Caractérisation minéralogique et microtexturale du vieillissement anthropique du minerai de fer lorrainMineralogical and microtextural characterisation of the anthropic-origin ageing of iron ore in Lorraine (France)     

Guy Dagallier  Dragan Grgic  Françoise Homand 《Comptes Rendus Geoscience》2002,334(7):455-462

The abandoned pillars in iron mines in Lorraine show that the oolitic ore underwent several chemical-mineralogical transformations. The first one is a rapid alteration of the diagenetic siderite and berthierine cement promoted by a bacterial flora. The oolites of goethite pack down and get loaded by deviatory-type stresses; they desquamate, get deformed and become powdery; the ore looses its cohesion. A second step, featuring recrystallisation–neoformation of berthierine in the previously formed micro-cavities, then the formation of a cavernous goethite–hematite crust, leads to a low cohesion to the crumbled ore; this anthropic-origin ageing may be one cause of mine collapsing. To cite this article: G. Dagallier et al., C. R. Geoscience 334 (2002) 455–462.  相似文献   

L'ı̂le de la Dominique, à l'origine des avalanches de débris les plus volumineuses de l'arc des Petites AntillesThe Island of Dominica,site for the generation of the most voluminous debris avalanches in the Lesser Antilles Arc     

Anne Le Friant  Georges Boudon  Jean-Christophe Komorowski  Christine Deplus 《Comptes Rendus Geoscience》2002,334(4):235-243

Results from recent fieldwork and the Aguadomar marine survey in the Lesser Antilles clearly indicate that the volcanic field of southern Dominica has experienced three major edifice collapse events. This led to formation of the most voluminous debris avalanches known in the Caribbean Arc. Submarine hummocky morphology with plurikilometric megablocks is characteristic of debris avalanche deposits. We propose that steep slopes on the western Caribbean side of the island and intense hydrothermal alteration lead to recurrent large-scale edifice collapses. Therefore islands in the Lesser Antilles face a non-negligible risk from generation of tsunamis associated with potential future edifice collapse. To cite this article: A. Le Friant et al., C. R. Geoscience 334 (2002) 235–243.  相似文献   

基于Oracle 10g MapViewer的WebGIS开发     

于荣萍  韦波 《地理空间信息》2008,6(2):12-15

叙述了Oracle 10g MapViewer定义地图数据源的两种方式,给出了创建地图的流程和三种地图请求方式的实现方法,提供了地图操作选项的实现方法。实践表明,使用Oracle 10g MapViewer可实现基于Oracle的WebGIS的快速开发。  相似文献   

共轭伸展褶劈理夹角的定量解析   总被引：16，自引：0，他引：16  

何科昭  赵崇贺  乐昌硕  周正国  聂泽同  邰道乾  叶枬 《地学前缘》1999,6(4):0-0

９０ 年代初以来,中国地质学者先后在浙、皖、赣、湘的“板溪群”及震旦系中发现了古生代的生物化石。因此,再次将“板溪群”是否是前震旦纪的一个变质地层单位、江南古陆是否存在以及华南大地构造格局是否需要重新厘定等问题提了出来。１９９３ 年笔者于赣东北蛇绿混杂岩带内的“双桥山群”岩块中,首次发现了含晚古生代的放射虫硅质岩。１９９６ 年又在该混杂岩带多处的“双桥山群”岩块和“下震旦统志棠组”中找到了含晚古生代的放射虫硅质岩,还首次在“登山群拔竹坑组”中发现了早古生代的几丁虫化石。经数年野外多次观察和对室内化石鉴定、岩石地球化学测试结果以及岩石学特征的综合分析表明,所发现的含晚古生代放射虫硅质岩及其岩石组合是一套洋盆深水相沉积;登山群拔竹坑组,是早古生代的一套浅水陆棚 深水陆棚 半深海相沉积。结合同行学者在邻区“板溪群”研究方面取得的新成果,笔者认为：“板溪群”不是前震旦纪的一个变质地层单位,而是一个复杂的构造岩带,江南古陆是不存在的,华南从早古生代到中生代早期还经历了一次洋盆演化过程,现在的构造格局是印支运动奠定的  相似文献   

Finite-difference Euler Deconvolution Algorithm Applied to the Interpretation of Magnetic Data from Northern Bulgaria     

Daniela?GerovskaEmail author  Petar?Stavrev  Marcos J.?Araúzo-Bravo 《Pure and Applied Geophysics》2005,162(3):591-608

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PRELIMINARY STUDY ON THE OPHIOLITIC MELANGE IN THE YALU TSANGPU GRAND CANYON AREA   总被引：1，自引：0，他引：1  

Geng Quanru  Pan Guitang  Liu Yuping  Zheng Lailing  Liu Chaoji WT  ”BX 《地学前缘》2000,(Z1)

