On salinity regimes and the vertical structure of residual flows in narrow tidal estuaries

An examination is made of the circulation in narrow estuaries subject to a predominant tidal forcing. Velocity structures are derived separately for residual flow components associated with (a) river flow, (b) wind stress, (c) a well-mixed longitudinal density gradient and (d) a fully stratified saline wedge. Dimensionless parameters are introduced to indicate the magnitude of each component and these parameters are evaluated for 9 major estuaries, thereby revealing their sensitivity to each component.For a channel of constant breadth and depth, formulae are deduced for the length of saline intrusion, L. Comparisons with observed data show that such formulae may be used with confidence to predict changes in L arising from variations in river flow, tidal range or channel depths.The level of stratification is shown to be related to a product of two parameters, one associated with velocity structure and a second involving the square of the ‘flow ratio’ $\text{u}\text{u}\text{?}$ (i.e. residual velocity/amplitude of the tidal velocity). This relationship provides a simple classification system for estuarine stratification which can be used to indicate the sensitivity of any particular estuary to changing conditions.     

利用卫星遥感资料对南海北部陆架海洋表层温度锋的分析

利用7年(1993～1999)月平均的SST卫星遥感资料，分析了南海北部陆架区域海洋表层温度锋在一年中的逐月变化特征，表明南海北部陆架海洋表层温度锋存在明显的季节内变化。结合风场的卫星遥感资料，分析了东北季风对南海北部陆架温度锋的影响，表明东北季风风速的增加有利于温度锋强度的增强。通过对黑潮南海流套入侵较强的1999年2月与流套入侵较弱的1998年2月的SST卫星遥感资料的对比分析，考察了黑潮南海流套的入侵对南海北部陆架温度锋的影响，结果表明黑潮流套的较强入侵能够增加陆架温度锋的强度，对温度锋的走向也会产生一定的影响。     

南海中部海区次表层NO2^——N的最大值

本文根据1983年9月至1985年1月南海中部海区综合调查所获得的NO_2~--N及有关参数的观测资料,分析了该海区NO_2~--N的分布变化特征及其与环境因子的关系。结果表明,调查海区NO_2~--N含量的变化范围在0～0.54μmol/L之间,其中小于0.05μmol/L的测定值约占测定总数的82.1%,而大于0.05μmol/L测定值基本上出现在50～150m层。文中还对该海区次表层NO_2~--N最大值形成的机理作了初步探讨,指出密度跃层的终年存在、铵的氧化和浮游植物的代谢过程是调查海区次表层NO_2~--N最大值形成的主要因素。     

塞曼石墨炉原子吸收法直接测定海水中的铬

海水基体对Cr有增感作用。本文研究了抗坏血酸、柠檬酸三铵、酒石酸、乙酸铵等有机基体改进剂对消除基体干扰效果。前二者均有效地消除基体干扰,但1％抗坏血酸 1％柠檬酸三铵混合试剂的效果更好,它不仅可以消除基体干扰,还可降低背景及噪声,Cr的吸收峰也较平滑。本法准确,相对偏差在0.7—4.4％范围内。回收率在92—109％范围内。若海水Cr含量低于定量下限时,可采用多次进样法。     

胜利二号极浅海步行坐底式钻井平台防腐措施研究

本文根据胜利二号极浅海步行坐底钻井平台的作业和工作环境特点，进行了防腐措施研究，设计了切合实际的防腐措施。该平台在海上作业近四年进坞修理，经观测防腐情况良好。     

海水入侵水化学指标及侵染程度评价研究

选择Ｃｌ＾,Ｍ、Ｂｒ＾－,ｒＨＣＯ３／ｒＣｌ及ＳＡＲ５项水化学要素作为综合判断海水入侵的指标：染程度划分为４级;确定了各项指标入程度的等级范围。入侵程度的衡理采用模糊数学综合判模型。     

伽师强震群的深部动力学条件

根据天山造山带及其两侧的塔里木盆地和准噶尔盆地的岩石圈二维速度结构、二维密度结构、二维电性结构、壳幔过渡带的详细结构以及大地热流和震源深度的分布,再结合对新疆西北部的蛇绿岩带、高压变质带和岩浆岩分布的综合分析,建立了天山造山带的地球动力学“层间插入消减”模型。该模型认为,塔里木板块的中上地壳在库尔勒断裂附近向天山造山带的中下地壳层间插入;而下地壳连同岩石圈地幔向天山造山带的上地幔俯冲消减。在天山的西段（哈萨克斯坦境内）,费尔干纳地块由北向南插入到南天山之下约180km的深处,在其东段（中国境内）,塔里木盆地由南向北插入南天山之下。这两个具有不同方向的下降板片的接触部位为费尔干纳走滑断裂。我国的伽师、喀什、乌恰地震区均落在这两个具有不同俯冲方向板块的结合部位附近,有着特殊的深部构造背景。南、北两大板块的双向挤压必定产生强大的应力,在地震区附近,这种应力的积累与释放具有4个显著的特点：（1）板片的俯冲消减速度约高达每年22mm左右;（2）应力的积累与释放速率加快;（3）应力释放较容易;（4）应力释放较为集中。这4个特点可能是伽师地区在较短的时间内连续发生数次强震的构造因素。     

