西藏甲马铜多金属矿床远景预测

近年研究表明，作为西藏境内少数几个大型矿床之一的甲马铜多金属矿床先后经历了燕山晚期海底喷流积积成矿作用和喜马拉雅期斑岩型成矿作用，相应形成矿区层状主矿休和斑岩型矿体。矿区地质特征、主成矿元素空间分布规律分析后认为：矿区东、西段各存在一个喷流中心，与之相关的层状矿体及深部脉状、网脉状矿体是今后找矿的重点靶区；喜马拉雅期斑岩成矿作用在区域及矿区内均有显示，具有不可忽视的成矿潜力。     

成矿系统与矿化网络研究

成矿系统研究体现了系统观和历史观的结合，是现代矿床学的一个发展趋势，本文简要总结了成矿系统及演化论的几个要点，即（1）按构造动力体制划分成矿系统大类；（2）我因耦合，临界转换的成矿作用机理；（3）矿床系列和异常系列构成的矿化网络；（4）矿床形成-变化-保存的演变过程，在此基础上，作者提出矿化网络是在一个成矿系统中形成的诸类矿床和相关异常的时空分布和结构，它是成矿系统的具体内容的表达。对成矿系统的深入研究应从矿化网络入手，着重在以下几个方面；（1）各类矿床的发育程度；（3）各类矿床的空间关系；（3）各类矿床的时间关系；（4）各类矿床的成因联系；（5）各类矿床被改造的情况。这些都是矿床学和找矿预测研究的基础内容。     

小热泉子铜矿床成矿过程分析

新疆小热泉子铜矿床主要产于下石岩统小热泉子组一套滨，浅海相火山-沉积组合夹不等量正常沉积组合的岩石中，矿体在较深部呈层状，似层状而在浅部呈脉状，构成立交桥式矿化格架，通过基础地质，矿床地质及地球化学特征研究，认为小热泉子铜锌矿床的形成过程至少经历了4期6个阶段；即喷流沉积-成岩成矿期，混合热液叠加改造期，构造改造期和表生风化期，主成矿期为热液叠加改造期。     

中国首例铁氧化物-铜-金-铀-稀土型矿床的厘定及其成矿演化

通过对拉拉矿床物共生组合、矿物生成顺序、矿石特征的研究，发现其矿石物以磁铁矿为主，铁和铜的硫化物次之，并含有大量稀土矿物和自然金。拉拉矿床至少经历了两期成矿作用：早期为区域变质成矿作用，晚期为热液成矿作用。早期形成Fe-REE-P矿化，晚期为Cu-Mo-Au-Co-(U)矿化。根据这些特征，首次指出该矿床属于铁氧化物-铜-金-铀-稀土型矿床，而不是以往所称的块状硫化物型铜矿。     

地幔热柱及其成矿作用研究

成矿作用研究表明 ,在地球的演化历史中 ,成矿数量有从少到多 ,聚矿能力有由弱到强的演化趋势。中生代为全球规模的成矿大爆发阶段 ,究其原因可能与地球的发展演化密切相关。地球形成的早期 ,由于地球物质尚未充分分异 ,成矿强度不大。当然 ,有部分在地球演化早期形成的矿床 ,在后来的多次构造改造过程中被改造迁移 ,甚至消失。中生代地球进入了一个强烈的地幔热柱活动时期 ,聚集于D”层及外核的成矿物质可通过地幔热柱多级演化向上迁移 ,并在幔枝构造的有利构造扩容带中成矿 ,幔枝构造则成为中生代主要的成矿控矿构造类型     

Geochemical stream sediment survey in Winder Valley, Balochistan, Pakistan

A pilot scale geochemical survey of sediments from the Winder Stream (SW Pakistan) and its tributaries was carried out. The Winder Stream mainly receives sediment from the southern extensions of the Mor and Pab Ranges in the District of Lasbela (Balochistan). In these two mountain ranges, rocks from Jurassic to Cretaceous age are exposed. Rocks of the Ferozabad Group comprise of carbonates and siliciclastics of Lower–Middle Jurassic age and occupy the dominant part of the Mor Range. These strata host syngenetic and epigenetic Zn–Pb–Ba mineralizations of Stratiform Sediment-Hosted (SSH) and Mississippi Valley Type (MVT) deposits.Quantitative estimates of mobile and immobile elements were made from active stream sediments of the Winder stream and its tributaries. The samples were analyzed for Ag, Zn, Pb, Cu, Ni, Co, V, Mn, Fe and Ba using atomic absorption spectroscopy. The abundance of these elements is discussed in relation to local geological conditions such as bedrock, climate, weathering, mobility and pH of the dispersing waters. A number of Zn anomalies have been distinguished in the study area. Kharrari (Zn, 360 ppm), Sand (Zn, 340 ppm) and Draber (Zn, 210 ppm) are demarcated as new areas for Zn mineralization. The present study also indicates prospects of Ag, Cu and V in the rocks of the Mor Range.Relationships between various elements have been identified from scattergrams and reflect genetic associations. Whereby the positive correlation between Cu–Zn (0.55, n=18) and Cu–Pb (0.63) is related to possible sulphide mineralization.     

