冰碛扇型砂金矿床特征及其成矿初探

成生于冰碛扇内，经一定的生物、物理、化学成矿作用，以砂金形态分布而富集成矿的金矿称为冰碛扇型砂金矿床。它具有沿造山带一定标高范围成群、成带分布，沉积物为近源且半胶结，砂金呈面状分布，并以粒金、块金为主，具胶状、浑圆状、包块状构造形态，分布极不均匀等特征。冰碛扇型砂金矿床的成矿作用与河成砂金矿床有本质的区别。它的成矿作用模式是：造山带下地壳富含的活化金通过新构造运动活化的断裂运移地表，经地下流体和地表流体的迁移聚集到冰碛扇这一封闭稳定的生物、物理、化学障环境中，主要经高效聚金微生物有机胶体成矿作用沉淀、再生加大形成砂金，逐步富集成矿床。而红色磨拉石建造中风化离解的Ｆｅ，Ｍｎ物质对沉淀环境ｐＨ值起着一定的调节作用。冰碛扇型砂金矿床在我国西部造山带内广泛分布，具有一定的工业价值，是砂金矿床中一重要类型，应予以重视     

胶东“玲珑-焦家式”金矿资源潜力与找矿

“玲珑焦家式”金矿的成岩成矿,从新太古代至中生代存在着继承性的成因关系,成矿具有长期性、多源性特点,但中生代燕山早期岩浆活动是主导成矿因素。区域化探成果显示胶东金矿直接矿源岩———郭家岭花岗岩金的丰度比原始矿源岩———早前寒武纪变质沉积岩系及侵入岩系金的丰度低1/2。郭家岭花岗岩面积在2 km2以上岩体定量估计金亏损总量与胶东金矿总量预测的资源量相当,从一个侧面展现了胶东金矿资源的潜力。望儿山金矿的找矿实践展示,焦家式金矿在1 000 m以下尚有巨大潜力,整个胶东金矿产区在3 000 m以上的资源潜力应在5000 t以上。     

物探方法在江西省茅排金矿的应用效果

茅排金矿床属中－低温硫化物金矿床，矿体的分布严格受断裂构造控制．通过应用不同的物探方法来寻找控矿断裂，从而达到间接地寻找矿体分布的目的，取得了较好的效果。     

三峡重庆库区深部地球物理特征与断裂构造

为了深入研究三峡重庆库区岩石圈动力学特征及其对断裂构造活动的控制和影响．并为之提供基础资料，为三峡重庆库区地震、地质灾害的监测与防治提供基础依据，在已有地球物理资料的基础上，从综合地球物理研究角度出发，通过实测地震测线资料的再解释．采用新的处理技术方法，对本区的东西向主剖面和南北向支测线的地震测深资料进行二维射线追踪处理、Pg波成像；选用场分离技术、位移数字成像技术重新处理了重力和航磁资料，通过联合反演来建立深部二维构造剖面，对剖面所揭示的基底构造特征和地壳结构特征、主要断裂构造特征以及莫霍面的起伏特征进行了精细分析和细致研究．从地球物理平面场特征出发建立了岩石圈构造三维框架。研究结果表明，这样的研究思路准确、方法得当．结论可靠；沿该剖面，把可解译的断裂分为Ⅲ级：Ⅰ级为超岩石圈断裂；Ⅱ级为壳断裂；Ⅲ级为盖层断裂。依据地球物理特征，准确揭示了库区的断裂构造特征，达到了预期效果。     

Metamorphism in Archaean greenstone belts: calculated fluid compositions and implications for gold mineralization

An inescapable consequence of the metamorphism of greenstone belt sequences is the release of a large volume of metamorphic fluid of low salinity with chemical characteristics controlled by the mineral assemblages involved in the devolatilization reactions. For mafic and ultramafic sequences, the composition of fluids released at upper greenschist to lower amphibolite facies conditions for the necessary relatively hot geotherm corresponds to those inferred for greenstone gold deposits (X_CO2= 0.2–0.3). This result follows from the calculation of mineral equilibria in the model system CaO–MgO–FeO–Al₂O₃–SiO₂–H₂O–CO₂, using a new, expanded, internally consistent dataset. Greenstone metamorphism cannot have involved much crustal over-thickening, because very shallow levels of greenstone belts are preserved. Such orogeny can be accounted for if compressive deformation of the crust is accompanied by thinning of the mantle lithosphere. In this case, the observed metamorphism, which was contemporaneous with deformation, is of the low-P high-T type. For this type of metamorphism, the metamorphic peak should have occurred earlier at deeper levels in the crust; i.e. the piezothermal array should be of the ‘deeper-earlier’type. However, at shallow crustal levels, the piezothermal array is likely to have been of ‘deeper-later’type, as a consequence of erosion. Thus, while the lower crust reached maximum temperatures, and partially melted to produce the observed granites, mid-crustal levels were releasing fluids prograde into shallow crustal levels that were already retrograde. We propose that these fluids are responsible for the gold mineralization. Thus, the contemporaneity of igneous activity and gold mineralization is a natural consequence of the thermal evolution, and does not mean that the mineralization has to be a consequence of igneous processes. Upward migration of metamorphic fluid, via appropriate structurally controlled pathways, will bring the fluid into contact with mineral assemblages that have equilibrated with a fluid with significantly lower X_CO2. These assemblages are therefore grossly out of equilibrium with the fluid. In the case of infiltrated metabasic rocks, intense carbonation and sulphidation is predicted. If, as seems reasonable, gold is mobilized by the fluid generated by devolatilization, then the combination of processes proposed, most of which are an inevitable consequence of the metamorphism, leads to the formation of greenstone gold deposits predominantly from metamorphic fluids.     

Paleoproterozoic Extensional Structure and Its Controlling on Mineralization in the East of Liaoning Province

IntroductionThe area of eastern Liaoning is an importantmetal and nonmetal metallogenetic district in China,and the Liaohe group is one of the most importantstrata that hosts Pb, Zn, Au, B and Mg etcstratabound deposits. Up to now many geo1ogistssuch as Z…     

山东内生金矿矿床谱系及其致矿地质异常

矿床谱系是对成矿多样性的理论概括,而成矿多样性又是由不同级别、不同性质的致矿地质异常决定的.本文论述了山东省内生金矿矿床谱系及其致矿地质异常.     

元岭金矿蚀变破碎带特征及其找矿意义

根据对元岭金矿三条蚀变破碎带一般地质特征、微量元素特征的对比研究，并借鉴邻近矿区蚀变破碎带的矿化特征，本文阐明了元岭蚀变破碎带矿化的有利构造部位，总结了蚀变破碎带特征与矿化强度之间的关系，指出蚀变破碎带的矿化蚀变元素为中低温组合，矿化蚀变愈强则参与元素的种类愈多、数量愈大。围岩性质对矿化蚀变有一定影响，围岩中的易迁移亲铜元素和亲硫铁族无素对矿化有利。据此，为进一步成矿预测、评价蚀变破碎带的含矿性提供依据。     

广西难处理金矿固化焙烧氰化提金试验

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