秦岭地区砂金分布特征与成矿机理

秦岭地区砂金矿床大部分分布在嘉陵江、汉水及其它们的支流流域。总结了砂金矿床分布特征,并将３种类型进行了对比。系统地对矿源、搬运、储存和富集的成矿模式、成因机理进行了研究。地貌与产构造运动在成矿中占有重要地位。     

西藏班公湖-怒江成矿带中段砂金成色特征

该区砂金成色具有明显的不均一性，继承性和后期改造性。成色变化范围大（531．48－1000），具有粒度越大成色越高的趋势，区同西部砂金矿床的溶蚀系数小于1．03，为近原生源砂金，东部的1．03－1．10，为中近原生源砂金，崩纳藏分布于1．10，为远原生源砂金。自然金化学成分研究表明其原生金矿为中低温热型金矿床，那朗沟一带的燕山晚期花岗岩体内部有找到原生金矿床的可能。     

黑龙江省砂金的铅同位素地质特征

对黑龙江省８２件砂金样品及与之对比的１６件岩金样品进行铅同位素测定,结果表明它们与Ｃ１及Ｃ２省中生代岩浆岩的长石铅平均值十分接近。在部分铅来自造山带,少量源自地壳,表明砂金矿多来源于中生代岩浆活动有关的金矿床。铅同位素的三维拓扑图解亦可用于估计原生岩金矿的剥蚀程度及示踪砂金的原生源。     

南印怀纳德金矿区尼兰布尔河谷中高纯度砂金的形成

印度南部怀纳德金矿区尼兰布尔河谷中的砂金颗粒以纯度非常高（９８５～１０００）为其特征。砂金的核心成分贫银，颗粒大和微型生长形式都可以与风化基面中的红土剖面有关的金粒对比。根据与本区原生矿床，表生矿床和次生矿床有关的金粒的形态和化学演化，鉴别了高纯度砂金矿的两阶段演化过程，它表明原生矿脉中的金活化转移，化学纯化并重新富集在红土剖面中，对金被迁移到水系中去之前纯度的增高和颗粒的生长都有影响。在河水搬运     

藏北砂金成矿富集规律及找矿标志

根据砂金时空分布规律和地质特征，论述了砂金矿控矿因素、成矿机制、建立了砂金矿找矿标志，对质勘查工作具有重要的参考利用价值。     

江西省九瑞地区金矿床类型,主要特征成矿序列及控矿因素探讨

九瑞地区是江西重要的内生金属成矿区之一。本文综合分析了近年来区内找矿科研工作的资料；划分了区内金矿的类型、成矿序列；简述了主要类型代表性矿床的地质特征。在此基础上探讨了区内地层、构造、岩浆岩对金矿的控制作用及时间上的分布规律，指出了志留纪、泥盆纪、石炭纪和二叠纪为金矿成矿的预基期，侏罗纪、白垩纪为主导期，第四纪为改造期，以及在各个时期金的成矿作用各具特色、浙次叠加发展、富集的规律。     

藏北地区砂金矿特征及找矿方向初探

藏北地区砂金矿矿质来源于中酸性岩浆岩接触带，沉积地层不整合接触带及硅化岩带，具物源近，成矿时代新的特点。班公湖－怒江地缝合线及其两侧的羌塘隆起带和冈底期－念青唐古拉陆块，是区内最有利的砂金成矿区。     

砂金及"狗头金"次生增生的有限性

对砂金、“狗头金”的次生增生边宽度，砂金和“狗头金”的粒度和成色与原生金矿体的自然金粒度和成色的对比结果表明，砂金、“狗头金”在表生条件下的次生增生程度是十分有限的。对有限增生的原因进行了分析，认为可能与H2O2、微生物等对微细粒金具有双重作用有关，即其对微细粒金的溶解及再生均起作用。从而得出砂金及“狗头金”应由原生金矿体中的富金集合体（大块金及金的巨晶）在表生条件下遭受改造并发生有限增生所形成。     

河南省砂金矿床地质特征

河南省砂金矿床广泛分布于黄河、长江两大水系的支流中,具代表性的有淅川寺湾及嵩县高都川两矿床,其成因类型分属于河床-河漫滩型与阶地型两大类。矿体展布形态与全新统地层分布状态一致,为近水平沿现代河流边部赋存的长条带状。在地质找矿方面,在两大水系交汇处、河流地形的缓坡以及河流的内湾一侧均为寻找砂金矿床的有利区段。     

西藏尼玛砂金矿中金和银的提纯与精炼

为提纯与精炼西藏尼玛砂金矿中的金和银，在王水介质中制作供还原的Au液，选择草酸作为还原剂很容易将Au还原，而且不与其他金属离子反应。砂金的提纯与精炼要经还原Au液、排除HNO3和砂金的2次溶解及Au的还原。尾渣以NaCO3、硼砂、KNO3为配料在焦炭炉中进行熔炼和泼珠，进而分离出金、银。在提取银的操作中，采用饱和NaCl水溶液。制定的金、银王水法提纯与精炼流程所产出金锭的成色大于等于99．99％，银锭成色大于等于99．90％。     

