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941.
中国接触交代型铜矿床品位、吨位模型   总被引:4,自引:1,他引:3  
依据“全国矿产储量数据库”的资料,对全国277个接触交代型铜矿床建立了品位模型、吨位模型以及品位一号位联合模型。模型类型包括频率直方图、累积频率分布图以有用双对数坐标表示的理论分布模型,分别总结了该类型铜矿 品位及吨位分布的典型数学特征。  相似文献   
942.
This contribution is a short history of the Zambian copper flower, Becium homblei (recently renamed B. centraliafricanum that has attracted attention as a plant associated with Cu-rich soils. It has a peculiar discontinuous distribution in Central Africa which has been explained in terms of biotype depletion. A field investigation into the ecology of the species shows that it is able to tolerate soil Cu concentrations of up to 15,000 μg/g (ppm), and soil nickel concentrations of nearly 5000 μg/g. B. homblei is also found on areas where soil metals are in trace quantities, and where soil bases, particularly Ca, are low. In spite of its tolerance to a wide range of edaphic conditions, the distribution of the species is very restricted in Zimbabwe, and this is almost certainly due to severe interspecific competition with a closely related species, B. obovatum, which is common on soils not unusually enriched in heavy metals. Pioneering work on geobotanical prospecting by use of Becium homblei was carried out by the late G. Woodward and others in the 1950s and 1960s. This species was used successfully for geobotanical prospecting for Cu. This present report is a brief history of these pioneering studies  相似文献   
943.
白银厂矿田折腰山海相火山岩型铜矿床地球化学异常特征   总被引:5,自引:1,他引:4  
刘崇民 《地质与勘探》1999,35(5):28-30,35
论述了白银厂矿田折腰山铜矿床的地质,地球化学特征,认为该矿床的主要指示元素是Cu,Ag,As,Sb,Hg,Pb,Zn,Au,Cd,Ba,进而讨论了这些元素在区域,矿床的异常特征以及垂直分带规律,最后总结出矿床的地球化学异常模式。  相似文献   
944.
Abstract: The Bidjovagge gold-copper deposit, northern Norway occurs in the lower Proterozoic Kautokeino greenstone belt, and consists of ten ore bodies in albite felsite, graphite schist and meta-diabase sills, along with a series of syenodiorite dykes. Calcite is one of the most important gangue minerals occurring within the ore veins. The early primary calcite samples from A, C and D ore bodies (copper–rich) show almost flat chondrite-normalised REE curves, and slightly positive Eu anomalies. A Sm-Nd isotope age of 1858 ± 72 Ma (2ρ) has been given based on fifteen primary calcite samples. The Sm-Nd age of calcite is in well agreement with previously published U-Pb davidite age of 1885 ±18 Ma (2ρ) and Sm-Nd davidite age of 1886 ± 88 Ma (2ρ). All these isotopic age data indicate that the gold-copper mineralisation may occur during or slightly after the peak of the Svecokarelian orogeny. Two late primary calcite samples from C and D ore bodies have flat chondrite-normalised LREE curves, positive HREE curves, and negative Eu anomalies. In contrast, most of the early primary calcite samples from B ore body (gold–rich) show an overall negative chondrite-normalised REE slope and negative Eu anomalies. Sm-Nd data on seven primary calcite samples from the B ore body are relatively scattered, and gave an isochrone age of 1809 ± 150 Ma (2ρ), identical to the age of the calcite samples from A, C and D ore bodies. Two late primary calcite samples from the B ore body have almost flat chondrite-normalised REE slope and negative Eu anomalies. REE patterns and eNd (T) values of calcites suggest that the ore fluids for the calcites from the A, C and D ore bodies derived their metals from mafic igneous rocks (diabase sills). For the secondary calcites from the C ore body, their relative high initial Nd (T) values at 1858 Ma imply that much more radiogenic Nd-component were incorporated during calcite crystallisation when another ore fluid emplaced. Combined Nd isotope data and REE geochemical features suggest that the isotopically more evolved source such as albite felsite and syn-genetic high level syenodiorite dykes were probably metal source for these calcites in the B ore body. Three samples of secondary calcite from the B ore body, which obviously deviated from 1809 Ma isochron are easily explained as products of post-ore hydrothermal events.  相似文献   
945.
