带电α卡找矿法及其特点     

华荣洲  葛静霞 《铀矿地质》1985,(2)

带电α卡找矿法是铀矿普查中继α卡找矿法后发展起来的一种测氡找矿法。文章介绍了带电α卡找矿法原理及其在铀矿床上的试验结果,带电α卡找矿法比自然α卡找矿法具有更高的测氡灵敏度,并且卡上α强度与杯中氡浓度有良好的线性关系。自从J·W·卡特等人提出用α卡法找铀矿后,近年来国内外均在进行这一方面的试验或用于找铀矿。我们根据氡的短寿子体在初始态呈正离子,可以被电场加速漂移的特点,试验了“带电α卡”找铀矿的方法。“带电α卡”即是将α卡带电,形成一电场。由于电场的作用,使α卡比正常条件下能吸附更多的氡短寿子体,使α卡上的α强度相对增高,从而提高了α卡的测氡灵敏度。我们将一般条件下金属薄膜对氡短寿子体的吸附称为“自然吸附”(此时的α卡称为“自然α卡”或“α卡”以区别于带电α卡)。将电场作用下金属薄膜对氡短寿子体的吸附称为“电场吸附”。显然有电场吸附作用叠加时将比纯自然吸附作用强。自1981年以来,我们对带电α卡找矿法的原理,装置,野外找矿方法及其效果等力面进行了试验研究。用带电α卡法找铀矿时,α卡用镀铝聚脂薄膜制成,将α卡挂在塑料杯(容器)中,加上负300伏电压。然后将整个装置倒置在测点探坑中(见图1)。六小时后取出α卡,用辐射仪测量卡上α强度,则卡上α强度将与测点的氡浓度有关。  相似文献   

The Chemical Composition of Global Subducting Sediments and Its Geological Significance     

Renjie Zhao  Quanshu Yan  Haitao Zhang  Yili Guan  Zhenmin Ge  Long Yuan  Shishuai Yan 《地球科学进展》1986,35(8):789-803

Subducted sediments play an important role in crust-mantle interaction and deep mantle processes, especially for subduction zone magmatism and mantle geochemistry. The current rate of Global Subducting Sediments (GLOSS) is 0.5~0.7 km³/a. The GLOSS are composed of terrigenous material(76 wt.%), calcium carbonate(7 wt.%), opal(10 wt.%) and mineral-bound H₂O⁺(7 wt.%). The chemical compositions of GLOSS are similar to those of upper continental crust which is mainly controlled by the terrigenous materials, and yet the materials formed by marine processes will dilute the terrigenous materials. The components of subducted sediments are different among trenches. In the accretionary margin, the components of subducted sediments are similar to those of the upper crust, while in the non-accretionary margin the components are terrigenous materials plus those produced by marine processes. During subduction, subducted sediments will released fluids, melt or supercritical fluid to affect island arc/back-arc basin magmatism by means of aqueous fluid or sediment melt. In addition, a part of subducted sediments, together with underlying altered oceanic crust/lithosphere, recycle into the mantle and contribute to the mantle heterogeneity. Geochemical tracers indicate that subducted sediments play variable contributions to the magmatic processes in different tectonic setting. Thus, subducted sediments play an important role in two relatively independent dynamics systems (plate tectonics and mantle plume), as well as related mantle evolution models. As a result, by accurately calculating the compositions of subduction sediments and using various geochemical indicators, we can further limit the input and output fluxes of various elements or isotopes, and then obtain more accurately residual subducted components, which can provide us some important clues for geodynamic process.  相似文献   

吉林省太古宙TTG岩类固结的温度压力条件     

孙德有  周永胜 《吉林地质》1995,14(2):57-63

吉林省太古宙ＴＴＧ岩类型成于变质上壳岩系麻粒岩相变质作用晚期阶段。详细的岩相学研究表明，ＴＴＧ岩类中存在岩浆结晶的绿帘石，角闪石和黑云母等。绿帘石的出现标志了一定的压条件。  相似文献   

吉林南部太古宙英云闪长质片麻岩类的特征及成因     

孙德有  葛文春  吴福元  周永胜 《吉林大学学报(地球科学版)》1995,(4)

吉林南部太古宙英云闪长质片麻岩类主要由石英闪长质、英云闪长质、花岗闪长质和奥长花岗质片麻岩组成。地质学、岩相学、地球化学研究表明，它们是同源岩浆通过结晶分异作用形成的，最主要的分离矿物相是角闪石和斜长石。岩浆来源于下地壳角闪质岩石的部分熔融作用。  相似文献   

Magnetostratieraphy of the Red Beds in the Hengyang Basin     

Hsu Vindell  A.Baksi 《《地质学报》英文版》1995,69(2)

