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91.
Zhang Xiaoliang 《中国地震研究》2004,18(2):161-170
On the basis of Discontinuous Deformation Analysis (DDA), and considering the moderate intrusion of specific block boundaries to different extents, the first-order block motion model is established for the northeastern margin of Qinghai-Xizang(Tibet) block and the kinematical model for depicting deformation of small regions as well by using GPS observations of three periods (1991, 1999 and 2001). By simulating, we obtained the motion features of the firstorder blocks between the large WWN faults on the sides of the studied region, the distribution features of the principal strain rate field and the inhomogeneous motion features with spacetime of the faults in the northern boundary of the Qinghai-Xizang (Tibet) block. 相似文献
92.
As a result of the left-lateral strike-slipping of the Altyn Tagh fault in Neotectonic period, a contra-rotational structure, namely the Zhaobishan vortex structure, has developed at the juncture of the main Altyn Tagh fault and the northern fringe fault of the Qilian Mountains.Preliminary analysis on the deformation and evolution of the Zhaobishan vortex structure. In combination with the previous data, suggests that the tectonic transform between the Altyn Tagh fault and the northern fringe fault of the Qilian Mountains attributes to the deformation of the rotational structure. The existence of a series of rotational structures along the Altyn Tagh fault and on the northeastern edge of the Qinghai-Xizang(Tibet) plateau indicate that as the substance in the northern Qinghal-Xizang (Tibet) plateau moves clockwise around the eastern tectonic knot of the Himalayas, rotational structures become the principal mode on the northern marginal zone of the Plateau of transforming and absorbing tectonic deformation. 相似文献
93.
9月全国大部地区降水量接近常年同期或偏少;四川、重庆等地出现大到暴雨、局地大暴雨天气;0421号热带风暴“海马”和第6号热带低压在我国登陆;黑龙江东北部、广西北部等地有旱情。月内,全国大部地区气温接近常年同期或稍偏高。 相似文献
94.
内蒙古"宝音图隆起"的归属讨论 总被引:5,自引:0,他引:5
对比研究表明,内蒙古“宝音图隆起”和狼山地区的古元古代宝音图岩群与新太古代色尔腾山岩群都是由中低级变质的各种片岩、大理岩组成,一致的岩石组合和变质相暗示二者可能是等同物而不是两个岩群。以物探资料为据的构造研究也证实,“宝音图隆起”与狼山地区之间并无槽一台级的大型断裂构造分开,二者实为统一的构造整体而不是分属槽台,只因两侧被两条近于平行的NE向断裂围限,使其总构造线方向呈NE或NNE向而与色尔腾山的构造线不同。结论认为,“宝音图隆起”仍是华北陆块的一部分,不属于内蒙古一大兴安蛉地槽褶皱系。 相似文献
95.
华南地区崩岗侵蚀灾害及其防治 总被引:9,自引:0,他引:9
刘瑞华 《水文地质工程地质》2004,31(4):54-57
根据区域调查和定位研究资料,介绍了华南地区崩岗侵蚀及其灾害特点,概述了崩岗的形成、发育规律及其演变过程,分析了崩岗侵蚀及其灾害的影响因素。提出进行崩岗灾害防治时,应在水土保持传统方法基础上,整合水文地质学和工程地质学及其它相关学科理论,应用GIS技术对崩岗侵蚀进行科学监测和管理,为坡地利用和环境整治以及灾害防治提供依据。 相似文献
96.
