排序方式： 共有20条查询结果，搜索用时 125 毫秒
11.
江苏某地红土型金矿地质特征及成矿机理分析 总被引：3，自引：0，他引：3
江苏某处金矿为渗流热卤水—次生富集沉积成因,工业类型属改造红土型金矿床,矿石类型主要为含泥化角砾红土金矿石,成矿物质最终源于含金碳盐岩地层,受构造、地下（热）水及气候等因素控制。 相似文献
12.
R. Braucher D. L. Bourls E. T. Brown F. Colin J. -P. Muller J. -J. Braun M. Delaune A. Edou Minko C. Lescouet G. M. Raisbeck F. Yiou 《Chemical Geology》2000,170(1-4):95-111
Depth profiles of in situ-produced cosmogenic nuclides, including 10Be (T1/2=1.5×106 years) and 26Al (T1/20.73×106 years), in the upper few meters of the Earth's crust may be used to study surficial processes, quantifying denudation and burial rates and elucidating mechanisms involved in landform evolution and soil formations. In this paper, we discuss the fundamentals of the method and apply it to two lateritic sequences located in African tropical forests. 相似文献
13.
A Paleoproterozoic lateritic paleosol overlain by ultra-mature/mature quartzite is reported for the first time from three localities in the Svecofennian province in southern Finland. These are important indicators for warm paleoclimate and continental paleoenvironment. Ultra-mature quartzites above the lateritic paleosols are overlain by matrix-supported conglomerates followed by mature quartzites. These latter rocks are related to incipient rifting followed by main rift stage starting with increasingly more immature meta-arkose. 相似文献
14.
Bauxite deposits of Jharkhand in India are resulted from the lateritization process and therefore are often associated with the laterites. In the present study, ASTER (Advanced Space borne Thermal Emission and Reflection Radiometer) image is processed to delineate bauxite rich pockets within the laterites. In this regard, spectral signatures of lateritic bauxite samples are analyzed in the laboratory with reference to the spectral features of gibbsite (main mineral constituent of bauxite) and goethite (main mineral constituent of laterite) in VNIR–SWIR (visible-near infrared and short wave infrared) electromagnetic domain. The analysis of spectral signatures of lateritic bauxite samples helps in understanding the differences in the spectral features of bauxites and laterites. Based on these differences; ASTER data based relative band depth and simple ratio images are derived for spatial mapping of the bauxites developed within the lateritic province. In order to integrate the complementary information of different index image, an index based principal component (IPC) image is derived to incorporate the correlative information of these indices to delineate bauxite rich pockets. The occurrences of bauxite rich pockets derived from density sliced IPC image are further delimited by the topographic controls as it has been observed that the major bauxite occurrences of the area are controlled by slope and altitude. In addition to above, IPC image is draped over the digital elevation model (DEM) to illustrate how bauxite rich pockets are distributed with reference to the topographic variability of the terrain. Bauxite rich pockets delineated in the IPC image are also validated based on the known mine occurrences and existing geological map of the bauxite. It is also conceptually validated based on the spectral similarity of the bauxite pixels delineated in the IPC image with the ASTER convolved laboratory spectra of bauxite samples. 相似文献
15.
The role of laterites and clay in the adsorption of trace elements and consequent remediation of contaminated water from toxic elements has been studied. Laterite, clay and associated water samples from industrially and biologically polluted rivers and wells from Eloor-Kalamassery are analysed for Cr, Mn, Co, Ni, Cu, Zn, Cd, Pb, Bi, As, and Hg contents. The cation exchange capacity of the clay-organic matter components from the in situ and transported laterites and clay in differing environments of pollution are responsible for the reduction and depletion of toxic elements concentrated in the polluted water medium. Adsorption of toxic elements by laterite has further been corroborated by a simulation experiment conducted in the laboratory. An artificial laterite bed was prepared and water containing known amounts of Cr, Zn, Ni and Mn were allowed to flow overnight through the bed at uniform rate. Analysis of artificial laterite bed shows enrichment of Cr, Zn, Ni, Mn, indicating the absorbent properties of laterite. 相似文献
16.