Abstract: Polymetallic mineralization at the Nakakoshi deposits, Kamikawa town, central Hokkaido, occur as fracture-filling veins in Cretaceous slate of the Hidaka Supergroup. Ten veins have been recognized in NE-SW and E-W directions. Sericite in altered slate which is the host of the deposits, was dated at 31. 1 Ma, Oligocene in age.
No. 9 vein consists of massive chalcopyrite ore with various kinds of minerals such as pyrite, pyrrhotite, arsenopyrite, sphalerite, tetrahedrite, Ag-minerals and Cu–Zn–Fe–In–Sn–S minerals, quartz and sericite. Chalcopyrite and pyrite contain sphalerite star and sphalerite with chalcopyrite emulsions. Maximum indium contents of sphalerite and the Cu–Zn–Fe–In–Sn–S minerals are 1. 8 and 16. 3 wt%, respectively. The sulfur isotopic ratios, δ34S of ore minerals, range from –12. 9 to –9. 6%. Formation temperatures of the sulfide minerals are estimated as 300–500°C, based on the paragenesis and chemical compositions of the minerals.  相似文献   
946.
西藏冈底斯三处斑岩铜矿床流体包裹体及成矿作用研究   总被引:22,自引:6,他引:16  
对西藏冈底斯斑岩铜矿带中的驱龙、冲江斑岩铜矿床和与斑岩有关的帮浦铜多金属矿床进行了流体包裹体岩相学、显微测温和激光拉曼探针分析。对斑岩中斑晶石英、硅化脉石英和热液矿物硬石膏内流体包裹体的观测表明,与成矿有关的流体包裹体可以分为气相包裹体、液相包裹体、含子晶的多相包裹体等3类。它们的均一温度变化较大(191~550℃),气相包裹体与含子晶多相包裹体的均一温度相近,主要集中于300~550℃之间。流体的盐度ω(NaCleq)为1.91%~66.75%,含石盐子晶包裹体的盐度ω(NaCleq)范围为32.70%~66.75%。激光拉曼光谱分析表明,子晶以石盐为主,并有较多的黄铜矿;气相包裹体和液相包裹体的气相中含有CO2。低密度的气相包裹体与高密度的液相包裹体、高盐度的含子晶包裹体共生,其均一温度范围一致,但盐度相差较大,指示成矿流体有不混溶作用或沸腾作用。成矿流体来自于岩浆的出溶;金属硫化物直接来源于岩浆。斑晶石英内流体包裹体中的不混溶作用与岩浆的初始沸腾有关;硅化脉石英捕获的流体包裹体与岩浆的二次沸腾有关;而硬石膏内流体包裹体的不混溶与两种不同性质流体的混合作用有关。斑晶石英中包裹体内的黄铜矿子晶是岩浆流体高金属含量的表征而不是矿化开始的标志。冈底斯成矿带内斑岩铜矿的成矿始于岩浆期后高温阶段,随后的高-中温热液阶段是流体大量沉淀矿质的重要时期。  相似文献   
947.