西藏普兰县马攸木砂金矿床的发现及其意义

1999年在雅鲁藏布江缝合带西段马攸木地区首先探查到砂金异常,进而通过预查、普查和详查,发现了砂金储量居目前西藏之首的马攸木砂金矿床。该矿床Ⅰ号矿体长为14196.3m,平均宽度为126.61m,平均厚度为11.25m,加权平均品位为0.5116g/m3,砂金资源总量属大型。介绍了Ⅰ号矿体砂金的形态与粒度、成分和成色。马攸木砂金矿床的发现,对西藏地区及古地中海—喜马拉雅成矿域的找矿与成矿理论研究具有重要意义。     

西藏崩纳藏布砂金矿地质特征及找矿方向

通过对区域地质背景、第四纪典型地貌及矿床地质特征等的研究，发现崩纳藏布砂金矿具有成矿时代新、成矿期短、物质来源多样性等特点。成矿过程明显具有2个阶段：早期可能与斑岩型铜－金－多金属矿床有关，含Au配合物近距离活化、迁移，在适宜的地方堆积成矿；晚期在原地吸收侧向补给的第四系含Au沉积物，次生富集成为富矿。     

Indicative features of placer gold for the prediction of the formation types of gold deposits (east of the Siberian Platform)

Prediction and search for gold deposits in the east of the Siberian Platform are problematic because the study area is overlain by a thick cover of MZ-KZ deposits. Search for gold deposits by the largest geological institutions using conventional methods have not yielded positive results, because the main attention was focused on the discovery of ancient gold-bearing conglomerates of the Witwatersrand type and on the evaluation of the gold ore potential of basic magmatism. Typomorphism of placer gold bears huge information about the genesis of native gold, both its primary endogenous origin and its exogenous transformation, which makes it possible to identify the formation type of mineralization, increases the reliability of the prediction of gold deposits, and ensures their purposeful search in the platform areas. The revealed indicative features of placer gold made it possible to substantiate the formation of the gold ore sources of Precambrian low-sulfide gold-quartz, gold-iron-quartzite, porphyry gold-copper, and gold-PGE mineralization and Mesozoic gold-silver, gold-rare-metal, and gold-sulfide-quartz mineralization in the east of the Siberian Platform. We have established that high-fineness placer gold with microinclusions of pyrite, arsenopyrite, quartz, and carbonates with recrystallized structures and lines of plastic deformation is specific to the ore sources of low-sulfide gold-quartz mineralization. A high content of Cu (up to 4%) in flaky high-fineness gold is one of indicators of porphyry gold-copper mineralization. The angular shape of gold grains, the fine fraction and high fineness of gold, its completely recrystallized and regrown internal structure, and the permanent presence of Fe, Bi, and Cu microimpurities and hematite, ilmenite, and corundum microinclusions are typical of gold-iron-quartzite mineralization. Flaky and laminated high-fineness gold particles with steady Pt, Pd, and Ni impurities and Pt-mineral phases and Au-Pt intergrowths in them testify to the ore sources of gold-PGE mineralization. Laminated and cloddy gold fractions of > 0.25-2.0 mm, the medium and low fineness of gold, its single-crystal or, sometimes, porous internal structure, the wide range of microimpurities (Pb, Zn, As, Sb, Cu, Te, etc.), and microinclusions of native Ag, adularia, Sr-barite, and calcite are indicators of gold-silver mineralization. Laminated, dendritic, and cloddy-angular gold grains, wide variation in gold fineness (307-950‰), and the presence of microinclusions of native bismuth, maldonite, arsenopyrite, and silver tellurides are indicative of gold-rare-metal mineralization. Laminated and cloddy gold grains, their size varying from dust to > 0.25 mm, their mono- and coarse-grained internal structure, wide variation in gold fineness (600-900‰), and the presence of Hg microimpurities (up to 6% and more) and microinclusions of quartz, calcite, pyrite, arsenopyrite, tellurides, selenides, and REE phosphates point to gold-sulfide-quartz mineralization. The established placer gold indicators of the particular formation types of ore sources in the east of the Siberian Platform made it possible to predict Precambrian gold deposits with low-sulfide-gold-quartz mineralization similar to the Kirkland Lake and Porcupine mines and gold deposits with Mesozoic gold-silver mineralization similar to the Cripple Creek mine. The developed criteria for determining the types of mineralization by indicative features of placer gold give an insight into the ore genesis and can be successfully applied to prediction and search for gold deposits and to evaluation of their gold resources.     

藏北羌塘小盆湖-拉雄错砂金矿带地质特征

以小盆湖砂金矿床为典型的一系列砂金矿床、矿点在藏北羌塘中部构成一个呈东西向的砂金矿带,笔者1999年首次将其命名为"藏北羌塘小盆湖-拉雄错砂金矿带"。通过对小盆湖砂金矿床基岩地质、地貌、第四纪地质、矿床类型、成因类型、矿体特征、砂金特征的全面介绍及与该带其它砂金矿床、矿点的对比,结合区域地质背景,认为前泥盆系阿木岗群和石炭系中的火山岩层位是主要矿源层。此后若干不同时期的沉积不整合界面,都表征着其下古风化壳、其上底部碎屑岩的含金物聚源区可以直接或经改造就近形成金矿矿床。羌塘中央隆起带及其两侧和东西方向石炭系分布区具有广阔的金矿找矿前景。