PENGRunmin ZHAIYusheng 《《地质学报》英文版》2004,78(2):534-547
Most ore-forming characteristics of the Langshan-Zha‘ertaishan hydrothermal exhalation belt, which consists of the Dongshengmiao, Huogeqi, Tanyaokou and Jiashengpan large-superlarge Zn-Pb-Cu-Fe sulfide deposits, are most similar to those of Mesoproterozoic SEDEX-type provinces of the world. The characteristics include: (1) All deposits of this type in the belt occur in third-order fault-basins in the Langshan-Zha‘ertaishan aulacogen along the northern margin of the North China Platform; (2) these deposits with all their orebodies hosted in the Mesoproterozoic impure dolomite-marble and carbonaceous phyllite (or schists) have an apparent stratabound nature; ores display laminated and banded structures, showing clear depositional features; (3) there is some evidence of syn-sedimentary faulting, which to a certain extent accounts for the temporal and spatial distribution and the size of the orebodies in all deposits and the formation of intrabed conglomerates and breccias; (4) they show lateral and vertical zonation of sulfides; (5) The Cu/(Pb Zn Cu) ratio of the large and thick Pb Zn Cu orebodies gradually decreases from bottom to top; and (6) barite is interbedded with pyrites and sometimes with sphalerite. However, some characteristics such as the Co/Ni radio of the pyrites, the volcanism, for example, of the Langshan-Zha‘ertalshan metallogenic belt, are different from those of the typical SEDEX deposits of the world. The meta-basic volcanic rock in Huogeqi, the sodic bimodal volcanic rocks in the Dongshengmiao and potassic bimodal-volcanic rocks with blastoporphyfitic and blasto-glomeroporphyritic texture as well as blasto-amygdaloidal structure in the Tanyaokou deposits have been discovered in the only ore-bearing second formation of the Langshan Group in the past 10 years. The metallogeny of some deposits hosted in the Langshan Group is closely related to syn-sedimentary volcanism based on the following facts: most of the lead isotopes in sphalerite, galena, pyrite, pyrrhotite and chalcopyrite plot on both sides of the line for the mantle or between the lines for the mantle and lower crust in the lead isotope composition diagram; cobalt content of some pyrites samples is much higher than the nickel content (Co/Ni= 11.91-12.19). Some volcanic blocks and debris have been picked out from some pyritic and pyrrhotitic ores. All Zn-Pb-Cu-Fe sulfide orebodies in these deposits occur in the strata overlying metamorphic volcanic rocks in the only ore-bearing second formation. In the Jiashengpan deposit that lacks syn-sedimentary volcanic rocks in the host succession only Pb and Zn ores occur without Cu ore, but in the Dongshengmiao, Tanyaokou and Huogeqi deposits with syn-sedimentary volcanic rocks in the host succession Cu ores occur. This indicates a relatively higher ore-forming temperature. The process of synsedimentary volcanic eruption directly supplied some ore-forming elements, and resulted in secular geothermal anomaly favorable for the circulation of a submarine convective hydrothermal system, which accounts for the precipitation of deep mineralizing fluids exhaling into anoxidic basins along the syn-sedimentary fault system in the Langshan-Zha‘ertai rift. The Dongshengmiao, Tanyaokou, and Huogeqi deposits hosted in the Langshan Group appear to be a transitional type of mineral deposit between SEDEX and VMS-types but with a bias towards SEDEX, while the Jiashengpan deposit hosted in the Zha‘ertai Group is of a characteristic SEDEX type. This evidence, together with other new discoveries of Mesoproterozoic volcanic rocks and the features of lithogeny and metallogeny of the Bayun Obo deposit in the neighborhood emphasize the diversity, complexity and uniqueness of the Mesoproterozoic Langshan-Zha‘ertal-Bayun Obo ore belt. 相似文献
97.
98.
华南发育一条近EW向展布的中侏罗世火山岩带, 福建永定盆地的"藩坑组玄武岩"是其中的典型代表之一. 藩坑玄武岩的TiO2为1.92 ~ 3.21 wt%, 属"高Ti玄武岩", 并有较高的全铁含量(11.09 wt%). 该玄武岩与东南沿海来自富集的岩石圈地幔的早白垩世玄武岩相比, 有完全不同的岩石地球化学特征: 相对富集Th, Nb, Ta, Zr和Ti等高场强元素, Zr/Ba, La/Nb, La/Ta, Zr/Y, Ti/Y, Ba/Nb, K/Ti和Rb/Zr等比值也与OIB相似; 除少数样品有较高εNd (T ) (1.87 ~ 3.55)外, 多数样品有类似球粒陨石的εNd (T)(-0.70 ~ 0.24), 属软流圈地幔来源并记录着软流圈与岩石圈相互作用的信息. 赣南、粤北、湘东南的(早-)中侏罗世玄武岩、辉长岩与福建藩坑玄武岩有相似的OIB型岩石地球化学特征. 这种OIB型玄武岩可作为该地区早中生代时期软流圈地幔上涌的岩石学标志. 软流圈地幔的上涌导致该地区构造伸展、裂谷盆地的形成. 相似文献
99.
2004年12月26日印度尼西亚苏门答腊地震是历史上破坏性最强的地震之一。此次地震的震级Mw=9.3(根据Stein和Okal以简正模式振幅修订,http://www.earth.northwestern.edu/people/seth/research/sumatra.html),是自1900年以来记录到的第二最大地震。它发生在苏门答腊岛北部以西100千米的近海处, 相似文献
100.
一、中国新时代控股(集团)公司的简况(一)历史沿革中国新时代控股(集团)公司是国资委直接管理的国有独资企业,成立于1980年,是当时国务院、中央军委批准成立的国防科技工业统一对外的窗口,主要任务是:发挥国防科技资源优势,促进军工技术的和平利用,促进科技成果商品化和产业化,促进军工产品进出口和国际经济技术合作。经过二十多年的发展,集团公司进一步突出主业,明确了集团定位是:立足国防军工,坚持军民结合,积极促进国防科技工业发展的综合服务经营型集团公司。集团公司的主营业务已形成了三大业务板块:一是以军品贸易为主体、军民品贸易… 相似文献