川西连龙含锡花岗岩的时代与形成构造环境

通过岩石地球化学和Rb Sr同位素研究 ,发现川西连龙花岗岩是富含Sn、Ag多种成矿元素的高K钙碱性岩体 ,地球化学上显示出A型花岗岩特点。 4个全岩样品给出的Rb Sr等时线年龄为 87± 1Ma,相关系数R =0 .9988,Isr=0 .70 95。结合构造环境分析 ,查明该岩体是燕山运动晚期 ,在弧陆碰撞造山之后陆内伸展阶段 ,主要由地壳富泥质岩石部分熔融形成。     

Gold Mineralization and Occurrence of Sinter in the Hoshino Area, Fukuoka Prefecture, Japan

Abstract. Several epithermal gold deposits occur in the Hoshino area, which is located in the western end of the late Cenozoic Hohi volcanic zone, north‐central Kyushu, Japan. The area is characterized by intermediate to felsic extrusive rocks of Pliocene age. In the Hoshino area, the shallow manifestation of the hydrothermal activity is exposed on the surface. Several outcrops of sinter are still preserved on the top of hydro thermally altered volcanic rocks, and high‐grade gold‐bearing quartz veins occur on the surface at lower levels. The hydrothermal alteration resulted into well‐developed alteration zones. The zonal alteration pattern, primarily of near‐neutral pH type, is characterized by the outer smectite zone of a lower temperature, and the inner mixed layer minerals zone of a higher temperature. Quartz vein‐related or fracture‐controlled alteration, is represented by the occurrence of interstratified illite/smectite and K‐feldspar, suggesting a potassium‐enriched alteration. The mineralization in the Hoshino area is recognized on the surface by the occurrence of gold‐bearing quartz veins distributed mainly in the mixed layer minerals zone. The fracture system related to the gold mineralization is mainly characterized by NW‐SE trend. The alteration pattern and the mineralogical composition of the veins suggest that the mineralizing fluids had near‐neutral pH and the mineralization is of low‐sulfidation‐type. Fluid inclusion data and textures observed in quartz veins indicate that gold precipitated during boiling. The chemical composition of quartz veins shows that high‐grade gold‐bearing quartz veins are characterized by higher content of Al₂O₃, K₂O and Rb. Several outcrops of silica‐sinters are distributed on the top of the mixed layer minerals zone. Although their structures are not very well preserved, because of later silicification, the Hoshino sinters still show characteristic textures identical to those observed in modern sinters, such as the presence of plant fossil incorporated into the sinters, the strongly developed depositional laminations and the columnar structures perpendicular to the depositional surfaces. Quartz is the only silica mineral constituting the Hoshino sinters presently. The conversion of amorphous silica into quartz was probably governed by higher temperatures resulting from later hydrothermal activity. This later hydrothermal activity is reflected by the intense silicification affecting mainly the lower parts of the sinters and also by the presence of quartz veins cutting the sinters. The distribution of sinters in the Hoshino area is very significant. The presence beneath the sinters of concealed high‐grade gold‐bearing quartz veins should be highly considered and exploration work is strongly suggested.     

Timing of Fracture Formation and Duration of Mineralization at the Hishikari Deposit, Southern Kyushu, Japan

Abstract. The Hishikari epithermal gold deposit consists of the Honko-Sanjin zone and Yamada zone. On the basis of observed crosscutting relationships of veins, vein system in the Hishikari deposit was classified into the early and late veins. They differ from orientation, width, control by unconformity, the amount of displacement and structural features, but have similarity in gold grade and Au/Ag ratios. K-Ar ages are presented for the classified veins to clarify timing of fracturing and duration of mineralization.
Age determination revealed that the early veins in the Honko-Sanjin zone range from 0.86 to 1.11 Ma and that the late veins range from 0.73 to 0. 84 Ma. The economically most important mineralization in the Hishikari deposit occurred around 0.90 Ma in a very short period (about 0.05 million years).
The distribution of mineralization age in the whole Hishikari deposit, occurrences of slickensides and ground water temperatures imply that mineralization lasted longer in the southern part of the deposit. As compared the early veins with late veins, structural changes including width, strike, dip and vein characteristics occurred at around 0.85 Ma.     

云南兰坪北部铜多金属矿化区成矿流体流动与矿化分带——流体包裹体和稳定同位素依据

滇西兰坪盆地北部发育了一类受逆冲推覆构造控制的浅成热液Cu—Ag—Pb-Zn矿化，形成了白秧坪、富隆厂、吴底厂、麻栗坪及金满、科登涧等大-中型矿床和矿点，并存在矿化分带。文章利用这些矿化脉体的流体包裹体和热液方解石的碳氧同位素组成资料，研究成矿流体与矿化分带的关系。结果表明，成矿流体主要属于NaCl-H2O成分体系，盐度ω(NaCleq)为2％～11％，形成温度为170～300℃，形成于1．8～3．8km深度内，这些相似性说明这类矿化的发生具有相似的流体性质和沉淀机制。热液方解石在δ^13C-δ^18O图解中呈近水平线展布的型式，指示流体源自地壳浅部的地下水系统，与海相灰岩等围岩作用形成了溶解碳以[HCO3^]-为主的成矿流体，流体与岩石的相互作用可能是成矿流体沉淀的主要机理。从西到东，流体包裹体的盐度-温度由高到低变化与矿化分带和逆冲推覆构造的根带→中带→锋带相配套，显示重力驱动流动可能是主要的流体流动机制。成矿流体在不同构造部位流动的通畅及流体．岩石系统的封闭-开放程度等流体流动性质与矿化发生的强度和规模有关，兰坪北部逆冲推覆构造中带的流体通畅地流动及沉淀时处于相对开放状态，有利于该区形成较大规模的浅成热液多金属矿化。