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21.
通过对中国东部金成矿区域地质特征的分析,根据氢氧同位素及流体包裹体数据特征,表明中国东部金矿床成矿流体主要来自大气降水,其次为变质作用过程释放的水和岩浆分异水;成矿金属组分主要来自太古宙变质岩系。  相似文献   
22.
广西难处理金矿固化焙烧氰化提金试验   总被引:1,自引:0,他引:1  
通过对广西六梅金矿、明山金矿、金牙金矿含高砷高硫难浸金矿石进行固化焙烧—氰化提金的试验研究 ,获得了砷、硫固定率分别为 99.0 3%、97.0 4 % ,金浸出率 92 .35 %的较好指标 ,为这类难浸金矿的开发 ,展示了一种经济有效的途径  相似文献   
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古侵蚀沉积间断面型金矿是桂西的主要金矿床类型。文章着重分析该类型金矿成矿地质条件 ,论述矿床成因及成矿机理 ,认为此类型金矿易采易冶 ,经济效益显著 ,建议加大开发力度。  相似文献   
25.
黄金的成色     
刘儒 《吉林地质》1994,13(3):81-83,45
黄金的成色并不是一成不变的,它成色的高低是与成矿温度、成矿阶段、深度、时代、变质程度、水溶液及风化作用等有一定关系,我们从这些关系中可以寻找到我们找矿的捷径和依据。  相似文献   
26.
程明高 《铀矿地质》1991,7(6):321-327,344
本文较系统地总结了我国北西部金矿主要类型、矿化特征和金矿时空分布规律,在此基础上划分出4个成矿区、12条成矿带、32条成矿亚带,从而指明了找矿方向,为贯彻“以铀为主,综合找矿,多种经营,搞活地质”的方针,提供了较好的参考资料。  相似文献   
27.
MARC J.P. GOUW 《Sedimentology》2008,55(5):1487-1516
Ancient fluvial successions often act as hydrocarbon reservoirs. Sub‐surface data on the alluvial architecture of fluvial successions are often incomplete and modelling is performed to reconstruct the stratigraphy. However, all alluvial architecture models suffer from the scarcity of field data to test and calibrate them. The purposes of this study were to quantify the alluvial architecture of the Holocene Rhine–Meuse delta (the Netherlands) and to determine spatio‐temporal trends in the architecture. Five north–south orientated cross‐sections, perpendicular to the general flow direction, were compiled for the fluvial‐dominated part of the delta. These sections were used to calculate the width/thickness ratios of fluvial sandbodies (SBW/SBT) and the proportions of channel‐belt deposits (CDP), clastic overbank deposits (ODP) and organic material (OP) in the succession. Furthermore, the connectedness ratio (CR) between channel belts was calculated for each cross‐section. Distinct spatial and temporal trends in the alluvial architecture were found. SBW/SBT ratios decrease by a factor of ca 4 in a downstream direction. CDP decreases from ca 0·7 (upstream) to ca 0·3 (downstream). OP increases from less than 0·05 in the upstream part of the delta to more than 0·25 in the downstream delta. ODP is approximately constant (0·4). CR is ca 0·25 upstream, which is approximately two times larger than in the downstream part of the delta. Furthermore, CDP in the downstream Rhine–Meuse delta increases after 3000 cal yr BP. These trends are attributed to variations in available accommodation space, floodplain geometry and channel‐belt size. For instance, channel belts tend to narrow in a downstream direction, which reduces SBW/SBT, CDP and CR. Tectonics cause local deviations in the general architectural trends. In addition, the positive correlation between avulsion frequency and the ratio of local to regional aggradation rate probably influenced alluvial architecture in the Rhine–Meuse delta. The Rhine–Meuse data set can be a great resource when developing more sophisticated models for alluvial architecture simulation, which eventually could lead to better characterizations of hydrocarbon reservoirs. To aid such usage of the Rhine–Meuse data set, constraints for relevant parameters are provided at the end of the paper.  相似文献   
28.
Granular carbonate deposits of Late Pleistocene to Early Holocene age, commonly referred to as ‘miliolite limestone’, occur in a linear belt, parallel to the southern coast of Saurashtra, India. In the present study area these carbonate deposits are found in select valleys between ridges and mounds of pyroclastic material present in the Deccan trap plateau. Two different depositional histories have been proposed for these sediments. The presence of marine bioclasts led to the postulation of a marine origin for these deposits. The second school of thought propounded redeposition of the coastal sediments by aeolian processes. Although a few features could not be explained by the proposed aeolian model, critical comparison of these two views favoured the aeolian origin. The mode of occurrence, lithological and structural attributes, and microscopic evidence presented here, also support a possible aeolian origin for these deposits. Experimental observation indicates that these carbonate aeolianites represent backflow deposits, which accumulated because of the flow separation caused by the presence of topographic highs. The conspicuous concave‐up geometry of the deposit conformed to the shape of the separation bulb. In view of the inferred depositional mechanism, the disposition of the deposits and the signature of the palaeoflow direction suggest that the carbonate particles were derived from the north‐western coast of Saurashtra by strong south‐easterly winds. Massive granular carbonates with outsized basement clasts appear to be the product of avalanching of granular material from the higher contours because of oversteepening of the primary deposit.  相似文献   
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30.
H.M. Rajesh   《Ore Geology Reviews》2008,33(3-4):382-396
The Rockhole area, Northern Territory, Australia, hosts a number of Proterozoic unconformity-related uranium deposits. The geology of the area features within Paleoproterozoic rocks of the Pine Creek Orogen, near the unconformity with overlying platform cover sandstone of the Paleo- to Mesoproterozoic McArthur Basin. Landsat Enhanced Thematic Mapper plus (ETM+) data was used in the Rockhole area to assist in mapping geological structures and lithology, and to identify anomalous concentrations of ferrous minerals, the product of alteration, which can be indicators of buried uranium mineralization. Several image-processing procedures were applied to the ETM+ data to identify, isolate and enhance mineralogical information as simple and complex false color composites. ETM+ 754 shown as red green and blue respectively was the best simple image. Overall, complex images based on Principal Component Analysis proved to be the most useful products. Sandstone, shale and siltstone, the target lithologies, Koolpin Formation, the target stratigraphic unit, and bleaching pattern due to the removal of iron(II) compounds, the target alteration pattern, were confidently mapped to provide information required by the mineral emplacement model, which ultimately identified areas of likely uranium mineralization. Thus the contrasting behavior of the two principle oxidation states of uranium and iron can be utilized to map/delineate bleached alteration zones associated with economic concentrations of uranium using multispectral sensors like Landsat or better hyperspectral sensors.  相似文献   
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