Crust-Mantle Electrical Structure in the Area along the Yadong-Burn Co Profile     

WEI Wenbo  CHEN Leshou  TAN Handong  DENG Ming 《Continental Dynamics》1997,(1)

1.IntroductionUntilnowTibetisstillthearchetypalregionwithcontinentalcollisiongoingoninit,henceitisanidealnaturallaboratoryforstudyingthegeologicevolutionofintracontinentalorogenicbeltandthecrust-mantledeepprocesses,aswellastheinteractionbetweenthemandthesupracrustalmovements.Forthisreason,forseveraldecadesgeologistsandgeophysicistsfromvariouscountrieshavemadeunremittingeffortsinthisregiontoprobeintotheoriginandprocessoftheplateauformation,withavarietyofcognitionsproposed.TheCMPresultsoftheSi…  相似文献   

The phytoplankton of some saline lakes in Central Asia     

Yoshiko Kawabata  Hiroyuki Nakahara  Yukio Katayama  Norio Ishida 《International Journal of Salt Lake Research》1997,6(1):5-16

The Aral Sea, Lake Balkhash, and Lake Kamyslybas are closed lakes in Central Asia. They range from oligosaline to metasaline. The salinity of the Aral Sea has increased by more than 30 g L⁻¹ since widespread irrigation began in its catchment area. Few studies of the phytoplankton have been conducted on these lakes since extensive irrigation started. The investigation reported here compares the flora of phytoplankton in these saline lakes. In the Small Aral Sea, phytoplankton density gradually decreased with increasing electrical conductivity (EC) (∼ salinity), but there was no such relation in Lake Balkhash and Lake Kamyslybas. In the Aral Sea, Dinophyceae and Bacillariophyceae were frequently observed in most areas of high EC value, and Cyanophyceae were most conspicuous in the area of medium and lower EC values. In Lake Balkhash, Cyanophyceae were most conspicuous, but Chlorophyceae were also noticeable. Most Cyanophyceae in Aral Sea formed filaments with heterocysts. The distinct characteristic of the phytoplankton of the Lake Balkhash was that all dominant species form colonies covered with a gelatinous film. Siliceousplankton diversity gradually decreased with increasing EC values in the Aral Sea and Lake Balkhash.  相似文献   

Analysis of rotational invariants of the magnetotelluric impedance tensor   总被引：1，自引：0，他引：1  

L. Szarka  M. Menvielle 《Geophysical Journal International》1997,129(1):133-142

  相似文献   

山西奇村地热田的勘察与研究   总被引：2，自引：0，他引：2  

张瑞丰  肖建华 《地质论评》1996,42(5):475-480

通过近期对山西省忻州市奇村地热田进行的实地物化探勘察发现：地下热水的分布范围内视电阻率普遍偏低，且水温愈高，视电阻率愈低，在α 卡异常处均有地下热水存在。该地热田的热水分布区内的隔水层和盖层为亚粘土，粘土层。基地下热水的水化学类型为氯化物硫酸钠型及氯化钠型，热田热水赋存和滞留于浅层次生热储内。  相似文献   

多电极直流探测系统及其应用效果   总被引：2，自引：0，他引：2  

李志武  周燕云  刘永东  贺宁波 《物探与化探》1996,20(6):461-470,473

本文介绍地质矿产部机电所研制的多电极直流探测系统的主要技术性能,硬件和软件设计特点,数据处理软件的配置以及在不同领域勘探应用实例。  相似文献   

0.25—3.75GPa和20—370℃条件下0.025molNaCl溶液电导率研究          下载免费PDF全文

郑海飞  谢鸿森 《地质学报》1997,71(3):274-280

在０．２５－３．７５ＧＰａ和２０－３７０℃条件下测量了ＮａＣｌ溶液的电导率。结果表明（１）电导率随温度增高而增大，且电导率的对数与温度的倒数为线性关系，但不同压力不其斜率不同。（２）电导率与压力的 关系较为复杂，存在着不连续性。即在２．２５－３．３７ＧＰａ压力范围，电导率随压力增大而增大；在１．２５－２．００ＧＰａ压力范围，电导率与压力几乎无关；０．７５ＧＰａ压力的电导率高于相邻力的电导率。上述。  相似文献   

Conductivity of NaCl solution at 0.4–5.0 GPa and 25–500 °C     

Yousheng Xu  Hongsen Xie  Jie Guo  Haifei Zheng  Yueming Zhang  Maoshuang Song 《中国科学D辑(英文版)》1997,40(4):398-402

NaCI-H₂O is the most fundamental ternary system in geology. Until now, the measurements of electrical conductivity of NaCl solutions are still little at high pressures (> O.5 GPa) We measured the conductivity of 0.01 m NaCl solution at 0.4–5.0 GPa and 25-500°C. The results are consistent with that of Quist and Marshall (1968) at 0.4 GPa. The conductivity of NaCl solution increases with increasing temperature. The results also show that the conductivity of NaCl solution changes little with increasing pressure below 1.5 GPa and changes rapidly with increasing pressure above 1.5 GPa. The rapid increase of the conductivity of NaCl solution may play an important role in many geological processes (such as the genesis of ore deposits under hydrothermal condition) and other fields. Project supported by the National Natural Science Foundation of China.  相似文献   

电吸附找矿方法   总被引：3，自引：2，他引：3  

周奇明  周立宏  董树政 《物探与化探》2004,28(3):199-201

电吸附找矿方法是找隐伏矿的新方法。它是指通过物理化学手段来发现后生地球化学异常的找矿方法。它是建立在异常元素地球化学理论和野外地电提取法的理论基础之上。利用电吸附找矿方法在一些已知矿床进行找矿效果试验,获得了很好的效果,说明了该方法找矿的有效性。  相似文献   

电法在探测岩溶上的应用     

武斌  曾校丰 《四川地质学报》2004,24(4):251-253

通过对电法中几种常用方法的分析，说明其在岩溶探测中有效，并提出了七种确定岩溶的方法。  相似文献   

Problems of the solution: intervention into small-scale irrigation for drought proofing in the Mekele Plateau of northern Ethiopia     

Yohannes Aberra 《The Geographical journal》2004,170(3):226-237

The Mekele Plateau, located in the semi-arid northern highland region of Ethiopia, is a drought-prone, highly degraded area. It has long been neglected by policymakers and thus recurring famine, widespread poverty, armed conflicts and mass outmigration have contributed to the near collapse of the farming systems and the livelihoods of the population. Traditional stream diversion irrigation has been practised in this area for several centuries. The systems of water management in particular may be considered inappropriate owing to the need for thriftiness in water use imposed by the local environment. The systems of headworks and canals are crude and wasteful on water. Recent interventions to improve the small-scale irrigation systems of the area have not been successful. Most interventions have preferred to introduce rainwater harvesting systems using micro-dams rather than trying to upgrade the traditional diversion schemes. Evaluation of irrigation structures in the field, interviews with key informants in government, analysis of documents and discussions with irrigators indicate that both the Ministry of Agriculture and SAERT-Commission's rainwater harvesting programmes have generally failed. The case of the most recent intervention by SAERT has failed because of myopic project planning, inadequate engineering studies, unsound designs, too short a time for implementation, and lack of full farmer involvement at different levels of project planning and implementation.  相似文献