内蒙古二连浩特市—东乌珠穆沁旗半干旱荒漠草原区区域化探方法试验   总被引：5，自引：0，他引：5       下载免费PDF全文

孔凡吉  张青  曹金虎 《地质找矿论丛》2004,19(4):261-269

内蒙古二连浩特市-东乌珠穆沁旗地区属半干旱荒漠草原区.1∶20万区域化探扫面应针对该类景观区微景观特点,选择土壤或水系沉积物测量方法开展工作.经试验确定采样粒级为-5～ 20目;采样密度2个点/km2;采样介质为残坡积物或冲、洪积物.经4个1∶20万图幅的区域化探扫面工作,取得了明显的异常圈定和地质找矿效果,方法技术有效.  相似文献   

内蒙古大青山地区构造新样式初探     

杜菊民张庆龙  杜松金李洪喜赵世龙  解国爱 《江苏地质》2004,28(2):65-68

内蒙古大青山地区侏罗纪盆地中发育有断层相关褶皱，有十分清晰的断层传播褶皱，断层转折褶皱等构造样式。断层相关褶皱轴向呈东西向展布，形成褶皱的地层是早侏罗世右拐群煤系地层，表明该褶皱至少在煤层形成后，受南北向挤压应力作用形成。研究这一构造样式，对这一地区的推覆构造、盆山耦合研究具有重要地质意义。  相似文献   

岩石Kaiser效应测地应力原理中的若干问题研究   总被引：3，自引：0，他引：3  

刘峥  巫虹 《上海国土资源》2004,(3):38-41,56

该文通过对几种不同类型岩石的实验研究，提出了关于在围压条件下影响岩石Kaiser效应的若干问题，分析了它们的声发射特征，为深部地应力测量提供了一种新的解决方法。  相似文献   

辽西医巫闾山地区中生代两期韧性变形的研究   总被引：3，自引：0，他引：3  

张宏  王五力  李之彤  杨芳林  张立君  郑少林 《世界地质》2004,23(3):213-220

医巫闾山地区的韧性剪切构造是中生代两期韧性变形作用的产物。早期韧性变形中a线理发育,线理走向和糜棱面理走向基本一致,线理在xy面上的侧伏角绝大多数<30°;该期韧性变形是以左行走滑运动为主。晚期韧性变形中a线理发育,线理倾伏向和糜棱岩中糜棱面理倾向相近,线理在xy面上侧伏角主要在45°～90°之间;该期韧性变形是伸展作用的产物。医巫闾山中生代两期韧性剪切变形作用表明,在侏罗纪至早白垩世期间辽西地区不仅发生了强烈挤压推覆作用和伸展作用,也发生了大规模左行走滑作用。该韧性变形作用的发现对进一步研究辽西中生代的构造演化序列、期次和构造格架转换等问题有重要意义。  相似文献   

某水电站地下厂房硐室群岩爆预测与防治研究   总被引：2，自引：0，他引：2  

李攀峰  张倬元  刘宏  宋建波 《中国地质灾害与防治学报》2004,15(2):39-43

拟建某水电站的大型地下厂房硐室群处于中等偏高的地应力环境中，在前期的勘探过程中已发现一些与岩爆密切相关的地质现象。因此合理地评价其开挖过程中岩爆发生的可能性、岩爆的烈度、分布范围以及相应的预测防治措施具有重要的工程意义。基于此，文章首先从岩爆发生的基本条件、地质宏观评价的角度对硐室群施工过程中岩爆发生的可能性进行了评估；然后，分别采用定性方法和工程地质类比法对该地下硐室群岩爆发生的烈度进行了评价；进而根据三维有限元模拟结果对岩爆发生的部位进行了圈定。最后，针对所研究的地下硐室群的具体情况，提出了相应的防治措施，即加强监测和超前预报，并采用以围岩弱化为主，围岩强化为辅的治理措施。  相似文献   

承压水减压引起的沉降分析   总被引：7，自引：0，他引：7  

骆冠勇  潘泓  曹洪  尹小玲 《岩土力学》2004,25(Z2):196-200

由下卧承压水层减压引起的固结沉降计算与一般的由堆载或潜水位下降引起的固结沉降计算不同,本文着重研究了在深厚弱透水层下卧强透水承压层的复杂地质条件下,下卧承压水层减压引起的土中应力变化及周围地表沉降的计算方法;在假定一维竖向固结的条件下推导了减压引起的沉降固结度计算公式,该公式与常规的双向排水固结公式相同,表明排水减压固结与常规的双向排水固结有着相同的效果.最后,将此分析方法应用于潮州供水枢纽工程西溪水闸沉降分析中,实践的结果表明,该方法简单可行,能较好地满足工程要求.  相似文献   