PRELIMINARY STUDY ON THE OPHIOLITIC MELANGE IN THE YALU TSANGPU GRAND CANYON AREA  相似文献   

Usable Values of Nickel Ore and Nickel Concentrate Certified Reference Materials          下载免费PDF全文

Zhizhong Cheng  Mei Liu  Hongku Huang  Tiexin Gu  Weidong Yan  Hongli Wen 《Geostandards and Geoanalytical Research》2015,39(2):221-232

The preparation and characterisation of three nickel ores and two nickel concentrate certified reference materials are described in this paper. The samples of nickel ore and nickel concentrate were collected from the Hongqiling nickel deposit in Jilin province. The raw materials were crushed and passed through a 2.0‐mm sieve. The rough samples were then ground for 48 hr in a high‐alumina ball mill to a final size of < 0.074 mm. Homogeneity of the samples was tested by X‐ray fluorescence spectrometry (WD‐XRF) and inductively coupled plasma‐atomic emission spectrometry (ICP‐AES). The relative standard deviations (RSD) of results on mass fraction measurements by WD‐XRF were < 1.0% m/m for eighteen components. F‐tests showed that all five samples were homogeneous. Nineteen laboratories contributed with measurement results (2127 in total) for the certification of mass fractions for twenty‐three elements and compounds. Twenty‐three components in the nickel ores and twenty components in the nickel concentrates were characterised as certified values, while the Ni mass fractions ranges from 0.1 to 9.02% m/m in these certified reference materials. These five samples were approved as national certified reference materials by the National Organisation of Reference Materials of China in 2012.  相似文献   

Determination of Boron Concentration in Geochemical Reference Materials Extracted by Pyrohydrolysis and Measured by ICP‐MS          下载免费PDF全文

Agnès Michel  Johanna Noireaux  Mickaël Tharaud 《Geostandards and Geoanalytical Research》2015,39(4):489-495

This article presents new boron concentrations for nine geochemical reference materials (GS‐N, FK‐N, GL‐O, BX‐N, DT‐N, AN‐G, GH, Mica‐Fe, Mica‐Mg). After extraction by a modified pyrohydrolysis technique, boron concentrations were measured by ICP‐MS. The blank levels for the whole procedure were 0.091 ± 0.020 ng ml^?1 or 14 ± 5 ng of boron in total. The method was first validated by measuring nine reference materials with known boron concentrations. The determined boron concentrations are all within the range of recommended or published values, which means that the yields were 100%, and show precisions below 10% for samples containing over 2 μg g^?1 of boron.  相似文献   

新疆哈密市红海铜金矿地质特征及成矿预测   总被引：2，自引：0，他引：2  

甘先平  方同辉  王宁  张锐 《矿产与地质》2015,(1)

红海铜金矿位于卡拉塔格铜金成矿带,是最近发现的VMS矿床,本文主要介绍了该矿的区域地质、矿区地质、构造及矿脉特征。通过对成矿地质特征进行分析研究,认为该区具有良好的成矿条件和找矿前景。  相似文献   

Platinum‐Group Element Results for Two Cobalt‐Rich Seamount Crust Ultra‐Fine Reference Materials: MCPt‐1and MCPt‐2     

Yimin Wang  Xiaohong Wang  Wenjun Qu  Yushu Gao  Tiexin Gu  Xingtao Fan  S.I. Andreev  Xuefa Shi 《Geostandards and Geoanalytical Research》2011,35(3):341-352

Two Co‐rich seamount crust reference materials, MCPt‐1 and MCPt‐2, were prepared using ultra‐fine particle size milling technique and characterised for the platinum‐group elements (PGEs). The raw material for these two reference materials was collected separately from the Magellan seamounts of the western Pacific Ocean and the seamounts of the central Pacific Ocean by Russian and Chinese scientists. First, they were ground by ball mill to a ?200 mesh powder, then further processed by ultra‐fine jet mill and well‐mixed. The particle size distributions of the samples were tested by a laser particle analyser; the average particle size was 1.8 and 1.5 μm (equal to about 2000 mesh) respectively. The homogeneity of six major and minor elements in these two materials was tested at the milligram level of sampling mass by high‐precision wavelength dispersive X‐ray fluorescence (XRF) spectrometry and at the microgram level of sampling mass by electron probe microanalyser. The homogeneity of more than forty trace elements, including Pt, was tested at the microgram level of sampling mass by LA‐ICP‐MS. Except for Rh, all PGEs were determined by isotope dilution‐ICP‐MS. Platinum in MCPt‐1 and MCPt‐2 was characterised as certified values, whereas the other five PGEs in MCPt‐1 and MCPt‐2 were reported as reference values. In addition, the information values of sixty‐two major, minor and trace elements were obtained by XRF, ICP‐AES and ICP‐MS. The minimum sampling mass for the determination of PGEs was 1 g, while the minimum sampling mass for the determination of the other elements was 2–5 mg.  相似文献