青海拉鸡山构造带是裂谷还是构造窗——与王二七研究员商榷   总被引：2，自引：0，他引：2       下载免费PDF全文

左国朝  李志林等 《地质论评》2001,47(6):561-566

拉鸡山构造带东西长逾650km,展布于由元古宇组成的结晶地块内部，是一条早古生代火山岩极为发育的构造带。长期以来众多学者对拉鸡山进行大地构造学、岩石学研究。作者曾在拉鸡山从事多年野外调查工作，研究认为该地区无论在区域地质学、岩石学、构造变形学还是在大地构造演化方面其早古生代构造演化史皆具典型的裂谷带特征。晚古生代以来，经历了陆内多阶段造山过程，而为后期多阶段抬升的构造窗观点值得商榷。  相似文献   

Study on the relationship between geothermal exploitation and seismic activity in Xi’an region     

Wu Fu-chun  Song Li-sheng  Zhu Xing-guo  Wang Feng  Jing Bei-ke  Dong Xing-hong  Fang Wei  Zuo Yong-qing 《地震学报(英文版)》2001,14(4):434-439

Based on the analysis of the induced earthquakes in China and abroad, we get some ideas about earthquakes induced by pumping water out of a well or injecting water into a well. The induced earthquakes usually occur near the well, and they are generally small earthquakes. The earthquake sources are shallow, and they belong to the main shock-after shock type of earthquake or the swarm-type of earthquake. The magnitude and the quantity of the induced earthquakes obviously depend on the pressure and the quantity of water pumped or injected. These earthquakes happen as soon as pumping or injecting occurrence, or after ten or twenty days, they may occur at the time of injecting mud or injecting high pressure water when a well is being drilled, or at the time when the ground water is being normally exploited. A large quantity of hot water has been exploited since 1990 in Xi’an, and the quantity of water exploited has been increasing year by year, as a result the groundwater level has been dropping with the water pumped out and the water level is high in summer and low in winter. The earthquakes in Xi’an region belong to the solitary-type and they spread outside Xi’an city where the wells are concentrated but no earthquake happens. The seismic frequency and the energy released have no relation with the quantity of water exploitation or the water level in the well. It is considered that geothermal exploitation does not induce earthquakes in and around Xi’an because of its specially geological condition. Foundation item: Project sponsored by the Landslide Office of Shaanxi Province and Society of Disaster Reduction of Shaanxi Province.  相似文献   

THE CHARACTERS OF ENERGY BUDGET ON THE GOBI AND DESERT SURFACE IN HEXI REGION   总被引：23，自引：0，他引：23       下载免费PDF全文

胡隐樵  杨选利  张强  左洪超 《Acta Meteorologica Sinica》1992,(1)

In the paper,the characters of surface energy budget on Huayin(Gobi)and the desert surface during the periodfrom 26 June to 31 August 1990 in the HEIFE have been analyzed,then have been compared with the observed resultsduring 4—19 September 1988 in the Pilot Observation Period of the HEIFE.The results show that the atmosphere is insuperadiabatic unstable state and there is a phenomenon of inverse humidity to form negative water vapour flux.Thesensible heat flux on the surface energy budget is in majority,but the latent heat flux may be neglected over the Gobi anddesert surface in the cloudless daytime in the summer.  相似文献   

THE CHARACTERS OF ENERGY BUDGET ON THE GOBI AND DESERT SURFACE IN HEXI REGION^*          下载免费PDF全文

Hu Yinqiao  Yang Xuanli  Zhang Qiang  Zuo Hongchao 《Acta Meteorologica Sinica》1992,6(1):82-91

In the paper,the characters of surface energy budget on Huayin(Gobi)and the desert surface during the period from 26 June to 31 August 1990 in the HEIFE have been analyzed,then have been compared with the observed results during 4-19 September 1988 in the Pilot Observation Period of the HEIFE.The results show that the atmosphere is in superadiabatic unstable state and there is a phenomenon of inverse humidity to form negative water vapour flux.The sensible heat flux on the surface energy budget is in majority,but the latent heat flux may be neglected over the Gobi and desert surface in the cloudless daytime in the summer.  相似文献   

甘蒙北山中南带新发现燕山早期走滑挤压推覆构造带   总被引：5，自引：0，他引：5       下载免费PDF全文

左国朝  郑亚东 《地质科学》1992,(4):309-316

近年来在区域调查基础上,于甘蒙北山中南带首次发现了六条由南向北推覆的构造带,在每个推覆陶造带边缘发育大小不一的飞来峰。推覆体走向近东西,推覆在震旦系至中、下侏罗统之上,最大直观推覆距达55km,累积推覆距大于150km,并被上侏罗统不整合覆盖,形成时代为燕山早期。  相似文献   

