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。     

Tectonic Setting and Nature of the Provenance of Sedimentary Rocks in Lanping Mesozoic- Cenozoic Basin： Evidence from Geochemistry of Sandstones

The geochemical composition of sandstones in the sedimentary basin is controlled mainly by the tectonic setting of the provenance, and it is therefore possible to reveal the tectonic setting of the provenance and the nature of source rocks in terms of the geochemical composition of sandstones. The major elements, rare-earth dements and trace elements of the Mesozoic-Cenozoic sandstones in the Lanping Basin are studied in this paper, revealing that the tectonic settings of the provenance for Mesozoic-Cenozoic sedimentary rocks in the Lanping Basin belong to a passive continental margin and a continental island arc. Combined with the data on sedimentary facies and palaeogeography, it is referred that the eastern part of the basin is located mainly at the tectonic setting of the passive continental margin before Mesozoic, whereas the western part may be represented by a continental island arc. This is compatible with the regional geology data. The protoliths of sedimentary rocks should be derived from the upper continental crust, and are composed mainly of felsic rocks, mixed with some andesitic rocks and old sediment components. Therefore, the Lanping Mesozoic-Cenozoic Basin is a typical continental-type basin. This provides strong geochemical evidence for the evolution of the paleo-Tethys and theb asin-range transition.     

云南祥云金厂箐金(铜)矿床的成矿流体特征及流体来源

金厂箐金(铜)矿床原生流体包裹体和流体氢氧同位素的研究成果表明该矿床改造期早阶段流体为中温、中等盐度，形成于酸性和相对较还原环境的硫酸盐型热卤水。晚阶段流体为低温、低盐和相较于早阶段形成压力更低和更氧化环境的氯化物型热卤水。成矿流体水来源于(晚阶段)或主要来源于(早阶段)雨水源地下水，其同成矿时的原始雨水(δ^18O=-15．3‰)相比，氧同位素组成要重12‰～17‰，是在水岩比(W／R)较小的条件下与围岩水岩反应进行同位素交换的产物。     

~(40)Ar-~(39)Ar Dating of Quartz from Ore in the Baiyangping Cu-Co Polymetallic Ore-Concentrated Area, Lanping Basin, Yunnan

40Ar-39Ar fast neutron activation age spectrum of quartz in ore collected from the Baiyangping Cu-Co polymetallic ore-concentrated area, Lanping Basin, is saddle-shaped. The plateau age, minimum appearance age and isochron age shown on the spectra are 56.53±0.43 Ma, 55.52±1.78 Ma and 55.90±0.29 Ma respectively. The age data are consistent with each other within 1σ uncertainties. Because the given initial 40Ar/36Ar value of 294.7±1.14 is very close to Nier's value (295.5±5), both plateau and isochron ages may be considered as the forming time of quartz. So the age of 55.90-56.53 Ma represents the forming age of ore deposits. It is obvious that the ore deposits were formed during the Early Himalayan period.     

Element—Assemblage Zoning Features of Gold Deposis in the Cambrian Silicalite Formation,Western Qinling

The gold deposits,occurring in the south subzone of western Qinling,are the only typical and important strata-bound gold deposits,which are associated with submarine exhalative sedimentation.The gold deposits include the La‘erma ore deposit,the Qiongmo ore deposit and the Yaxiang ore occurrence.They are hosted i the Cambrian silicalite formation composed of black chert and slate.The presence of typical chert offers important evidence to evaluate the possible submarine exhalative system and its role in the formation of the gold deposits,which are closely associated with peroclation and diffusion in the horizontal,vertical and axial directions,Element-assemblage zonation is clearly seen due to differences in element concentrations in different directions,Such a zonation makes gold.selenium,uranium,copper,stibium,molybdenum,mercury,etc,precipitate in the form of simple or composite orebodies.The establishent of the element-assemblage zonation is highly helpful for evaluating directly the metallogenesis of gold deposits.     

西秦岭大地构造演化与金成矿带的分布

本文以板块构造理论分析和恢复了西秦岭大地构造的演化特点；以西秦岭层控金矿床区域地质构造演化研究为前提，系统研究了西秦岭地区金成矿带与裂陷活动的关系。进而从宏观上论述了研究区成矿地质背景，提出西秦岭地区三个金成矿带与古生代以来的三次裂陷活动有关。这一认识无疑对该区金矿研究与找矿提供了一个新的方向与思路。     

层控金矿床中一种新类型矿石建造——Au-Se矿石建造

近年来,作者在研究阿坝地块层控金矿床的成矿规律时,发现了一种新类型的含金矿石建造——Au-Se矿石建造。拉尔玛层控金矿床位于西秦岭南亚带白依沟背斜西段的倾没端。矿床赋存于寒武系太阳顶群地层中,受层位控制明显。太阳顶群由碳质硅岩和碳质板岩组成,厚度最大可近千米,其中碳质硅岩     

河南前河蚀变岩型金矿石英热释光与金矿化研究

石英是金矿床中最重要的脉石矿物,其化学组成和晶体结构高度稳定,用低灵敏度的研究方法很难得出提供地质成因信息的晶体结构参数的微小变化,但热释发光分析在某些情况下却能取得较好的效果.在利用石英热释光特征所提供的的微观矿物学信息辅助解决矿脉含金性评价、矿床成因类型鉴别及成矿阶段划分等方面均取得了一定成效(陈光远等,1984,1989;李胜荣等,1993).本文对河南前河构造蚀变岩型金矿床各类型蚀变岩中石英热释光特征进行了研究,总结了各类型蚀变岩特别是黄铁矿绢英岩化安山岩和矿石石英的热释光特征与早期、晚期蚀变岩中的石英的特征差异.     

甘肃岗岔—克莫地区蚀变岩特征与找矿预测

岗岔—克莫金矿区位于西秦岭北缘夏河—合作成矿带,具浅成低温热液型矿床特征,初步显示深部可能具有斑岩成矿系统存在。利用短波红外光谱矿物分析技术对岗岔—克莫金矿区蚀变岩特征的研究表明,矿区内发育的蚀变矿物主要有白云母、伊利石、蒙脱石、高岭石、地开石、绿泥石、绿帘石和次生石英等。近矿蚀变类型主要为绢英岩化。矿区内以下家门沟口为中心向外依次发育了中心带(绢英岩化带)、过渡带(泥化带)和外围带(青磐岩化带)。此外,伊利石结晶度以下家门沟口为中心向外具有明显的降低趋势。研究结果指示下家门沟口可能是矿区的热液活动中心。