Zoning and layering in diorites of the scottish caledonian appinite suite

Dioritic plugs (< 1 km across) are common associates of the late Caledonian, post-tectonic granites of the Scottish Highlands. These contain a very wide range of rock types from ultramafic through mesocratic diorites to anorthositic and granitic. These rocks form steeply dipping, wall-parallel layers and zones within the plugs. Outer layers are shown to form first, inner layers later. Mafic zones are composed of the minerals seen as phenocrysts in chilled margins and have the chemical characteristics of cumulates. The inner margins of the mafic zones reflect the onset of plagioclase crystallization. Core zones also show inward variations in mineralogy and texture which define vertical, wall-parallel cylinders. These variations are ascribed to fractional crystallization accompanying accretion of rock onto the pipe walls. Cores in different intrusions may be mafic, mesocratic, or leucocratic, which indicates vertical zonation in the bodies. The mafic cores additionally show that recharge with less evolved magma occurred in some cases. The few larger (> 1 km diameter) intrusions show examples of layering and lamination dipping at low to moderate angles. These indicate the beginning of a change from wall-dominated to floor-dominated crystallization as intrusion diameter increases. A comparison is made with the nature and origin of layering in other intrusions.     

The thermal maturity of sedimentary basins as revealed by magnetic mineralogy

The thermal evolution of sedimentary basins is usually constrained by maturity data, which is interpreted from Rock-Eval pyrolysis and vitrinite reflectance analytical results on field or boreholes samples. However, some thermal evolution models may be inaccurate due to the use of elevated maturities measured in samples collected within an undetected metamorphic contact aureole surrounding a magmatic intrusion. In this context, we investigate the maturity and magnetic mineralogy of 16 claystone samples from Disko-Svartenhuk Basin, part of the SE Baffin Bay volcanic margin. Samples were collected within thermal contact metamorphic aureoles near magma intrusions, as well as equivalent reference samples not affected by intrusions. Rock-Eval pyrolysis (T_max), and vitrinite reflectance (Ro) analysis were performed to assess the thermal maturity, which lies in the oil window when 435°C ≤ T_max ≤ 470°C and 0.6%–0.7% ≤ Ro ≤ 1.3%. In addition, we performed low- (<300K) and high-temperature (>300K) investigations of isothermal remanent magnetization to assess the magnetic mineralogy of the selected samples. The maturity results (0.37% ≤ Ro ≤ 2%, 22°C ≤ T_max ≤ 604°C) show a predominance of immature to early mature Type III organic matter, but do not reliably identify the contact aureole when compared to the reference samples. The magnetic assemblage of the immature samples consists of iron sulphide (greigite), goethite and oxidized or non-stoichiometric magnetite. The magnetic assemblage of the early mature to mature samples consists of stoichiometric magnetite and fine-grained pyrrhotite (<1 μm). These results document the disappearance of the iron sulphide (greigite) and increase in content of magnetite during normal burial. On the other hand, magnetite is interpreted to be the dominant magnetic mineral inside the contact aureole surrounding dyke/sill intrusions where palaeotemperatures indicate mature to over-mature state. Interestingly, the iron sulphide (greigite) is still detected in the contact aureole where palaeotemperatures exceeded 130°C. Therefore, the magnetic mineralogy is a sensitive method that can characterize normal burial history, as well as identify hidden metamorphic contact aureoles where the iron sulphide greigite is present at temperatures beyond its stability field.     

Wind impact on pollutant transport in a shallow estuary

A three-dimensional numerical model, EFDC （ environmental fluid dynamics code） is applied to the Pamlico River Estuary （PRE） in eastern North Carolina of the United States to examine the wind impact on pollutant age distributions and residence time. A series of model experiments representing base case, remote-wind-induced water level set-up and local winds cases are conducted. Model results indicate that the pollutant mean age and the system residence time are functions of gravitational circulation in the PRE. The system responses to remote-wind-induced water level set-up are different in different portions of the PRE. Under such condition, dissolved substances in the upstream portion of the PRE have a younger age and shorter residence time （compared with the base case） , by contrast, they have a older age and longer residence time in the downstream portion of the PRE. Upriver and downriver local winds appear to have opposite impacts on pollutant age distributions. The substances are retained much longer within the PRE under upriver wind than those under downriver wind. The model results also suggest that across - river winds may lead to longer residence time through enhanced turbulence mixing, which slows down the gravitational circulation in the PRE.