low-frequency bands. Then, a number of reliably matched couples with even distributions were obtained, which assured the accuracy of the registration. Application of the proposed algorithm to SPOT-5 （multi-spectral） and YG-1 （SAR） images showed that a large number of accurately matched couples could be identified. Additionally, both of the root mean square error （RMSE） patterns of the registration parameters computed based on the TSO-NSWT algorithm and traditional NSWT algorithm were analyzed and compared, which further demonstrated the effectiveness of the proposed algorithm. The algorithm can supply the crucial step for island image registration and island recognition.     

Synoptic surveys of lakes Rotorua and Rotoiti

Surface and bottom water samples were collected from 39 widely spaced stations in Lake Rotorua in February 1967 and from 12 stations in Lake Rotoiti in March 1967. In Lake Rotorua, data obtained from these samples showed that small horizontal differences existed between the southern and northern parts of the lake probably related to the higher inflow of plant nutrients at the southern end and to the prevailing southerly wind concentrating phytoplankton populations at the northern end. Lake Rotoiti, which differed from Lake Rotorua in being thermally stratified, showed no important horizontal differences, Vigorous mixing in the strata probably being accomplished by deep seiches except in the shallow western basin of the lake, where the inflow from Lake Rotorua occurs. Serial vertical hauls for a zooplankton survey of Lake Rotoiti were taken from three stations in March 1967. The distribution of zooplankton was complex because diurnal vertical migrations of the animals were combined with horizontal movement of the water layers.     

台风“利奇马”对东中国海表层悬浮物浓度变化的影响

台风过程可使海洋悬浮物浓度的分布在短时间内发生极大变化,并影响海洋生态环境以及海洋资源的分布。受台风期间海洋观测数据的限制,台风过程对海洋悬浮物浓度的影响尚不明确。本文利用GOCI （Geostationary Ocean Color Imager,GOCI）卫星遥感数据,以2019年8月台风“利奇马”为例,对其过境前后东中国海表层悬浮物浓度的时空变化进行了定量研究。结果表明,台风“利奇马”对闽浙沿岸的影响程度最大,使悬浮物质量浓度中高值（≥5 mg/L）覆盖面积和浓度平均值分别增大92%和62%,影响持续时间为4 d;对长江口附近海域的影响程度次之,使悬浮物浓度中高值覆盖面积和浓度平均值分别增大19%和17%,影响持续时间为3 d;对苏北浅滩的影响程度最小,悬浮物质量浓度中高值覆盖面积变化不大,但浓度平均值增大了30%,影响持续时间为4 d。研究结果表明卫星遥感数据可以量化台风过程对东中国海表层悬浮物浓度的影响,弥补极端天气条件下无法进行现场观测的不足。     

Characteristics and origins of middle Miocene mounds and channels in the northern South China Sea

Numerous elongated mounds and channels were found at the top of the middle Miocene strata using 2D/3D seismic data in the Liwan Sag of Zhujiang River Mouth Basin(ZRMB) and the Beijiao Sag of Qiongdongnan Basin(QDNB). They occur at intervals and are rarely revealed by drilling wells in the deepwater areas. Origins of the mounds and channels are controversial and poorly understood. Based on an integrated analysis of the seismic attribute, palaeotectonics and palaeogeography, and drilling well enco...     

Delving into three-dimensional structure of the West Luzon Eddy in a regional ocean model

The three-dimensional structure and associated dynamics of the prominent cold (cyclonic) West Luzon Eddy (WLE) were investigated by a high-resolution regional ocean model. The WLE was horizontally and vertically heterogeneous, exhibiting asymmetric structures in the circulation, vorticity, vertical motion and energy distributions within the eddy. The asymmetry was mainly attributed to the existence of an eddy dipole formed by a coexisting warm (anti-cyclonic) eddy to the south of the WLE. Analysis of the momentum balance revealed that the coexistence of two eddies intensified barotropic pressure gradients in the southern WLE to locally enhance the eastward jet. The positive (negative) vorticity of the jet strengthened (weakened) the eddy in the southern sector (periphery), which, together with the formation of a subsurface density front, intensified (suppressed) the corresponding upward motion and cooling. The baroclinic pressure gradients opposed the dominant barotropic components and spun down the eddy at greater depths with stronger weakening in the southern sector near the front. Asymmetric energy distributions showed that larger mean kinetic energy (MKE) and eddy available potential energy (EAPE) were stored in the southern sector of the WLE. While the larger MKE was directly linked with the stronger barotropic currents, the larger EAPE in the southern WLE was formed by baroclinic energy conversions due to a strong density gradient at the front.     

Taiwan and China: A unique fisheries relationship

Taiwan and China have a long history of sharing marine resources in the China Seas. However, due to political issues, the two sides have yet to formalize collaboration and interaction despite such a close geographical relationship. The lack of formal collaboration means they cannot manage fisheries or conserve resources as a team. The lack of collaboration in the regional fisheries management organizations also means a mutually beneficial situation for the two sides is yet to be achieved. Recognizing this, the two sides began negotiations in 2008 and have since signed agreements on fisheries co-operation projects. This paper discusses the unique fisheries relationship between Taiwan and China, and the characteristics of their fishing industries. The paper also presents the latest update on the collaboration between the two sides. Finally, this paper proposes practical solutions for resolving outstanding issues between the two sides’ fishing industries.     

东海太平洋褶柔鱼角质颚的形态学分析

依据2010年9月及2011年5月、9月东海渔业资源底拖网调查采集的139尾(雌性66尾,雄性73尾)太平洋褶柔鱼(Todarodes pacificus)样本的胴长、体重和角质颚各部分的长度数据,分析了东海太平洋褶柔鱼角质颚的形态学特征。结果表明:(1)太平洋褶柔鱼角质颚上、下颚的喙长(RL)、头盖长(HL)、脊突长(CL)、翼长(WL)、翼宽(WW)等长度差异较大;(2)伴随RL的增长,HL、CL、WL、WW呈现极显著的异速生长特征(P<0.001);(3)各长度指标随胴长、体重的增长呈显著的线性增长趋势;(4)RL/CL、HL/CL的比值非常稳定,随胴长、体重的变化很小,可作为东海太平洋褶柔鱼角质颚形态特征的稳定指标。