Important Geological Factors Controlling the Formation of Gold Deposits in East China     

徐克勤  倪培等 《中国地球化学学报》1997,16(1):1-7

The major gold deposits in east China are characterized by their occurrence in pre-Cambrian host metamorphic rocks,restriction in some specific stratigraphic-structural terranes,tendentious localization in ductile or ductile-brittle shear zones,association with the syntexis type granitoids,and significant remobilization,superimposition and enrichment by the later stage Mesozoic tectono-magmatic activities.  相似文献   

A new method of testing pile using dynamic P-S-curve made by amplitude of wave train     

Hu Yi-li  Xu Jun  Duan Yong-kong  Xu Zhao-yong  Yang Run-hai  Zhao Jin-ming 《地震学报(英文版)》2004,17(6):725-734

A new method of detecting the vertical bearing capacity for single-pile with high strain is discussed in this paper. A heavy hammer or a small type of rocket is used to strike the pile top and the detectors are used to record vibration graphs. An expression of higher degree of strain (deformation force) is introduced. It is testified theoretically that the displacement, velocity and acceleration cannot be obtained by simple integral acceleration and differential velocity when long displacement and high strain exist, namely when the pile phase generates a whole slip relative to the soil body. That is to say that there are non-linear relations between them. It is educed accordingly that the force P and displacement S are calculated from the amplitude of wave train and (dynamic) P-S curve is drew so as to determine the yield points. Further, a method of determining the vertical bearing capacity for single-pile is discussed. A static load test is utilized to check the result of dynamic test and determine the correlative constants of dynamic-static P(Q)-S curve. Foundation item: Key projects of the tenth Five-year Plan of Yunnan Province (documented Yunnan district [2002]54-02-02) and Geophysical Society of Yunnan Province.  相似文献   

天津盛夏降水趋势与初夏华北高压的统计分析   总被引：3，自引：1，他引：3  

周鸣盛段丽瑶  周梁丹 《气象科技》2004,32(6):482-484

根据初夏(6月)的天气气候演变，预测盛夏(7～8月)的短期气候趋势，一直是急需解决的难题。文章揭示了自1958年以来天津盛夏降水趋势与初夏时节临近地区上空的环流特征之间的统计关系。结果表明，初夏华北高压强时盛夏天津降水偏少，反之盛夏天津降水偏多，不仅逐年的对应关系显著，而且变化趋势相反，转折时期也一致。初步解释了20世纪70年代以前天津(华北)盛夏多雨和80年代至今天津(华北)少雨的物理原因。以此为主要根据建立了初夏对于盛夏天津降水的短期气候预测方法，1998～2003年连续6年预报正确。  相似文献   

青藏高原影响亚洲夏季气候研究的最新进展   总被引：40，自引：6，他引：40  

吴国雄  毛江玉  段安民  张琼 《气象学报》2004,62(5):528-540

文中回顾了近 10a来吴国雄等在青藏高原影响亚洲夏季气候研究方面的最新进展。通过分析东西风交界面的演变证明 ,由于青藏高原的春季加热 ,亚洲季风区对流层低层冬季盛行偏东风转变为夏季偏西南风最早发生在孟加拉湾东部 ,与其相伴随的激烈对流降水出现在其东面。因此孟加拉湾东部至中印半岛西部是亚洲季风最早爆发的地区。同时也指出盛夏伊朗高原和青藏高原加热所激发的同相环流嵌套在欧亚大陆尺度的热力环流中 ,从而加强了东亚的夏季风 ,加剧了中西亚的干旱 ;并通过其所激发的波动对夏季东亚的气候格局产生重要影响。文中还比较了夏季南亚高压的伊朗模态和青藏模态性质的异同及其对亚洲夏季降水异常分布的不同影响。  相似文献   

Recent progress of glaciological studies in China     

LIU Shiyin  WANG Ninglian  DUAN Keqin  XIAO Cunde  DING Yongjian  HAN Haidong 《地理学报(英文版)》2004,14(4):401-410

1IntroductionIn the early 1960s, glaciers in western China were classified into maritime- and continental-types by different glacial environment and physical characteristics (Shi and Xie, 1964). With extensive glaciological investigations in the western regions (Lanzhou Institute of Glaciology and Geocryology of CAS, 1988), Lai and Huang (1990) suggested a new classification of temperate, subpolar and quasipolar glaciers, corresponding to the maritime-, subcontinental- and extremely contin…  相似文献   

Recent progress of glaciological studies in China     

LIU Shiyin  WANG Ninglian  DUAN Keqin  XIAO Cunde  DING Yongjian  HAN Haidong 《地理学报》2004,14(4):401-410