This paper discusses the Cretaceous-Tertiary magnetic polarity sequence of the the Hengyang Basin on the basis of magnetostratigraphic study. The age of each stratigraphic unit has been determined with the magnetic polarity time scale combined with 39Ar/40Ar dating, thus providing evidence for determining the geological ages of different formations. The authors assign the age of the Dongjing Formation of the Hengyang Basin to Early Cretaceous, the Shenhuangshan Formation to Early-Late Cretaceous, the Daijiaping Formation to Late Cretaceous, and the Dongtang and Xialiushi formations to Palaeocene.  相似文献   

A Sedimentological Study of Carboniferous Bauxitic Formations in North China   总被引：1，自引：0，他引：1  

Meng Xianghua  Ge Ming  Xiao Zengqi 《《地质学报》英文版》1987,61(2):95-117

The authors have found in their studies many new genetic types of microtextures of bauxite. A sedimentological genetic classification of bauxites based on these features and a division of the microfacies types of bauxites formed in major microenvironments are proposed. Four kinds of sedimentary sequence of bauxitic sediments have also been recognized. On these bases, a generalized sedimentary model of Carboniferous bauxites in North China is presented, in which storm-turbidite currents play an important role in the formation and enrichment of bauxite deposits.  相似文献   

Numerical simulation of groundwater flowing to horizontal seepage wells under a river   总被引：6，自引：0，他引：6  

Wei Wang  Ge Zhang 《Hydrogeology Journal》2007,15(6):1211-1220

A horizontal seepage well, consisting of an interconnected vertical well, galleries, chambers and small-diameter radiating bores, is used to acquire relatively clean water that has been filtered through natural alluvial deposits in a riverbed. It has wide application, especially in arid and semi-arid areas. The lack of calculation formulae or models for horizontal seepage wells, up until now, has resulted in several false applications. Based on the analysis of groundwater flow characteristics, it has been concluded that several flow regimes coexist and hydraulic head loss exists in the horizontal seepage well. To avoid the difficulty of confirming the flux or head distribution in such a complex system, the model boundary of the whole horizontal seepage well has been moved to that of just the vertical well, and the well-aquifer system was treated as a heterogeneous medium, where the horizontal seepage well itself is a highly permeability medium. A mathematical model has been developed, based on the coupled seepage-pipe flow, by the introduction of equivalent hydraulic conductivity according to different flow regimes. Then a three-dimensional finite difference numerical model, based on the mathematical model, was developed and applied to a horizontal seepage well in China. The numerical model verified the groundwater flow characteristics of the horizontal seepage well. An erratum to this article can be found at  相似文献   

太平洋副热带高压、西风环流、极涡指数变化与中国夏季降水相关的研究     

隋波  隋戈  隋丹 《地理科学》2007,27(Z1):69-77

探讨了副热带高压、西风带环流、极涡指数的年际和年代际变化规律,揭示了来自副热带、中纬度和极地的大气环流系统的强迫对中国夏季降水的影响.结果表明初夏,当纬向环流指数偏弱时,中国东北和华北大部分地区降水量偏多,这表明东亚中高纬地区盛行阻塞和冷涡偶极子系统,呈有利于东北的冷涡雨季形势;盛夏,西太平洋副热带高压脊线位置和亚洲区极涡强度指数与中国同期降水量场相关波列,均为自北向南呈"-、 、-、 "经向波列分布;春季亚洲区极涡强度、亚洲纬向环流指数、西太平洋副热带高压北界位置以及前一年冬季北半球极涡强度指数与盛夏中国降水量相关显著.中国盛夏降水带,从东北地区开始,由北向南分4个雨带.  相似文献   

气枪震源激发模式及应用   总被引：3，自引：5，他引：3  

罗桂纯  葛洪魁  王宝善  胡平  母红旺  陈颙 《中国地震》2007,23(3):225-232

气枪震源是一种重要的人工地震震源。气枪阵列理论的提出,使得气枪阵列设计技术日趋成熟,并能够在石油勘探和地球物理探测中得到更加广泛的运用。气枪震源在不同领域中应用时,需要不同的组合和激发模式,以适应不同的探测要求。加强主脉冲和加强气泡脉冲,是目前两种主要的气枪激发模式。通过比较研究两种气枪激发模式,讨论各种激发模式在激发时间、气枪间距、频率、分辨率等方面的差异,为气枪震源的广泛运用提供依据。  相似文献   

遥感和GIS技术在全球海面风速分析中的应用   总被引：5，自引：0，他引：5  

陈戈  方朝阳 《遥感学报》2002,6(2):123-128

将遥感技术和地理信息系统（GIS）技术相结合，建立了一个基于TOPEX卫星的全球海面风速分析的海洋地理信息系统（MGIS）。阐述了全球海面风速分析模型的建立方法，定义了描述风场特征的相关参数，介绍了全球海面风速海洋地理信息系统的结构、功能和工作流程，另外，对系统的3个应用实例进行了地学分析。  相似文献