甘蒙北山—东疆天山元古代古陆壳特征及其早古生代地壳类型   总被引：2，自引：1，他引：2  

左国朝  李茂松 《甘肃地质》1992,1(1):55-67

本文研究了甘蒙北山及东疆天山早古生代地壳类型,划分为元古代的古陆壳、早古生代洋壳、拉张型过渡壳、汇聚型过渡壳。早古生代沿着库米什—卡瓦布拉克—星星峡—小黄山一线自震旦世晚期由东向西逐渐开裂,于晚寒武世至早奥陶世全面打开,形成库米什—小黄山洋盆。其北侧由塔里木古板块北缘分离出中天山微大陆。且末断裂带斜贯全区,起了控制东西两侧构造发展的转换断层作用。甘蒙北山较东疆天山的地壳类型更为复杂,先后发育有奥陶纪拉张型过渡壳—裂谷带和志留纪汇聚型过渡壳—沟弧盆体系。晚古生代全区构造演化进入开合交替时期,其开时形成拉张过渡壳,早古生代洋区在库鲁克塔格北缘哈孜布拉克塔格地区延续到泥盆—石炭纪。  相似文献   

祁连山蛇绿岩型超镁铁岩铬铁矿床成矿的主要特征   总被引：4，自引：0，他引：4  

苟国朝  田培昭等 《甘肃地质》1993,2(1):35-45

祁连山造山带目前已发现不同规模的超镁铁岩体（群）1000余个,产有铬铁矿床（点）和矿化点80余处,这些岩体及其矿产主要产在北祁连优地斜增生地体边部的海沟带中,少数产在祁连中间地块的边部。岩体成因类型为蛇绿岩组合中的超镁铁质单元,铬铁矿的富集部位是地幔橄榄岩和堆积杂岩带底部的纯橄榄岩。岩石多为铝过饱和系列,岩体的平均化学成分接近于斜辉橄榄岩;Cr₂0₃的平均含量大于0.40％,Al₂0₃的平均含量近于或者大于1％。铬尖晶石的化学参数特征反映出低铁富镁的介质对形成富铬尖晶石是有利的。富铬岩体中Cr、Co、Ti、V的含量较高。  相似文献   

Some Phenomena of the Interaction Between Vegetation and a Atmosphere on Multiple Scales     

胡隐樵  陈晋北  郑元润  李国庆  左洪超 《大气科学进展》2006,23(4):639-648

This article studies the response of the distribution pattern and the physiological characteristics of the ecosystem to the spontaneous precipitation and the interaction between vegetation and the atmosphere on multiple scales in arid and semi-arid zones, based on measured data of the ecological physiological parameters in the Ordas Plateau of northern China. The results show that the vegetation biomass and the energy use efficiency of photosynthesis are especially sensitive to the annual precipitation; strong and complex interactions exist between the vegetation and the atmosphere on multiple scales leading to supernormal thermal heterogeneity of the underlying surface, the strong vortex movement and turbulence. This study can facilitate understanding of the land surface processes and the influences of global climate change as well as human activities on the human environment in the arid and semi-arid zones. It also aids in improving the parameterization schemes of turbulent fluxes of a heterogeneous underlying surface for land surface processes in climate models.  相似文献   

电离层对台风响应的全过程的特例研究   总被引：8，自引：0，他引：8       下载免费PDF全文

肖赛冠  郝永强  张东和  肖佐 《地球物理学报》2006,49(3):623-628

作为特例研究，本文对1988年和1990年两次强台风影响期间的电离层多普勒记录及相应的台风资料进行了细致的相关分析，目的是利用多普勒记录的连续性优点来了解电离层对登陆（或近海）强台风通过声重波响应的演化全过程.分析表明，在这两次台风影响期间，电离层形态中除有明显的波状扰动（中尺度声重波）出现外，还有一些值得注意的新现象：波动的时间演化表现出明显的幅度逐渐增加以及频率由高频向低频转变，在振幅很大的情况下日落后同时出现扩展F（Spread F）现象，显示了声重波在激发电离层不规则结构方面的种子作用.这一演化过程与电离层中TIDs的线性传播理论一致，文中开展了对这一现象的非线性数值模拟，模拟结果基本上也与上述观测现象相吻合.  相似文献   

“资源一号”卫星星内粒子探测器对扰动事件的观测   总被引：4，自引：2，他引：4       下载免费PDF全文

邹鸿  肖佐  郝永强  邹积清  仲维英  吴中祥  向宏文  朱文明 《地球物理学报》2006,49(3):636-641

本文比较了在太阳平静和扰动时期“资源一号”卫星星内粒子探测器对卫星舱内高能粒子的观测结果，发现在平静时期观测结果很好地反映了辐射带高能粒子在该高度上的分布情况.在扰动时期，粒子探测器观测到高能粒子分布出现重大变化，本文进一步讨论了影响高能粒子在近地空间分布的可能因素.  相似文献