基于遗传小波神经网络的海底声学底质识别分类

分割海底声纳探测图像,提取单元特征向量进行主成份分析,选取均值、标准差、对比度、相关系数、能量及同质性作为训练特征向量,构建小波神经网络。利用遗传算法优化小波神经网络的初始权值及小波参数,对砂、礁石、泥3种底质类型分别进行训练,并得到3种底质的测试精度都在90%以上,优于单独利用小波神经网络进行训练时的测试精度,克服了小波神经网络训练时易陷入局部极小的固有缺陷,表明基于遗传算法的小波神经网络可有效用于海底底质声纳图像的识别和分类。     

始新统油气系统:泰国湾东北部油气勘探新层系

泰国湾区域经历了前裂谷期、裂谷期、裂后期的构造演化阶段,形成了多个裂谷盆地。泰国湾区域东北部在渐新世经历了一次明显构造反转,较泰国湾区域大部分地区强烈。通过对比区内钻井,结合地震解释,对该区的沉积特征和构造演化进行了分析,认为这次反转构造导致了反转构造带上构造、沉积特征与邻区有较大的不同。由于这次反转构造,泰国湾东北部在新层系发育新类型的油气系统,即深部的始新统油气系统:烃源岩为中始新统湖相泥岩,储层为上始新统-渐新统三角洲相砂岩,盖层为下中新统三角洲前缘相泥岩和上中新统以上的海相泥岩。该油气成藏系统已被钻井钻遇油气显示,是本区有效油气成藏系统。     

Distributional characteristics of grain sizes of surface sediments in the Zhujiang River Estuary

Distributions of the parameters of sedimentary grain sizes and their correlations were studied to trace the sources of silts and their movement trends in the Zhujiang River Estuary based on the analyses of grain sizes from more than 1080 sedimentary samples. The distributions of the median diameter, public value, quartile deviation, and skewness of sediments were complex in the Zhuiiang River Estuary mainly because of the impact of the matter source regions, distances from the source regions, and hydrodynamic conditions, such as waves, tidal currents, and coastal currents. Analyses of the parameters of the grain sizes for the various types of sediments showed that the distributions of the surface sediments in the Zhujiang River Estuary were controlled by many factors. Their matter sources were mainly the sediments discharged from the runoffs and ebb tidal currents, and from the open sea. The sediments mainly moved by suspension movement. The silts formed a large area of sediments with suspended fine silts in the Zhujiang River Estuary by internal adjustment transportation in the area, and moved toward the western coast of the Zhujiang River Estuary under the effect of Coriolis forces and coastal currents.     

南大西洋沉积物中多环芳香化合物的组成特征研究

10 samples of sediments obtained from the South Mid-Atlantic Ridge were measured for the abundances and distributions of polycyclic aromatic compounds(PAHs). The total concentrations of PAHs(∑PAHs) ranged from 2.768 to 9.826 μg/g dry sediment. The ∑PAHs was higher in sample 22V-TVG10 and sample 26V-TVG05 which were close to hydrothermal fields, with the lowest value in sample 22V-TVG14 which was farthest from hydrothermal fields, suggesting a probable hydrothermal origin of ∑PAHs of samples. Approximately nine kinds of PAHs were identified, and low molecular mass tricyclic and tetracyclic aromatic compounds were predominant in the samples. The concentrations of fluoranthene which were typical as hydrothermal alteration compounds were the highest among PAHs with dry weight between 0.913–3.157 μg/g. The phenanthrene homologue was most abundant in the samples, and the ratios between parent phenanthrene and methylphenanthrene which probably reflected the degree of hydrothermal alteration ranged from 0.097 to 1.602. The sample 22V-TVG10 possessing a maximum ratio value showed the intense influence of the hydrothermal alteration on this sample, which might further imply that PAHs in sediments were mainly derived from the hydrothermal alteration.     

桑沟湾及附近海域表层沉积物碳氮同位素分析及有机质来源

Naturally existing stable carbon and nitrogen isotopes are important in the study of sedimentary organic matter sources. To identify the sources of sedimentary organic matter in Sanggou Bay and its adjacent areas, which is characterized by high-density shellfish and seaweed aquaculture, the grain size, organic carbon(OC), total nitrogen(TN), carbon and nitrogen isotopic composition(δ13C and δ15N) of organic matter in the surface sediment were determined. The results showed that, in August, sedimentary OC and TN ranged from 0.17% to 0.76% and 0.04% to 0.14%, respectively. In November, OC and TN ranged from 0.23% to 0.87% and 0.05% to 0.14%, respectively. There was a significant positive correlation between OC and TN(R=0.98, P0.0001), indicating that OC and TN were homologous. In August, the δ13C and δ15N of organic matter varied from-23.06‰ to-21.59‰ and 5.10‰ to 6.31‰, respectively. In November, δ13C and δ15N ranged from-22.87‰ to-21.34‰ and 5.13‰ to 7.31‰, respectively. This study found that the major sources of sedimentary organic matter were marine shellfish biodeposition, seaweed farming, and soil organic matter. Using a three-end-member mixed model, we estimated that the dominant source of sedimentary organic matter was shellfish biodeposition, with an average contribution rate of 65.53% in August and 43.00% in November. Thus, shellfish farming had a significant influence on the coastal carbon cycle.     

