黔东南变质碎屑岩型金矿找矿前景分析   总被引：2，自引：0，他引：2  

马晓旻  邵文阔  张凯 《矿物学报》2007,27(3):489-492

黔东南天柱-锦屏-黎平金成矿区，位于中国江南古陆变质碎屑岩型金矿成矿带的西端，采金历史悠久，但勘查研究程度不高，小型矿床点星罗棋布却未发现大型矿床。研究认为，黔东南金矿工业类型与韧性剪切带有关，主要为石英脉型和构造蚀变岩型，可能存在产状平缓的蚀变糜棱岩型；从成矿条件、成矿规律、成矿特征等方面分析，黔东南金矿勘查很有前景。  相似文献   

河南商城鲢鱼尖变形花岗岩体地质、地球化学及含矿性特征     

张保平  丁见广  申开洪 《世界地质》2007,26(4):413-419

河南商城鲢鱼尖变形花岗岩岩体的地质、地球化学特征、成因及含矿性研究表明，岩体具有贫SiO2、K2O，富Al2O3、TiO2、CaO、MgO、Fe2O3＋FeO之特征，Na2O＋K2O为7．65％～8．84％。K2O／Na2O为0．66～0．9；分异指数（Dr）为71．2～80．7，ASI值为0．81～0．98，氧化指数（OX）为0．55～0．32，8值为3．1～4．05，为准铝质钙碱性岩石系列。在An—Ab—Or图解及R1-R2多阳离子图解上多落于花岗闪长岩一二长花岗岩区，为斑状二长花岗岩-斑状花岗闪长岩。岩体与围岩接触带上可形成Cu、Pb、Zn、Ag、Mo多金属矿（床）。  相似文献   

C02-CH4流体与金成矿作用：以阿尔泰山南缘和穆龙套金矿为例     

徐九华谢玉玲  丁汝福阴元军单立华  张国瑞 《岩石学报》2007,23(8):2026-2032

造山型金矿的成矿作用与H20-CO2流体有着密切的联系。然而对阿尔泰山南缘和穆龙套金矿的流体包裹体研究表明，无水的CO2-CH4流体在中亚成矿域中一些金矿床中具有同样重要意义。阿尔泰山南缘萨热阔布金矿包裹体的Xch4达0.20～0.23，穆龙套金矿的XCH4为0.07～0.23。CH4扩大了流体不混溶的范围，有利于对Au的富集沉淀。CO2流体在Au成矿中的重要作用至少包括了三方面的意义，即：缓冲流体PH值范围、提高流体中的Au含量并使其维持与还原硫的络合作用进行迁移；扩大超临界流体的温度范围；增加流体不混溶的区域。CH4的加入扩大了流体不混溶的范围，有利于对Au的富集沉淀。  相似文献   

Gold ore-forming fluids of the Tanami region, Northern Australia   总被引：1，自引：0，他引：1  

Terrence P. Mernagh  Andrew S. Wygralak 《Mineralium Deposita》2007,42(1-2):145-173

