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991.
Abstract: Landslide research at the British Geological Survey (BGS) is carried out through a number of activities, including surveying, database development and real-time monitoring of landslides. Landslide mapping across the UK has been carried out since BGS started geological mapping in 1835. Today, BGS geologists use a combination of remote sensing and ground-based investigations to survey landslides. The development of waterproof tablet computers (BGS·SIGMAmobile), with inbuilt GPS and GIS for field data capture provides an accurate and rapid mapping methodology for field surveys. Regional and national mapping of landslides is carried out in conjunction with site-specific monitoring, using terrestrial LiDAR and differential GPS technologies, which BGS has successfully developed for this application. In addition to surface monitoring, BGS is currently developing geophysical ground-imaging systems for landslide monitoring, which provide real-time information on subsurface changes prior to failure events. BGS’s mapping and monitoring activities directly feed into the BGS National Landslide Database, the most extensive source of information on landslides in Great Britain. It currently holds over 14?000 records of landslide events. By combining BGS’s corporate datasets with expert knowledge, BGS has developed a landslide hazard assessment tool, GeoSure, which provides information on the relative landslide hazard susceptibility at national scale. 相似文献
992.
Geology, Geochemistry and Minerogenesis of the Shijuligou Zinc–Copper Deposit in Gansu, China 总被引:1,自引:0,他引:1
LI Wenyuan DENG Jun GAO Yongbao GUO Zhouping ZHANG Zhaowei SONG Zhongbao 《《地质学报》英文版》2009,83(6):1052-1063
Abstract: The Shijuligou deposit was separated by an arcuate ductile shear zone cross the center of the deposit region, resulting in the difference between the southern and northern ore bodies. The lead (Pb) isotopic data of ores of the Shijuligou copper deposit have averages of 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb in 17.634, 15.444, and 37.312, respectively. It has been shown that ore-forming metals originated from intrusive and extrusive rocks in the upper part of ophiolites. The sulfur isotopic data of pyrite and chalcopyrite in the northern part change from +7.61‰ to +8.09‰ and +4.95‰ to +8.88‰ in the southern part. Isotopes of δ18O in the Shijuligou copper deposit are between +11.1‰ and +18.6‰, with the calculated δ18OH2O at +0.65‰. It is suggested that the mineralized fluid is a mixture of magma fluid, meteorological water, and seawater through circulating and leaching metals from the volcanic rocks. The zircon uranium-lead (U–Pb) dating of gabbro is 457.9±1.2 Ma, and the lower crossing age of the discordant and concordia curves of pyroxene spilite of zircon is 454±15 Ma. It is indicated that the Shijuligou deposit formed in a new ocean crust (ophiolite) of the back-arc basin in the late Ordovician. Mineralization should occur in the intermittence period after strong volcanic activity, and the age should be the late Ordovician. Moreover, the mineralization of ophiolite-hosted massive sulfide deposits in the ancient orogenic belt of the late Ordovician in the northern Qilian Mountains was controlled by the primary fault/fracture, with the forming of a metallogenic hydrothermal system by a mixture of volcanic magma fluid and seawater, which circularly leached the metallogenic metals from the volcanic rocks, resulting in their accumulation. The ore bodies were transformed with morphology and metallogenic elements. Jasperoid is an important sign for prospecting such deposits. There were many island arcs in the continent of China. This study provides evidence for understanding and exploration of ophiolite-hosted massive sulfide deposits in western China, especially in the area of northern Qilian Mountains. 相似文献
993.
Caterina RINAUDO Daniela GASTALDI Orfeo ZERBINATI Elisa FORNERO Graziella BERTA 《《地质学报》英文版》2009,83(6):1224-1231
Abstract: Twenty-four soil samples were collected at three depths from an approximately 2.5 acre contaminated site in southern Piedmont (Italy) and then analyzed. The main soil parameters determined were: pH, Cation Exchange Capacity (CEC), particle size distribution, total organic carbon (TOC) content and retained metal concentration. The mineral phases were identified by X-Ray Powder Diffraction (XRPD). All of the samples contained Zn and Cu resulting from industrial contamination during the last century, and those obtained at depths of 20-40 cm consistently showed the highest levels. To determine which size fraction was most active in the retention process, the samples were separated into four fractions (≤2 mm, ≤63 μm, ≤30 μm and ≤2 μm) and the amount of pollutant measured in each. It was found that metal retention was the highest in the clayey fraction, whose clay minerals were identified by XRPD after K+ and Mg2+ saturation, glycerol treatment and heating to 550°C. The clayey fraction was also the richest in TOC, and a direct correlation between TOC amount and metal retention was observed. 相似文献
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995.
A型花岗岩的研究进展及意义 总被引:34,自引:4,他引:30
A型花岗岩主要形成于伸展的构造背景中,是构造环境识别的重要岩石学标志之一。由于形成于特殊的构造背景和重要的地球动力学意义,A型花岗岩的研究一直得到广泛的关注,但是仍旧有许多问题(如命名、分类和成因等)在争论之中。本文从下面几个方面对A型花岗岩的研究现状进行了较系统的总结:(1)A型花岗岩的概念及特征;(2)A型花岗岩与高分异I、S型花岗岩的区别;(3)A型花岗岩的物质来源及成因模式;(4)A型花岗岩的实验岩石学成果;(5)A型花岗岩的分类;(6)A型花岗岩的构造背景及动力学意义。A型花岗岩在形成过程中斜长石、斜方辉石可能为主要的残留或分离结晶矿物相。除了传统的A1(非造山)、A2(后碰撞)分类外,"还原型"和"氧化型"的分类方案最近也受到广泛关注。 相似文献
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流体包裹体研究:进展、地质应用及展望 总被引:8,自引:1,他引:7
在多数地质作用过程中,流体都担任着元素迁移的载体、化学反应的活化荆的角色.大量研究表明,岩石、矿物以及元素在有无流体的情况下会表现出迥异的物理和化学性质,所以对于认识某一地质过程而言,流体方面的研究往往能够提供极其重要的信息.流体包裹体则以其直接反映古流体的成分,在各种矿物中的普遍存在性,以及对各种后期改造有一定的抵抗力等特点而成为研究古地质流体的最佳样本,并已经被成功地应用到各种地质过程的研究中.从基本概念出发,讨论了流体包裹体的种类和原生、次生流体包裹体的区分,对流体包裹体的岩相学观察要点以及流体包裹体研究的最新进展做了简要的综述,着重介绍了研究中常用的分析方法及变质岩中流体包裹体的研究,并举例说明了流体包裹体在矿床学、石油地质学中的应用,以及近期的一些关于流体包裹体中保存生物标志和生物遗迹化石的研究,最后对未来流体包裹体研究的发展方向作了简单的展望. 相似文献
1000.