四川华蓥山花儿岩变形体特征及稳定性评价     

轩福华  周申立  刘泉 《四川地质学报》2004,24(4):226-228

阐述了花儿岩变形体的基本特征，分析了影响变形体的地质环境因素(包括地形地貌、地层结构和地下水)和外界影响因素(包括降水、人为活动和新构造运动)，以及变形体近期特征，并通过推力传递系数法和破坏概率分析法对变形体的稳定性进行了评价。  相似文献   

Criteria for initiation of motion of rigid bodies to base excitation     

C. C. Tung 《地震工程与结构动力学》2005,34(10):1343-1350

It is known that when an unanchored rigid body is placed on a horizontal base which oscillates horizontally, it may undergo one of four modes of motion: rest, slide, slide–rock and rock. Initiation of a rigid body into these modes depends on the slenderness ratio of the body, the coefficient of friction between the body and the base and the acceleration of the base. In this study, the coefficient of friction and the base acceleration are considered random. For specific probability distributions of the coefficient of friction and the peak base acceleration, and for various values of the mean and standard deviation of the two random variables, the probabilities of occurrence of these modes of motion are obtained for a body of given slenderness ratio. It is shown that randomness of the coefficient of friction and base peak acceleration should not be ignored. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

Dislocation structure of the crust-mantle boundary and low-velocity body within the crust beneath the Dabie Shan collision orogen     

LIU Qiyuan  Rainer Kind  CHEN Jiuhui  YUAN Xiaohui  LI Shuncheng  GUO Biao  Kurt Wylegalla & LAI Yuangen . State Key Laboratory of Earthquake Dynamics  Institute of Geology  China Earthquake Administration  Beijing  China  . GeoForschungZentrum Potsdam  Telegrafenburg A  Potsdam  D-  Germany 《中国科学D辑(英文版)》2005,48(7)

The Dabie Shan is located on the eastern side of the Qinling-Dabie orogenic belt, which marks a geological boundary between the Sino-Korean and Yangtze cra- ton. Since the 1980s, the discovery of coesite and mi- crodiamond in the Dabie Shan orogen motivates an extensive interest to the ultra-high pressure (UHP)metamorphism and its exhumation[1,2]. Many results about them were published, which deal with different disciplines, including tectonics, petrology and chro- nology[3?8]. Up to now,…  相似文献   

Small-scale mélange fabric between serpentinite block and matrix: Magnetic evidence from the Mitsuishi ultramafic rock body, Hokkaido, Japan     

Rie Morijiri  Mitsuru Nakagawa 《Tectonophysics》2005,398(1-2):33-44

The Mitsuishi ultramafic rock body in Hokkaido, Japan, consists mainly of serpentinized peridotites that originated from a depleted mantle. This study aims to show new evidence of small-scale mélange fabric of serpentinite matrix in the rock body. Each serpentinite block in the serpentine matrix shows large and stable intensities of natural remanent magnetization (NRM). However, the directions of serpentinite blocks' NRM in the matrix are randomly scattered. A Curie temperature (Tc) of 580 °C corresponding to pure magnetite was also observed. Additionally, there is no evidence of heating over 580 °C after serpentinization. The blocks in the matrix must have obtained crystallization remanent magnetization (CRM) during serpentinization. The directions of the blocks' characteristic remanent magnetization (ChRM) are also scattered. It shows that serpentinite blocks were magnetized prior to uplifting. The results of the study indicate that the magnetic carrier of the serpentinite blocks in the matrix is mainly composed of magnetite, and it can keep original magnetization before uplifting. The results also imply that the scattering directions of NRM indicate the presence of small-scale mélange fabric of serpentinite matrix.  相似文献   

人类活动对山地景观的影响研究进展   总被引：1，自引：0，他引：1  

角媛梅  张盼盼  胡文英 《云南地理环境研究》2006,18(5):38-42,57

提出山地景观是由相互联系的相对海拔较高的景观组分镶嵌构成的异质性镶嵌体，具有景观类型呈垂直地带性分布格局、多样性高、形状复杂及廊道曲度大等特点重点从斑块复杂性、景观稳定性和多样性以及组成单元间空间联系等方面评述了人类活动对山地景观结构的影响，说明人类活动可增加或降低景观斑块的复杂性，破坏山地景观的稳定性并可改变山地景观的多样性．分析了人类活动对景观功能及动态的影响，探讨了人类活动对山地景观影响的研究重点。  相似文献   