近50年来杭州湾七姊八妹列岛海域海床演变分析

七姊八妹列岛海域位于杭州湾南部的灰鳖洋内,除了岛礁周围局部存有深沟外,其余地区海床平缓.为了探究该海域海床演变情况,在了解杭州湾来水来沙特征基础上,分析了七姊八妹列岛海域的水动力、悬沙和底质分布特征.不同时期海图的对比分析表明,该海域近岸水深较小,人类活动频繁,围涂筑堤工程较多,一直处于淤积状态,属淤涨型岸滩,而离岸较远的海域,泥沙难于落淤而随潮反复搬运,基本处于冲淤平衡状态.1962～2008年这46 a间,七姊八妹列岛海域总体呈现与岸线走向一致的淤积、冲刷间隔分布的冲淤带.平均淤积厚度约2.2 m,淤积幅度约5.0 cm/a,大多数地方平均冲刷厚度约2.4 m,冲刷幅度约5.0 cm/a.这些特点与当地的水动力条件和泥沙沉积特性相一致.     

东太平洋海隆深海热液区沉积物古菌多样性分析

采用PCR-RFLP方法对东太平洋海隆深海热液区3个站位沉积物中的古菌多样性进行了初步研究.结果显示,从古菌16S rRNA基因文库中随机挑取的296个阳性克隆分属奇古菌门（Thaumarchaeota,47.64%）、广古菌门（Euryarchaeota,44.93%）、泉古菌门（Crenarchaeota,6.77%）和未分类古菌（0.68%）,其中优势菌群为奇古菌门的亚硝化侏儒菌属（Nitrosopumilus,35.47%）和广古菌门的热原体纲（Thermoplasmata,27.03%）,DHVE3、DHVE5、DHVE6、MBGB和MBGE类群在沉积物样品中也均有发现.另外,3个站位沉积物中古菌类群组成存在差异,S5-TVG1站位样品文库的97个古菌克隆分属奇古菌门（49.48%）、广古菌门（49.48%）和泉古菌门（1.03%）,S14-TVG10站位样品文库的103个古菌克隆由奇古菌门（84.47%）和广古菌门（15.53%）组成,S16-TVG12站位样品文库的96个古菌克隆包括广古菌门（71.88%）、泉古菌门（19.79%）、奇古菌门（6.25%）和未分类古菌（2.08%）.研究结果表明,东太平洋海隆深海热液区沉积物中古菌多样性丰富,存在着许多新的古菌菌群;不同站位古菌菌群结构以及多样性存在差异,这与其所处环境的热液活动密切相关.     

洋山深水港区海域秋、冬季沉积物中重金属来源分析及生态风险评价(英文)

通过测定洋山深水港区海域2010~2013年6个航次秋、冬季沉积物中重金属含量,分析其时空差异,结果表明该海域沉积物重金属总体含量较低,空间分布较为均匀,Hg、Zn、Pb、Cd含量秋季明显高于冬季,As、Cu含量的季节性波动较小,用因子分析法研究该海域重金属来源,发现陆源工业、船舶航运排污以及有机质降解是研究海域Pb、Cd、Zn的主要来源;农业污染、码头货物装卸残留及建筑垃圾支配着Cu、As、Hg的来源。SQG-Q生态风险评价表明研究海域沉积物中重金属均存在中、低度的生态风险,秋季的生态风险高于冬季,Hg和Cu是主要生态风险因子;地累积指数法评价结果显示研究海域基本不受Hg、As、Zn、Pb的污染;Cd、Cu以轻度污染为主,部分站位属于偏中度污染,6种重金属污染程度依次为:CdCuPbZnHgAs。因子综合得分评价表明,重金属污染相对严重的站位依次为5号、4号及3号站位。但总体看来洋山深水港区附近海域沉积物中重金属污染状况属于轻度污染。     

定向岩芯构造分析及在金矿勘查中的运用

系统测量定向岩芯中构造面的α角和β角,结合钻孔的方位角和钻孔倾角,通过赤平投影可以还原真实的构造面产状.通过穿过金矿体的定向岩芯的构造编录和系统分析,计算矿体中的主要含矿节理、含矿蚀变带等构造面的产状,并进行统计分析,可以了解矿化与各类构造之间的关系,计算矿体的空间产状,并推断主矿体的延伸等,为矿区的深部勘查设计提供依据.     

Thermal and compositional stratification of the inner core

The improvements of the knowledge of the seismic structure of the inner core and the complexities thereby revealed ask for a dynamical origin. Sub-solidus convection was one of the early suggestions to explain the seismic anisotropy, but it requires an unstable density gradient either from thermal or compositional origin, or from both. Temperature and composition profiles in the inner core are computed using a unidimensional model of core evolution including diffusion in the inner core and fractional crystallisation at the inner core boundary (ICB). The thermal conductivity of the core has been recently revised upwardly and, moreover, found to increase with depth. Values of the heat flow across the core mantle boundary (CMB) sufficient to maintain convection in the whole outer core are not sufficient to make the temperature in the inner core super-isentropic and therefore prone to thermal instability. An unreasonably high CMB heat flow is necessary to this end. The compositional stratification results from a competition of the increase of the concentration of light elements in the outer core with inner core growth, which makes the inner core concentration also increase, and of the decrease of the liquidus, which makes the partition coefficient decrease as well as the concentration of light elements in the solid. While the latter (destabilizing) effect dominates at small inner core sizes, the former takes over for a large inner core. The turnover point is encountered for an inner core about half its current size in the case of S, but much larger for the case of O. The combined thermal and compositional buoyancy is stabilizing and solid-state convection in the inner core appears unlikely, unless an early double-diffusive instability can set in.