东川蓑衣坡硅质岩型铜矿床的地质地球化学特征及成因   总被引:1,自引:0,他引:1  
蓑衣坡硅质岩型铜矿床产于元古宙裂谷带。矿化主岩为块状硅质岩和条纹(带)状硅质岩;块状硅质岩的SiO2含量为85.66%~96.74%。条纹(带)状硅质岩的SiO2含量为74.83%~87.52%;在TiO2~Al2O3和(K2O Na2O)-Al2O3关系图上和(Co Ni)-(As Cu Mo Pb V Zn)关系图上。其成分投影点均落入与海底热水系统有关或热水沉积岩区的硅质岩区;蓑衣坡矿区矿石的稀土元素总量变化大,且显示轻稀土元素富集。叠加的成矿作用引起轻稀土元素含量升高;并具铈负异常、铕异常不明显的特点。矿石内矿物流体包裹体的均一温度为121~257℃,盐度w(NaClep)为6.2%~8.3%,成矿流体属K^ Ca^2 -SO4^2-型和K^ -Mg^2 -SO4^2-型。矿石的δ^34S值为-14.8~ 17.2‰。δ^18O值为4.9‰,矿石中石英的δ^18O值为12.4‰~16.3‰,位于热泉型石英的δ^18O值变化区间(12.2‰~23.6‰)。矿石中黄铁矿内流体包裹体的δD值为-116.2‰。其δ^O H2O值为-5.7‰,接近美国黄石公园酸性热泉的δD值和δ^18O值。含矿硅质岩的^206Pb/^204Pb比值为17.947~18.951,^207Pb/^204Pb比值为15.606~15.711,^208Pb/^204Pb比值为36.466~38.496。根据矿床地质地球化学特征,笔者认为。蓑衣坡硅质岩型铜矿床的成因类型属裂谷处于拉张裂陷阶段发生的喷流沉积作用形成的硅质岩型铜矿床。  相似文献   
948.
A laboratory-based assessment of copper remobilization from Cu-rich mine tailings exposed to anoxic, sulfide rich waters was performed. The results from incubation experiments, conducted over a 20 day period, were compared to thermodynamic modelling calculations of copper speciation in sulfidic waters. The tailings materials were observed to react rapidly with added sulfide, consuming 159 μmol HS g−1 (dry wt) within a 24 h period. The consumption of sulfide was attributed to a two stage process involving the reduction of Fe-hydroxy phases by sulfide followed by reaction with available Fe2+ and Cu2+ resulting in the formation Fe- and Cu-sulfide phases. During incubation experiments, the dissolved copper concentrations in the absence of sulfide were approximately 0.31 μmol l−1, whereas in the presence of sulfide (0.5–5 mM) concentrations were typically 0.24 μmol l−1. The experiments did not indicate enhanced solubility owing to the formation of soluble copper sulfide species. The predictions (based on the most recent thermodynamic data for aqueous Cu-sulfide and Cu-polysulfide species) did not accurately explain the laboratory observations. Model predictions were greatly influenced by the assumptions made about the oxidation state of copper under anoxic conditions and the solid sulfide phase controlling copper solubility. The study emphasizes the limitations of modelling copper speciation in sulfidic waters and the need for laboratory or field verification of predictions.  相似文献   
949.
七宝山金铜矿位于胶莱盆地西南缘的七宝山地区,在金铜矿外围新发现长老庄含矿隐爆角砾岩带一条, 物探解译工作初步查明了该隐爆角砾岩带地质及地球物理特征:位于激电中梯高阻和低阻接触带上,深部呈低阻、中高激化异常。经钻探验证,在深部发现高品位的银铜铅矿体,矿石中粗粒方铅矿、黄铜矿结晶体肉眼可见,呈团块状富集,铜品位0.493%~5.125%,铅品位0.245%~6.606%,银品位55.2~547.1g/t。表明在金铜矿外围及深部仍具有寻找隐爆角砾岩型高品位银铜铅矿体的潜力。  相似文献   
950.
笔者简单介绍了乔夏哈拉铜(铁)金矿床的基本成矿及其微量元素地球化学特征,指出其主矿体具有“垂向分带”及“铜、金向下同步富集”的特点,认为其容矿火山岩与中基性侵入岩脉具有基本相似的微量元素地球化学行为,铜、金矿石同其容矿火山岩相比具有相对贫K、Rb、Th、Ba,相对富W、Ni、Co、As、Sb、Zn及明显偏低的Th/Ta、La/Yb值。研究稀土元素地球化学,发现铜、金矿石具有明显不同于其容矿火山岩的强Eu富集,后期形成的地质体一般具有相对更为偏低的∑REE值。综合分析表明,该铜(铁)金矿床为一与“层状夕卡岩”有关的火山热液型“层控”矿床。  相似文献   
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