Fluid inclusion studies have been carried out on major gold deposits and prospects in the Tanami region to determine the compositions of the associated fluids and the processes responsible for gold mineralization. Pre-ore, milky quartz veins contain only two-phase aqueous inclusions with salinities ≤19 wt% NaCl eq. and homogenization temperatures that range from 110 to 410°C. In contrast, the ore-bearing veins typically contain low to moderate salinity (<14 wt% NaCl eq.), H₂O + CO₂ ± CH₄ ± N₂-bearing fluids. The CO₂-bearing inclusions coexist with two-phase aqueous inclusions that exhibit a wider range of salinities (≤21 wt% NaCl eq.). Post-ore quartz and carbonate veins contain mainly two-phase aqueous inclusions, with a last generation of aqueous inclusions being very CaCl₂-rich. Salinities range from 7 to 33 wt% NaCl eq. and homogenization temperatures vary from 62 to 312°C. Gold deposits in the Tanami region are hosted by carbonaceous or iron-rich sedimentary rocks and/or mafic rocks. They formed over a range of depths at temperatures from 200 to 430°C. The Groundrush deposit formed at the greatest temperatures and depths (260–430°C and ≤11 km), whereas deposits in the Tanami goldfield formed at the lowest temperatures (≥200°C) and at the shallowest depths (1.5–5.6 km). There is also evidence in the Tanami goldfield for late-stage isothermal mixing with higher salinity (≤21 wt% NaCl eq.) fluids at temperatures between 100 and 200°C. Other deposits (e.g., The Granites, Callie, and Coyote) formed at intermediate depths and at temperatures ranging from 240 to 360°C. All ore fluids contained CO₂ ± N₂ ± CH₄, with the more deeply formed deposits being enriched in CH₄ and higher level deposits being enriched in CO₂. Fluids from deposits hosted mainly by sedimentary rocks generally contained appreciable quantities of N₂. The one exception is the Tanami goldfield, where the quartz veins were dominated by aqueous inclusions with rare CO₂-bearing inclusions. Calculated δ ¹⁸O values for the ore fluids range from 3.8 to 8.5‰ and the corresponding δD values range from −89 to −37‰. Measured δ ¹³C values from CO₂ extracted from fluid inclusions ranged from −5.1 to −8.4‰. These data indicate a magmatic or mixed magmatic/metamorphic source for the ore fluids in the Tanami region. Interpretation of the fluid inclusion, alteration, and structural data suggests that mineralization may have occurred via a number of processes. Gold occurs in veins associated with brittle fracturing and other dilational structures, but in the larger deposits, there is also an association with iron-rich rocks or carbonaceous sediments, suggesting that both structural and chemical controls are important. The major mineralization process appears to be boiling/effervescence of a gas-rich fluid, which leads to partitioning of H₂S into the vapor phase resulting in gold precipitation. However, some deposits also show evidence of desulfidation by fluid–rock interaction and/or reduction of the ore-fluid by fluid mixing. These latter processes are generally more prevalent in the higher crustal-level deposits.  相似文献   

大井铜-锡多金属矿床地质特征及其成因     

张信 《矿产与地质》2007,21(4):415-420

通过对大井铜-锡多金属矿床成矿地质环境、矿床地质特征以及对岩（矿）石同位素、稀土元素、成矿温度等地球化学和成矿物理化学环境的研究,认为,大井铜-锡多金属矿床为一典型的岩浆热液充填型矿床。与成矿有关的隐伏岩体受深部隐伏的深大断裂控制,可能与黄岗梁矽卡型铁-锡矿床同属一构造岩浆成矿带上不同成矿环境下形成的矿床。并认为,在该成矿带上及大井矿区深部仍有较大的找矿潜力。  相似文献   

青海省斑岩铜矿地质特征及找矿方向探讨     

张梅芬  刘建华  肖文进  杨自安 《矿产与地质》2007,21(4):440-444

以纳日贡玛斑岩型钼铜矿床为例,对青海省斑岩铜矿产出的地质构造环境、地质特征、成矿地质条件、含矿建造等条件进行了综合分析。在此基础上,对本省斑岩铜矿的找矿方向进行了初步探讨,提出了斑岩型铜矿床的区域构造-岩浆岩带、区域地球物理、地球化学、围岩蚀变等找矿标志,划分出有远景的五大斑岩型铜矿成矿带。  相似文献   

黑龙江金厂金矿床地质特征及找矿前景分析     

李体刚  王艳忠  郎利国 《物探与化探》2007,31(Z1):94-97

金厂金矿床位于太平岭隆起与老黑山坳陷的隆坳交接部位。矿化有4种类型:隐爆角砾岩型、环状放射状断裂充填型、岩浆穹窿型、接触带型。矿区内已初步建立隐爆角砾岩型—环状放射状断裂充填型—岩浆穹窿型—接触带型的矿床成因模型及找矿模型。综合研究矿区内的成矿规律及物探、化探、遥感异常特征,矿区及外围有较大的找矿远景。  相似文献   

