鄂尔多斯盆地中生代晚期以来大地热流的变化及其对生态环境格局和演变的影响

鄂尔多斯盆地的西北部、东北部和南部三个区域现今大地热流平均值分别为56．3、67．3和65．3mW／m^2，对应的生态环境格局也有明显的差异。研究表明，大地热流每增加4～5mW／m^2可使年均地表温度升高约l℃，使最低月均地表温度升高2。C以上。鄂尔多斯盆地东北部的平均大地热流比西北部高出11mW／m^2，东北部年均地表温度可能比西北部高出2～3℃，其最低月均地表温度可能比西北部高出4～6℃。西北部的大地热流平均值已经低于维持地表生态系统延续所需大地热流的临界值(57mW／m^2)，其自然生态系统整体上已经处于脆弱境地；东北部和南部的大地热流均大于57mW／m^2，自然生态系统均尚较稳健。东北部的沙漠化可能是风沙侵入的结果，其生态应该是可以恢复的。整个西北部作为一个整体看，72万年以前大地热流就已衰减到临界值以下，区域生态系统渐趋脆弱，开始整体上向荒漠化演变。     

碳酸岩Sr、Nd、Pb 同位素地球化学研究评述

碳酸岩是出露相对较少的幔源岩石，其中Sr与Nd是研究地幔物质组成的主要对象之一。本文统计了世界上主要碳酸岩的锶、钕、铅同位素组成特征；研究显示，碳酸岩源区主要是洋岛玄武岩高U／Pb的HIMU端员和富集端员(EM1或EM2)的混合作用；此外大部分碳酸岩的锶、钕同位素落在大洋玄武岩范围内；这些均表明其成因与地慢柱有密切联系。碳酸岩及与之共生的硅酸岩的同源或独立源区模式部很难充分解释两者同位素组成特征，逭反映碳酸岩的演化模式涉及更复杂的过程。可能是俯冲作用使碳酸岩源区经历不同时间和程度的富集、亏损过程导致地幔源区成分不均一。     

GPS广播星历参数拟合算法

介绍了GPS广播星历参数的最小二乘估计方法。推导了相应的计算公式。计算结果表明。文中给出的公式是正确的，其拟合精度以用户距离误差(URE)示时，对预报轨道的损失小于1cm。     

民乐、山丹6.1级地震异常及台站实现短临预报的思考

在综合分析了民乐-山丹6.1级地震前张掖中心台范围内震兆异常特征的基础上,总结了本次地震前该台的短临预报过程及存在的问题,对今后台站如何搞好地震短临预报工作进行了探讨.     

On the applicability of KirchofPs law and the principle of heat balance in thermal infrared remote sensing:A non-isothermal system

This paper proposes a basic equation of thermal radiation interaction between surface objects on the basis of the principle of heat balance in the interface. The solution of this equation takes account of the contribution of sensible heat flux and latent heat flux more completely, compared with traditional solution for surface cooling and heating processes. By the aid of the experimental data conducted in the Xiaotangshan experimental site, Beijing, both the non-applicability of Kirchoff's law and the measurability of surface emissivity in a non-isothermal system have been highlighted. Two methods called ventilation and time-delay compensations have been proposed to reduce the error induced by change of surface temperatures of non-isothermal objects during the measurement of emissivity. Based on the solution of the basic equation, this paper has analyzed and pointed out the misunderstanding in comprehension and application of Kirchoff's law published in literature.     

海南博螯沿岸地貌与人类活动的潜在影响

The Boao coastal system along the eastern coast of Hainan Island is a dynamic delta-tidal inlet-barrier formed during the late Holocene. The delta developed inside a shallow lagoon barred by a sandy barrier with a narrow, shallow tidal inlet opening. Two major distributary channels separated by small islands characterize the delta. The lagoon is silting up receiving and trapping sediments from both the river and, in minor measure during storms, through the tidal inlet opening and barrier washovers. The barrier at the tidal inlet is highly dynamic and changes its form, accreting (migrating spit) against the inlet during fair-weather conditions and being eroded during storms and river floods.The delta has almost completely filled the lagoon and major concerns exist on the effect that ongoing large development plans may have on the environment. These concerns include the effect on floods and rate of siltation once banks of the islands have been stabilized and floodwater and sediment load are impeded from spreading over the lowlands, and the effect of increasing pollutant loads from the new facilities on the ecosystems of the increasingly restricting lagoon water and on the seashores.     

“青藏高原南部空白区基础地质调查与研究”计划项目新成果、新进展

通过2 0 0 4年度各相关图幅的大力工作,在基础地质、矿产和资源等方面取得了大量实际材料,综合研究区域构造地层格架、青藏高原地质图和青藏高原南部火山岩及其地球动力学意义等,取得重要进展和新认识,在矿产资源、旅游和人文景观等方面也取得重要阶段性成果。     

沉降-时间曲线呈“S”型的证明及其应用——从土体本构关系

从土体本构关系出发,严格证明了在线性加载或近似线性加载情况下(这和岩土工程实际加载相类似),沉降-时间曲线呈“S”型,并由此建立了新的沉降-时间预测模型,工程应用证明了该模型的合理性。     

江西赣县大埠钨多金属矿田成岩成矿时空结构与找矿预测

大埠矿田位于南岭成矿带东段,是于都-赣县钨多金属矿集区重要组成,区内已发现钨多金属矿床（点）五十余处,矿床类型包括石英脉型、矽卡岩型、云英岩型和细脉浸染型等,各类矿化主要围绕大埠复式花岗岩体产出。然而,大埠矿田岩浆作用具有明显的多期次、多阶段的特点,各期次成岩成矿时代尚缺乏系统研究,各类岩浆岩与矿化关系争议较大。文章在岩体地质和矿床地质调查基础上,通过LA-(MC)-ICP-MS锆石U-Pb定年、锆石微量元素和Hf同位素分析,精确厘定了大埠花岗岩的成岩时代,探讨了多期次岩浆活动对区内成矿作用的贡献。锆石U-Pb定年结果分别为(429.1±4.7)Ma、(430.0±5.8) Ma、(431.8±4.7) Ma和(158.3±4.1) Ma,结合岩体地质填图信息,笔者认为大埠复式花岗岩基由加里东期和燕山期两部分组成。两期花岗岩均属于高钾钙碱性、过铝质S型花岗岩系列,两者均出现Eu负异常,燕山早期Eu负异常更明显。两期岩体锆石的ε_Hf(t)值分别为-6.3~-1.3与-11.4~-7.1,对应二阶段模式年龄为1.49~1.82 Ga与1.66~1.93 Ga,指示其母岩浆为中元古代的地壳部分熔融形成。锆石微量元素特征显示,两期花岗岩均为陆壳源区、具有相近的结晶温度,燕山早期花岗岩相对于加里东期有更高的结晶分异程度,有更高的氟含量,与钨成矿具有更强的相关性。大埠矿田钨多金属成矿时代集中在159~155 Ma,紧随燕山早期花岗质岩浆侵位而形成。基于大埠矿田成岩成矿时代格架研究,结合花岗岩成矿专属性和成矿地质条件分析,构建了区内钨多金属矿勘查模型,指明了大埠矿田细脉浸染型、云英岩型、内带石英脉型钨矿的找矿方向,预测大埠岩体东北部的燕山早期隐伏岩体具有寻找“合龙式”石英大脉型和细脉-云英岩型钨矿的潜力。