湘西沃溪钨锑金矿床地质地球化学特征

沃溪钨锑金矿床产于元古界板溪群马底驿组中、上段紫红色绢云母板岩中,受层间断裂带控制。矿体具斜列延伸、多层产出、近似等间距分布特点,见有层间石英脉、网状石英脉和节理裂隙脉三类矿体。金矿物以次显微、显微金为生,主要赋存于以黄铁矿、辉锑矿为主的硫化物中,As、Sb是其标型元素。成矿物质与赋矿地层密切相关,成矿流体是非岩浆源的,成矿作用是在中低温度、偏低盐度、中性略偏酸性的变质热液中发生的,构造运动对成矿过程起着控制作用。矿床属于火山沉积—变质热液成因。     

吉林省地下水中的元素地域性分布与地方病

本文以吉林省地下水中的元素地域性分布规律入手,对吉林省流行的饮水型地方性疾病进行探讨。着重论述吉林省三大地域地下水元素及化学组份背景特征与地方病分布的相关性。同时,结合微地貌等水文地质条件,进一步阐述地下水元素及化学组分特征与地方病发病关系。     

考虑震源机制解的地震丛集区搜索方法

构造带区段的划分对地震区划与构造演化等研究有着重要作用,而地震丛集区可以为构造带区段的划分提供参考依据.本文发展了一种考虑震源机制解的地震丛集区搜索方法：基于震源机制解的四元数表示方法来定量评估不同地震的震源机制解的相似程度,并以满足给定相似度阈值条件的地震所占比例作为判据来确定地震丛集区.合成数据的测试结果显示,该方法能够对地震丛集区做有效搜索并区分具有不同震源机制特征的丛集区.将该方法应用于2011年日本M9.0东北大地震显示,搜索得到的地震丛集区与实际观测到的余震特征分布具有较好的一致性,表明该方法可以为实际的地震丛集区划分提供一条有效的途径.     

A mineral survey of the Cretaceous of the Benue Valley,Nigeria

The economic importance of the Cretaceous sequence of the Benue Valley is highlighted. The linear sedimentary basin or trough, as sometimes described, is underlain essentially by marine Cretaceous rocks, starting from the Middle Albian, and ranging to the Maastrichtian. There is, so far, no evidence of the occurrence of younger rocks in the Upper and Middle Benue area, though in the Lower Benue and the Niger Delta regions, Palaeocene to Recent formations overlie the older formations.The depositional processes and the tectonics associated with this period caused the emplacement of an accumulation of a number of important minerals of sedimentary and igneous origins, including lead-zinc, barytes, limestone and coal. There are indications of the possible occurrence of evaporites as evidenced by brine-springs associated with collapse features and fracture systems related to diapiric dome structures. The use of the minerals in the Nigerian economy is discussed. There are also favourable prospects for uranium and hydrocarbons. The immediate future will usher in a period of intensive exploration work aimed at evaluating these resources.     

数字图像区域周长计算的原理和方法

从数学中的随机集和整体几何理论出发,讨论了数字图像区域周长计算的原理和方法。从理论分析及实验结果得出了该方法具有精度高、适应性强、易于计算机实现等特点。     

中国山地垂直自然带研究的进展

中国是一个多山的国家,山地占全国陆地面积的３３％,喜马拉雅运动基本奠定了山地格局,东西季风环流定格了自然地带的水平 山地垂直自然带确立了基础。从山地垂直自然带基带的性质出发,一般可以分为１８种主要类,分别属于季风性带谱系统和大陆性带谱系统。     

城市工程地质问题的经济分析

随着城市建设步伐的加快, 人类已面临着许多城市工程地质问题, 此类问题一旦形成则造成经济损失, 预防其发生则需要代价。本文从城市工程地质问题的经济分析着手, 对城市建设的成本进行了研究, 对城市规划、城市建设和城市管理具有现实意义。     

REGCM2和SUCROS模式的双向耦合模拟试验

文中利用NCAR区域气候模式REGCM2和荷兰WAGENINGEN农业大学的作物生长过程模式SUCROS在中国东部平原进行了作物 大气双向耦合的模拟试验。初步的研究结果表明 ,该双向耦合模拟试验 (R/S)能较好地描述大气和农作物间动态的基于生物过程的相互作用。R/S模拟试验不仅能真实合理地反映植物叶面积指数的逐日变化特征 ,更好地描述中国东部平原的陆面物理过程 ,而且改善了REGCM2对中国东部地区夏季降水和地面温度的数值模拟。该项研究对进一步认识和研究气候系统与陆地生态系统的相互作用具有一定的意义。     

MM5模式对区域气候模拟的性能试验

利用1998年6月NCEP资料和6月2日00：00地表资料及美国NCAR／PENN州的MM5对1998年6月我国南方降雨过程进行了气候模拟的性能试验，模拟结果表明，MM5基本上可模拟出局地大气环流和区域尺度上的强对流过程造成的雨区，降雨强度和强降水中心位置，但模拟的雨量与实际值相差较大，模拟值再现了我国夏季降水异常的空间分布特点，模式可向区域气候模式发展，但该模式模拟的1998年6月副高强度比其实际值的强度更强，故导致更多的水汽进入降雨区，造成过多的降雨。     

Dispersion Modelling of the Kilauea Plume

Emissions from the Kilauea volcano pose significant environmental and health risksto the Hawaiian community. This paper describes progress toward simulating theconcentration and dispersion of plumes of volcanic aerosol after they emanate from thePu'u O'o vent of the Kilauea volcano.In order to produce an accurate regional forecast of the concentration and dispersionof volcanic aerosol, the Hybrid Single-Particle Lagrangian Integrated Trajectory(HY-SPLIT) model was used. Wind fields and thermodynamic data from the non-hydrostatic Mesoscale Spectral Model (MSM) were employed as input for theHY-SPLIT model. A combination of satellite remote sensing, aircraft, and ground-based observations collected during a field experiment was used to validate the model simulation of aerosol distribution.The HY-SPLIT model shows skill in reproducing the plume shape, orientation, and concentration gradients as deduced from satellite images of aerosol optical depth.Comparison of the modelled and observed values suggests that the model was able to produce reasonable plume concentrations and spatial gradients downwind of the source. Model concentrations were generally less than those observed on the leeward side of the Island of Hawaii. This deficiency may be explained by a lack of (i) background concentrations, (ii) local sources of pollution and/or (iii) sea-breeze circulation in the prognostic input wind field. These results represent early progress toward the goal of future operational application of the HY-SPLIT model to predict volcanic aerosol concentrations in Hawaii. This may help mitigate their negative impacts of plumes respiratory health, agriculture, and general aviation.