甘肃天水柴家庄金矿地质特征与找矿标志     

杨根生 《西北地质》2007,40(4):36-42

柴家庄金矿位于西秦岭造山带北秦岭加里东褶皱带柴家庄-庞家河金矿带上,赋存于柴家庄二长花岗岩外接触带的丹凤群中,严格受NE向及NNW向断裂控制。矿床的形成受丹凤群、印支-燕山期酸性侵入体及断裂构造3种因素控制。岩体外接触带0～2km范围内的NE向、NNW向断裂构造带是找矿的最佳方向。在详细研究矿床地质及地球化学特征的基础上,总结了该矿床的主要控矿因素,并归纳了主要找矿标志,为区内找矿提供了新思路。  相似文献   

Reappraisal of the structure of the Western Iron Ore Group, Singhbhum craton, eastern India: Implications for the exploration of BIF-hosted iron ore deposits   总被引：1，自引：0，他引：1  

Gautam Ghosh  Joydip Mukhopadhyay 《Gondwana Research》2007,12(4):525-532

The middle to late Archean Iron Ore Group rocks occurring along the western margin (the Western Iron Ore basin) of the Singhbhum Granite massif in the Singhbhum craton were deformed during Iron Ore orogeny and are disposed in a horseshoe-shaped synclinal structure in the eastern part of the Indian shield. The Western Iron Ore basin hosts almost all the major high-grade iron ore deposits of eastern India. Contrary to the established view, present analysis emphasizes that the horseshoe fold in reality is a synclinorium consisting of a syncline–anticline fold pair which were later cross-folded along an east–west axis.

Structural analysis in the eastern anticline of the ‘horseshoe synclinorium’ suggests that the BIF hosting the high-grade iron ore bodies are disposed in three linear NNE–SSW trending belts, each showing an open synclinal geometry. Later cross folding produced development of widespread dome and basin pattern at the sub-horizontal hinge zones of these synclinal fold belts. The major iron ore deposits in the eastern anticline at the present level of erosion are preferentially localized within shallow elongated basinal structures only. The axis of the adjoining western syncline was similarly uplifted as partial culminations where cross-folded against E–W anticlinal axes. But here, the BIF-iron ore bodies are preferentially localized within elongated domal structures in contrast to the basinal sites in the adjacent eastern anticline. Such an inference based on structural analysis could probably be utilized as a potential tool for all future explorations, reserve estimation and recovery of the iron ore deposits in the terrain.  相似文献   

柴北缘—东昆仑地区造山型金矿床的流体包裹体研究   总被引：5，自引：0，他引：5       下载免费PDF全文

张德全 张 慧丰成友  佘宏全李进文 李大新 《中国地质》2007,34(5):843-854

柴达木盆地北缘(以下简称柴北缘)—东昆仑地区已经勘查发现了一批造山型金矿,它们是加里东和晚华力西—印支复合造山作用的产物。通过柴北缘—东昆仑地区12处造山型金矿中流体包裹体研究发现,该区造山型金矿中发育两种不同的成矿流体:低盐度的H2O-CO2-NaCl-CH4流体和低盐度的H2O-CO2-NaCl±CH4。前者的XCH4、XCO2和XH2O分别为0.14～0.34(平均值0.24)、0.11～0.59(平均值0.34)和0.64～0.31(平均值0.42),温度变化为180～270℃,压力为180～560Mpa,是晚加里东期碰撞造山作用的产物,主要沿加里东碰撞造山带边界的上地壳底部-中地壳上部的塑性变形带大规模流动,并在本区形成了广泛的金矿化;后者的XCH4、XCO2和XH2O分别为0～0.12(平均值0.06)、0.18～0.25(平均值0.21)和0.79～0.69(平均值0.73),温度变化为280～449℃(主要在280～360℃),压力为80～230Mpa,主要与晚华力西—印支期碰撞造山作用有关,其中不少矿床还受侵入岩浆作用的影响,其沿晚华力西—印支期碰撞造山带边界的上地壳大规模流动,导致了本区造山型金矿的最终定位。上述两期成矿流体的盐度相差不大,总体变化在1.4%～11.4%(NaCl)(大部分集中于2.7%～9.1%)。压力-深度换算结果显示,本区晚华力西—印支期碰撞造山作用表现出地壳强烈隆升过程,其最大隆升幅度达12km。这说明该区大规模的造山型金成矿作用发生在地壳隆升的背景之下。  相似文献