This work aims to elucidate the factors governing the mobility of metals in soils of a lateritic nickel ore deposit in New Caledonia. The transfer of nickel and associated metals is determined along a topographic sequence ranging from a plateau to a thalweg. Mining exploration borehole data and soil pit data enabled us to define the general geochemical trends of the lateritic weathering. The homogeneous topsoil, which consists mainly of iron oxy-hydroxides, exhibits various amounts of plant available metals. Two interrelated factors control the differences in metal availability: (1) the presence of nickel-rich soil horizons underlying the topsoil and formed of silicate minerals, and (2) the biological cycling of metals from these horizons to the surface. These results have major implications for topsoil management during the mining activity where it is important to minimise metal inputs to water systems and to restore endemic vegetation after mining. 相似文献
17.
:本文概述了老厂红土型银锰矿床成矿地质背景、地质特征及成矿规律,提出本矿床总体属初生红土型银锰矿床,成矿作用主要与红土化作用有关,银锰成矿物质主要来源于C2+3—P1碳酸盐岩,并将银锰次生富集过程划分为四个阶段。 相似文献
18.
Lateritic bauxites in the coastal lowlands of Suriname form part of a belt along the northern margin of the Guiana Shield that has long been one of the world's major bauxite producing regions. The Surinamese deposits, many of which with an extensive mining history, originated on Tertiary siliciclastic sediments and were mostly buried under a layer of young sediments. The bauxite-bearing sequences are generally topped with an iron-rich layer largely made up of hematite and goethite. It covers a gibbsite-rich bauxite horizon that passes downward into a kaolinitic bottom section containing anatase and zircon as main accessory minerals. Weathering profiles across formerly mined deposits were analyzed for geochemical and mineralogical properties aimed at exploring compositional diversity, underlying controls of bauxite-formation and the nature of precursor sediments.Studied profiles in different parts of the coastal plain reveal overall similarities between individual deposits in showing significant depletion of Si, K, Na, Mg and Ca and strong, primarily residual, relative enrichment of Al, Ti, Zr, Nb, Hf, Ta and Th. In detail, however, there are distinct differences in major and trace-element signatures, accessory mineral assemblages, facies distribution and provenance of the terrigenous precursor sediments. Enrichments in high field-strength elements and heavy rare earth elements are largely attributable to accumulation of heavy minerals like zircon in the precursor. Petrological and trace-element evidence does not support a direct genetic relationship between bauxite and the underlying saprolitic clays. The complex petrologic characteristics and compositional heterogeneity of the coastal-plain deposits can essentially be explained by element fractionation, primarily through selective leaching, in combination with relative and absolute enrichment processes, erosion and reworking during two-stage, polycyclic bauxitization of a heterogeneous precursor. 相似文献
19.
高海拔山地碳酸盐岩风化壳的发育特征及其地貌意义 总被引：9，自引：1，他引：8
研究区位于云南东川拱王山山顶的落雪,海拔高度在3600m左右。山顶面为一缓丘及丘间溶蚀洼地构成的第三纪残留夷平面。在夷平面上发育了碳酸盐岩的黄色风化壳。本文基于风化壳的地球化学、物理化学及矿物学等特征,重点研究了风化环境对风化壳发育特征的影响,以及风化壳与第三纪残留夷平面的关系。所研究的风化壳剖面发育于低温、降水充沛和湿润的气候条件下。分析测试结果表明,风化壳仍处于CaO、MgO淋失, SiO2富积阶段,是一种弱度风化的富SiO2风化壳。风化壳的特征表明其形成于第三纪夷平面解体之后,而不能代表第三纪夷平面的原有相关堆积。 相似文献
20.