中国福建省亚热带山地4000年来植被变化的孢粉记录(英文)     

邱宏烈 《福建地理》2006,(3)

根据采自福建省中部戴云山脉亚高山水系源头地带(大致25°40′N,118°11′E)泥炭沉积洼地的孢粉纪录,对该地区亚热带山地植被近4000年来的变化进行了研究.孢粉记录和其他沉积资料显示,3个取样点的泥炭沉积开始于4000年前,很可能是全新世后期气候转冷的结果.在距今4000~1200年前期间,戴云山脉上部(海拔1300~1600m)的植被为亚热带针阔叶混交类型,优势种属包括Cryptomeria(柳杉)、Castanopsis(栲)、Quercus(栎)和Tsuga(铁杉)等.距今1200年前左右,该区域的植被发生了一次大的变化,表现在上述优势属种的孢粉在样品总孢粉数的比例突然下降,而Pinus(松),Gramineae(禾本科)以及Dicranopteris(芒萁)等属种的比例则提高了.这次剧烈的植被变化在其中的一个泥炭钻孔中留下了一层粘土记录,它代表了当时流域内植被受破坏后出现的严重土壤侵蚀.从泥炭沉积提取的孢粉记录还可以看出,研究区内广泛分布的松林是一种次生植被,它是人类不断干扰的结果.  相似文献   

绿色建筑的内涵及其发展的若干思考     

罗栋燊廖福霖  官巧燕郑国诜 《亚热带资源与环境学报》2006,1(2):84-87

随着我国城市化进程的快速推进，大规模的人居环境建设使我国的资源与环境面临巨大的挑战，发展绿色建筑已经成为可持续发展的重大战略问题．文章从可持续发展的角度，指出了绿色建筑的内涵与特征，并归纳了绿色建筑与一般建筑的区别．在此基础上，提出了发展绿色建筑的具体对策．  相似文献   

Undressing the researcher: feminism, embodiment and sexuality at a queer bathhouse event   总被引：2，自引：0，他引：2  

Alison L Bain  Catherine J Nash 《Area》2006,38(1):99-106

In this paper we examine how the researcher's body can be used as a tool for data collection in the process of ethnographic fieldwork. We focus in particular on the tensions inherent in undertaking embodied ethnographic research in the sexualized setting of a queer women's bathhouse event in Toronto, Canada. Our discussion addresses three moments within the research process: preparing our bodies to attend the bathhouse; positioning our bodies within the spaces of the bathhouse; and interacting with our bodies during the event. Through this discussion we argue that the body of the researcher is a contested site of knowledge production.  相似文献   

龙感湖沉积物中人类活动导致的营养盐累积通量估算^*   总被引：8，自引：9，他引：8       下载免费PDF全文

吴艳宏  王苏民 《第四纪研究》2006,26(5):843-848

通过LL-4孔沉积环境指标研究表明,近100年来龙感湖地区人类活动加强,导致营养元素磷、碳、氮以及铁在沉积物中的浓度均呈增长趋势,特别是1950年以来,随着大量人口的迁入,围湖造田、破坏湖滨湿地等造成水土流失加剧,沉积物质量累积速率加快,同时营养元素累积量急剧增加。根据营养元素与参比元素Al, Fe和Ti之间的关系,以及不同营养元素之间的相互关系,人类活动引起的累积量得以从自然背景上区分出来,结合沉积物质量累积速率计算,人类活动引起的磷、有机碳和氮的累积通量分别在151.0~889.4mg/m²a,4.3~149.0g/m²a和0.5~18.6g/m²a间变化。碎屑物质的累积稀释了沉积物中营养盐的富集浓度,龙感湖草型湖泊的特点,使湖泊沉积环境易于呈氧化环境,生物和地球化学作用,也削弱了人类活动累积营养盐的变化幅度,使沉积中营养盐呈平稳上升的趋势。  相似文献   

贵州矿产资源与人的生产生活     

武国辉  周其华 《矿产与地质》2006,20(1):94-96

贵州矿产资源丰富、分布广泛、门类齐全、矿种众多,是全国重要的矿产资源大省之一,通过了解贵州省的矿产资源分布概况、开发现状及其与人们生产、生活的密切联系,可为“富民兴黔”的经济战略目标提供参考。  相似文献