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。     

“狗头金”的价值

“狗头金”，特别是体大、造型好的“狗头金”，与原生金矿中的天然块金一样都是稀世珍宝，不但具有很高的科研价值，而且具有重要的收藏，观赏和科普宣传价值及巨大的经济价值。     

中国“狗头金”刍议

我国已在13个省（区）40处发现“狗头金”百余块,是最早发现“狗头金”的国家。“狗头金”形状复杂,千姿百态,普遍具有明显的次生长特征,砂金的粒度一般较原生金粗,成色比原生金高,“狗头金”形成后还会经过新的离散,聚合作用,总的趋势是结构向致密化,形成向简单化,质地向纯净化方向发展,经风化或冰川崩落、搬运、沉积的含金矿物集合体（天然块金）也是“狗头金”形成的来源之一。     

狗头金成因新认识

依据金矿体中存在大块金金狗大头金与原生金矿体关系密切和表生条件下金的增生程度十分有限以及表生成因说无法解释的一系列疑点为基础，对狗头金的成因进行了探讨，指出存在于表生环境中的狗头金是原生块金在表生条件下经改造并发生有限增生的结果，狗头金发育地区应存在或曾存在原生金矿体。     

中国狗头金分布特征与成因讨论

中国大部分狗头金分布在湖南、四川、黑龙江、青海与山东五省。狗头金分布与水系有密切关系。狗头金可划分为两大类成因类型:表生成矿型(物理风化、化学溶解、再生-齐汞化)与原生成矿型(原生金块与原生改造)。含金地貌与新构造运动在成矿作用中占有重要地位。     

浅谈青海发现“狗头金”

从1983年起,青海多次在砂矿中发现“狗头金”。1983年在海西发现一块重达3561.407g的“狗头金”,1986年又发现一块毛重7709.55g的罕见块金,为我省金块之最。继1987年发现的550g和650g的块金后,1988年在大通又发现一块2100g重的块金。     

对孔隆沟砂金矿及“狗头金”成因的探讨

孔隆沟砂金矿及“狗头金”是在PH值为中偏酸性的条件下,由金源层中呈分散状态的微细金粒溶解、迁移,在中偏碱性的环境中沉淀增生,其次生金粒经金的自身胶结作用不断再加大,形成盛产“狗头金”的砂金矿床。     

关于金的表生溶液迁移问题

一般认为,沉积岩中的工业金矿床只有砂金和砾岩金矿,它们都是纯机械搬运作用的结果。但事实表明,除机械作用外,化学作用、生物作用和物理化学作用对金在沉积物中的聚集都是不可忽视的。 1.“狗头金”的形成与砂金矿的再生澳大利亚和苏联南乌拉尔是世界上发现“狗头金”最多的两个地区,南乌拉尔曾获得俄国最大的的“狗头金”(36公斤)。澳大利亚曾发现     

中国西部“金三角”地区狗头金形成机理和生物——化学聚金工程

由地质矿产部成都地质矿产研究所负责,中国科学院成都生物研究所参加合作的国家自然科学基金和地质行业基金联合资助的中国西部“金三角”地区狗头金形成机理和生物—化学聚金工程”经过三年的努力,取得了显著成绩。 中国西部金三角地区(川西藏东及青—甘—陕南部)广泛分布的砂金及狗头金(块金),主要产于青藏高原及周缘切割带的新生代山间盆地边缘的河流支谷或阶地及坡积物中。如四川西部白玉山孔隆沟中下游一段长400m,宽50m的“弹丸之地”,近5年来挖掘出至少15块500g以上的狗头金(大块金)。松潘漳暗和盐源     

益阳极品狗头金形态之谜

2011年5月27日，一部小制作影片《狗头金》悄然上映。影片的内容很简单，也很老套，主要讲述了5个穷困潦倒的淘金汉子，为了各种目的，冒着种种危险结伴进山淘金。     

室温条件下微生物环境中块金生长机理的实验研究

室温条件下,用真菌、硅藻、固氮菌及芽孢杆菌等不同微生物,经３个月至１８个月的时间,可将砖红色的海绵金培育成片状、丝状及粒状的Ａｕ颗粒,这表明在表生条件及微生物环境中,Ａｕ可以被活化、迁移、再生长、测定结果表明,培养液中的Ａｕ质量浓度与其中的Ｈ２Ｏ２质量浓度有正相关关系;而且,Ａｕ和Ｈ２Ｏ２质量浓度高的样品,其中的金粒生长速率也快,说明表生条件下块金的生长与溶液中的Ｈ２Ｏ２质量浓度密切相关。     

Evaluation of skewed exploration data—the nugget effect

Histograms of mining exploration data are often skewed, with many low assays and fewer higher values. During evaluation, causes of the skew should be investigated. If it is due to large-scale gradation in the mineral content of the deposit, geostatistical evaluation is indicated. If. however, nugget effects or reduction and subsampling errors are large, geostatistical approaches are at a disadvantage.Nugget effects may arise from a practical impossibility of taking sufficiently large field samples: reduction and subsampling inadequacies may be difficult to detect and overcome during the urgencies of an exploration campaign. Means have been devised to measure variances due to nugget effect and subsampling error and remove them from the data.     

