The Texture,Mineral Assemblages and Origin of Metamorphic Peridotite from Kuda Ophiolite,Xinjiang

There are two grades of network-type texture in metamorphic peridotite from the Kuda ophiolite,Xinjiang,China,The first graduation consists of coarse-grained olivine with plastic deformation fabrics,orthopyroxene and minor clinopyroxene and Cr-spinel.The second graduation consists of small minerals filling among the mineral grains of the first graduation.Four kinds of assemblages containing tremolite have been discovered in the second graduation,which were formed during mantle partial melting and mantle metasomatism of a highly depleted peridotite.     

Attenuation of coda waves and Q c value beneath the Chengdu telemetered seismic network

Based on the single scattering model of coda power spectrum analysis, digital waveform data of 50 events recorded by the real-time processing system of the Chengdu telemetry network are analyzed to estimate the Q _c values of earth medium beneath the Chengdu telemetry network for several specified frequencies. It is found that the Q _c shows the frequency dependency in the form of Q _c = Q ₀ f ⁿ in the range of 1.0 to 20.0Hz. Estimated Q ₀ ranges from 60.83 to 178.05, and n is found to be 0.713 to 1.159. The average value of Q ₀ and n are 117 and 0.978 respectively. This result indicates the strong frequency dependency of the attenuation of coda waves beneath the Chengdu telemetry network. Comparing with the results obtained in other regions of the world, it is found that Q ₀ ⁻¹ value and its change with frequency are similar to those in regions with strong tectonic activity. This subject is supported by the Ministry of Personnel, China for partly sponsoring.     

PREDICTIONS OF CRUSTAL DEFORMATION CAUSED BY CHANGING POLAR ICE ON A VISCOELASTIC EARTH

Changes in polar ice could cause vertical crustal motion of up to several mm yr-1 along the edge of the Greenland and Antarctic ice caps. Measurements of the uplift could help constrain the changing ice volumes. The problem is complicated by the Earth's visco-elastic response to past loading, including the Late Pleistocene deglaciation. A method is described for removing these visco-elastic effects, by using simultaneous measurements of vertical motion and surface gravity. A linear combination of these two measurement types can be formed which is relatively independent of visco-elastic effects, and which can be interpreted in terms of present-day fluctuations in ice.     

安徽双河含柯石英硬玉石英岩中流体包裹体的研究

在安徽双河含柯石英石玉石英岩中已识别出５类流体懈裹体，其中早期退变质阶段捕获的包裹体是均一温度低、含盐度较高的水溶包裹体，晚期捕获提均一温度较高、含盐底低的水溶流体包裹体，更晚期的是三相富含ＣＯ２包裹体及均一温度高的气－液两相富Ｃ炮裹体，为限定硬玉石英岩的隆升轨迹提供重要依据，在单相气体包裹体和三相富含Ｃ炮裹体中的气相成分为ＣＯ２和Ｎ２，氮可能来自外部或玉石英岩的原岩。     

华北南部地区——古生界构造演化及其油气远景

华北南部地区的地质演化与华北其他地区一样，经历了结晶基底形成，中一晚元古代台内裂谷发育、古生代稳定地台沉积和中一新生代活化等发展过程。但本区受秦岭褶皱带构造活动的强列影响。因而具有相对独特的构造演化特征和油气控制条件。早寒武世中期，古秦岭海槽伸展扩张，沉积了一套全区广泛分布的以碳酸盐岩为主夹泥页岩的地层；晚寒武世开始，古秦岭海槽向北俯冲挤压，在本区南部出现一个平行于海槽的大陆边缘隆起；中奥陶世发生     

生态系统地震灾害初步研究

研究地震灾害的目的是为了保护人类.人类与周围的环境组成一个密不可分的系统,这个系统即生态系统.截止目前地震灾害的研究还局限在直观的人员伤亡和建筑物破坏,尚未涉及地震对生态系统的灾害影响,从而也未注意地震给人类带来的间接、众多、较长期的灾害影响.要真正保护人类免受地震灾害,就需要研究认识生态系统地震灾害.以人类为核心,按照构成生态系统的主体和环境因子的不同,可将生态系统由内向外、逐层包容地划分成社会生态系统、环境生态系统和自然生态系统三个层次类型.     

Study on distribution characteristics of strong earthquakes in Sichuan-Yunnan area and their geological tectonic background

Introduction Both Sichuan and Yunnan are provinces with more earthquakes. Based on catalogue of strong earthquakes in China compiled by the Prediction Department of China Earthquake Administration, there are 639 M5.0 earthquakes during 26 B.C.~A.D. 2001. Among them, 475 are M=5.0~5.9 events, 124 are M=6.0~6.9 events, 39 are M=7.0~7.9 events, and one is M=8 event occurred in Sichuan and Yunnan area. Here is one of the areas where seismic activities are most active in China. Sichuan-Yun…     

中强震与江苏新沂地震台地电阻率异常的关系研究

运用速率法、滑动富氏法对江苏省新沂地震台1990年至1999年地电阻率观测资料进行了分析，研究了电阻率异常与江苏省及其邻近地区的中强震的关系。结果表明．从1994年到1997年之间发生的中强震，新沂地震台地电阻率3个测向有不同程度的异常与之对应。研究结果表明．资料异常呈现出的各向异性和其对应性与地球自转加速年份、孕震期的应力状态、震区构造、介质结栖有关。     

多相地貌单元场地勘察中基岩与卵砾石、孤石的鉴别

在多相地貌单元场地勘察中，基岩与卵砾石的鉴别难度较大。应利用初步感性认识、钻进状态、岩样特征等多手段对基岩与卵砾石进行判别，以提高判别率。     

地质雷达在隧道检测中的应用

隧道施工完成后用常规方法很难对衬砌质量做出系统评价，地质雷达利用超高频脉冲电磁波探测目标介质的介电常数，很容易掌握砼衬砌结构的厚度、衬砌周围回填及空隙情况，围岩断层裂隙构造情况等，为工程技术评价提供依据。文章以实例，介绍了利用地质雷达对隧道进行检测所使用的仪器、工作参数及地质雷达资料处理解释步骤，并通过对几幅典型雷达图像进行分析介绍了不同异常结构在雷达剖面上的反映。