Glacier inventory compilation during the past 20 years and modifications of that for the Eastern Pamir and Banggong Lake indicate that there are 46,342 modern glaciers with a total area and volume of 59415 km2 and 5601 km3 respectively in China. These glaciers can be classified into maritime and continental (including sub-continental and extremely continental) types. Researches show that glaciers in China have been retreating since the Little Ice Age and the mass wastage was accelerated during the past 30 to 40 years. Being an important part of glaciological studies in China, ice core climatic and environmental studies on Tibetan Plateau and in the Antarctica have provided abundant, high resolution information about past climatic and environmental evolution over the Tibetan Plateau and Antarctica. Except for different parameters recorded in ice cores relating to climate and environment changes on Tibetan Plateau, records from ice cores extracted from different glaciers show that the discrepancies in climatic and environmental changes on the north and south parts of the plateau may be the consequence of different influencing effects from terrestrial and solar sources. Glaciological and meteorological phenomena imply that Lambert Glacier valley is an important boundary of climate in the east Antarctica, which is thought to be connected with cyclonic activities and Circum-polar Waves over the Antarctica.  相似文献   

宝鸡市气候服务系统          下载免费PDF全文

李建芳  李建军  郭清厉 《山西气象》2005,(2):15-16

本文首先给出了雨水集蓄利用的概念，针对黄土高原地区十分匮乏的水资源和严重的水土流失现状，提出了在该区实施雨水集蓄的可行性。在此基础上，对雨水集蓄利用在各个方面所取得的成就和存在的问题，进行了深入细致的分析，并对亟待解决的问题和今后的发展方向进行了展望。  相似文献   

不同降水天气系统自然降水特征及火箭人工增雨潜力分析   总被引：4，自引：1，他引：4  

吴志会  段英  张晶  石立新 《气象科技》2005,(Z1)

统计分析了1981~2000年20年中15种降水天气系统影响下河北地区自然降水特征,并对火箭人工增雨的潜力进行了初步分析。统计分析表明:西来槽类、高空低涡类、冷锋、切变线和副高后部等天气系统是影响河北地区的主要降水系统,其降雨量和降雨日数占到了90%以上;不同的天气系统在不同季节对降水的贡献有所不同,其中西来槽类的降雨量和降雨日数均居首位,开展人工增雨催化作业机会最多;夏季降水系统最强,云水资源最为丰富,人工增雨潜力很大,是开展火箭人工增雨催化作业的最佳季节,春秋两季增雨潜力明显比夏季小,冬季最小;倒槽、副高后部、台风低压、高空低涡类和气旋类等系统最强,日降雨量和单位面积降雨量明显比其它系统大,尤其对蓄水型火箭增雨作业十分有利。  相似文献   

青西油田碳酸盐岩裂缝性储层地球物理预测技术的应用     

师永民撒利明  陈广城田鑫李虹  王斌婷 《应用地球物理》2005,2(2):119-126

白云岩成岩收缩晶间孔、洞、缝与构造网状缝相互沟通可以组成良好的油气储层，但是这种复杂裂缝—孔隙型储层分布随机性强、发育程度和差异性大，储层预测难度大。本文以中国西部酒泉盆地青西油田下白垩统下沟组湖相白云岩裂缝—孔隙型储层为例，提出地球物理综合预测碳酸盐岩裂缝的方法。本文描述了综合地球物理方法预测碳酸盐岩裂缝储层的实施和应用效果。  相似文献   

2-D crustal Poisson’s ratio from seismic travel time inversion in Changbaishan Tianchi volcanic region   总被引：1，自引：0，他引：1  

Liu Zhi  Zhang Xian-kang  Wang Fu-yun  Duan Yong-hong  Lai Xiao-ling 《地震学报(英文版)》2005,18(3):345-353

Based on the inversion method of 2D velocity structure and interface, the crustal velocity structures of P-wave and S-wave along the profile L ₁ are determined simultaneously with deep seismic sounding data in Changbaishan Tianchi volcanic region, and then its Poisson’s ratio is obtained. Calculated results show that this technique overcomes some defects of traditional forward calculation method, and it is also very effective to determine Poisson’s ratio distribution of deep seismic sounding profile, especially useful for study on volcanic magma and crustal fault zone. Study result indicates that there is an abnormally high Poisson’s ratio body that is about 30 km wide and 12 km high in the low velocity region under Tianchi crater. Its value of Poisson’s ratio is 8% higher than that of surrounding medium and it should be the magma chamber formed from melted rock with high temperature. There is a high Poisson’s ratio zone ranging from magma chamber to the top of crust, which may be the uprise passage of hot substance. The lower part with high Poisson’s ratio, which stretches downward to Moho, is possibly the extrusion way of hot substance from the uppermost mantle. The conclusions above are consistent with the study results of both tomographic determination of 3D crustal structure and magnetotelluric survey in this region. Foundation item: Key Project from China Earthquake Administration and the Project (95-11-02-01) from Ministry of Science and Technology (2001DIA10003). Contribution No. RCEG200401, Geophysical Exploration Center, China Earthquake Administration.  相似文献