Gold nugget morphology and geochemical environments of nugget formation,southern New Zealand

Gold nuggets (centimetre scale) have formed in a supergene alteration zone on hydrothermal gold deposits, and occur intergrown with quartz and iron oxyhydroxide pseudomorphs after sulphide minerals, and along fractures in quartz and host rocks. The supergene alteration was driven by groundwater-driven water-rock interaction near to a regional unconformity beneath fluvial sediments, and involved clay alteration and oxidation that extended up to 50 m below the unconformity. Oxidation of pyrite and arsenopyrite produced temporary thiosulphate ligands that mobilised microparticulate gold encapsulated in the sulphide minerals. The nuggets have some crystalline form, and internally they consist of anhedral grains, elongated gold plates, and intimate intergrowths of gold and iron oxyhydroxide. Nugget surfaces have further micron scale overgrowths of microparticulate gold, gold plates, and gold crystals. Nuggets were eroded and recycled into nearby proximal Miocene quartz pebble conglomerates, where they concentrated in placers near the basal unconformity. Later recycling transferred gold into Pleistocene fluvial channels. Gold dissolution and redeposition as plates and crystals occurred on the exterior surfaces of placer gold particles, with little change in mass. All groundwater maintained high pH throughout the geological history because there was sufficient calcite in the basement rocks to neutralise any acid generated by pyrite oxidation. Hence, gold mobility in sediments was driven by thiosulphate complexes as for the in situ nuggets, albeit with lower dissolved sulphur concentrations. Despite aridification of the climate in the late Cenozoic, with resulting localised high dissolved chloride concentrations, chloride complexation did not contribute to gold mobility.     

Crystalline gold in soil and the problem of supergene nugget formation: Freezing and exclusion as genetic mechanisms

Many of the world's richest gold placer deposits now occur in cold regions despite differences in their climatic history. It therefore seems possible that there may be some fundamental connection between freezing climates and the local chemical behavior of gold in the weathering cycle. This hypothesis, along with the problematical occurrence of gold as euhedral crystals in arctic gravel and soil placers, has led me to review low temperature phenomena that may bear on the geochemistry of gold.Several effects which may influence the weathering of natural gold-bearing rocks, the chemical complexation of gold, and its subsequent mobility and deposition appear to be strongly connected with freeze action. The exclusion of dissolved solutes, solute gases, and particles from ice, subjects rock and soil minerals to increased corrosion from thin, unfrozen, adsorbed water films which remain at particle surfaces throughout the freezing of rocks and soils. The preferential exclusion of cations (over anions) from growing ice crystals creates charge separations and measurable current flow across waterice phase boundaries in freezing soil — a phenomenon which leads to troublesome seasonal electrolytic corrosion of pipelines buried in soil; this phenomenon may also favor the dissolution of normally insoluble metals such as gold during geologic time periods. The ice-induced accumulation of clays, organic acids, bacteria, and other organic matter at mineral surfaces may also speed chemical attack by providing a nearby sink of alternate cation-binding sites and hence rapid removal of liberated cations from solution. The latter mechanism may be operative in both the dissolution and redeposition of gold.These physical, chemical, and electrical effects are favorable to the dissolution of rocks (in addition to frost shattering) and to the dissolution, mobilization, and redeposition of gold and other noble metals and must therefore contribute significantly to the behavior of gold at low temperatures. The occurrence of large numbers of gold placer deposits in northern Canada, Alaska, and Siberia may thus be due in part to the low temperatures common to these regions.     

胶东焦家金矿床钾长石成因及成矿意义

焦家金矿属于蚀变岩型金矿,围岩蚀变发育,是我国储量最大的金矿床之一。该文对蚀变带中的钾长石的赋存状态、化学成分进行了分析研究,并与未蚀变的玲珑岩体中的钾长石进行对比。认为焦家金矿床主要存在三种成因类型的钾长石,即原生钾长石（岩浆成因）、高温热液钾长石、低温热液钾长石。结合前人的研究成果,探讨了热液钾长石的形成与成矿意义。     

西秦岭—松潘金三角地区金矿带划分及特征

西秦岭—松潘地区是我国西部重要的卡林型金矿成矿的集中区 ,依据其成矿规律可划分为同仁—夏河—岷县金成矿带 ;青海军功—甘肃尕海—舟曲—成县南金成矿带 ;玛沁—玛曲—南坪金成矿带 ;青海德尔尼—积石山—平武金成矿带 ;青海达日—斑马—马尔康金成矿带 ;四川松潘哲波山—文县—康县金银铜成矿带等 6个重要的金矿成矿带     

中国石英脉型金矿床地质特征

石英脉型金矿床是指含金地质体为（含钾长石）石英脉的一类金矿床,是中国金矿床工业类型中的重要类型矿床.综合论述了石英脉型金矿床的含金地质体及矿体的空间展布特征、矿石矿物组合特征、矿石微量元素组合特征及围岩蚀变特征,形成地质环境及成因,总结了该类金矿床矿石中金的赋存状态、赋存特点及矿石的选冶条件和流程.