Quasi-simultaneous VLBI and RATAN-600 observations of active galactic nuclei     

A. B. Pushkarev  Yu. Yu. Kovalev  I. E. Molotov  M. B. Nechaeva  Yu. N. Gorshenkov  G. Tuccari  C. Stanghellini  X. Hong  J. Quick  S. Dougherty  X. Liu 《Astronomy Reports》2004,48(11):900-908

VLBI observations of several quasars and BL Lacertae objects were carried out at 1.66 GHz in November–December 1999 using six antennas (Medvezh'i Ozera, Svetloe, Pushchino, Noto, HartRAO, and Shanghai). Maps of six sources (0420+022, 0420-014, 1308+326, 1345+125, 1803+784, and DA 193) obtained with milliarcsecond resolution are presented and discussed, together with their broad-band (1–22 GHz) spectra obtained on the RATAN-600 radio telescope at epochs close to those of the VLBI observations. Comparison of the VLBI maps with maps of these sources obtained on standard VLBI networks and with the RATAN-600 quasisimultaneous total-flux measurements indicates the reliability of the results obtained on this Low Frequency VLBI Network and the good efficiency of this network.  相似文献   

Continental crustal growth and the supercontinental cycle: evidence from the Central Asian Orogenic Belt   总被引：15，自引：0，他引：15  

Dawei Hong  Jisheng Zhang  Tao Wang  Shiguang Wang  Xilin Xie 《Journal of Asian Earth Sciences》2004,23(5):799

Studies of supercontinental cycle are mainly concentrated on the assembly, breakup and dispersal of supercontinents, and studies of continental crustal growth largely on the growth and loss (recycling) of the crust. These two problems have long been studied separately from each other. The Paleozoic–Mesozoic granites in the Central Asian Orogenic Belt have commonly positive Nd values, implying large-scale continental crustal growth in the Phanerozoic. They coincided temporally and spatially with the Phanerozoic Pangea supercontinental cycle, and overlapped in space with the P-wave high-V anomalies and calculated positions of subducted slabs for the last 180 Ma, all this suggests that the Phanerozoic Laurasia supercontinental assembly was accompanied by large-scale continental crustal growth in central Asia. Based on these observations, this paper proposes that there may be close and original correlations between a supercontinental cycle, continental crustal growth and catastrophic slab avalanches in the mantle. In this model we suggest that rapid continental crustal growth occurred during supercontinent assembly, whereas during supercontinental breakup and dispersal new additions of the crust were balanced by losses, resulting in a steady state system. Supercontinental cycle and continental crustal growth are both governed by changing patterns of mantle convection.  相似文献   

L'archivage des activités humaines par les neiges et glaces polaires : le cas du plomb     

Claude Boutron  Kevin Rosman  Carlo Barbante  Michael Bolshov  Freddy Adams  Sungmin Hong  Christophe Ferrari 《Comptes Rendus Geoscience》2004,336(10):847-867

The investigation of the occurrence of lead in dated snow and ice from Greenland and Antarctica has played a major role in our understanding of the history of the pollution of the atmosphere of our planet by this metal. Such studies have however proved to be very demanding, mainly because of the extreme purity of polar snow and ice. Reliable measurements can be obtained only if ultra-clean and highly sensitive procedures are used, as pioneered by Clair Patterson. The Greenland data show evidence of large-scale pollution of the atmosphere of the Northern Hemisphere for lead as early as two millennia ago during Greco–Roman times, especially because of mining and smelting activities in southern Spain. It peaked at the end of the 1960s, with lead concentrations in snow about 200 times higher than natural values, before declining during recent times because of the fall in the use of leaded gasoline. Lead pollution in Antarctica was already significant at the end of the 19th century as a consequence of whaling activities, the traffic of coal-powered ships crossing the Cape Horn, and mining activities in South America, South Africa and Australia. After declining because of the opening of the Panama Canal, the great economic depression and World War II, it reached a maximum during the 1980s, with lead concentrations 20 times higher than natural values. Other studies focus on past natural variations of lead in ancient ice dated from the last climatic cycles. To cite this article: C. Boutron et al., C. R. Geoscience 336 (2004).  相似文献   

2002年秋季山东省干旱遥感监测分析   总被引：2，自引：0，他引：2  

赵玉金  赵红  刘文  刘欣  张璇  薛晓萍 《国土资源遥感》2004,15(1):65-67,77

利用极轨气象卫星遥感资料对2002年山东省秋季干旱进行监测和服务,其监测方法主要采用热惯量法。为了提高土壤水分模式的计算精度,将全省分为4个区域,对利用卫星资料反演的地表温度日较差进行植被指数等环境因素订正。在地理信息系统支持下,比较准确地计算出农田受旱面积,效果良好。  相似文献