炭质层控型银洞坡金矿的地质地球化学特征和矿床成因

炭质层控型金矿是一种很重要的新的金矿类型；银洞坡金矿产于中浅变质的含炭质火山－沉积岩系。矿体严格受炭质层控制，是炭质层控型金矿。矿床形成经历了初始沉积富集、加里东期变质叠加和中生代热液矿化就位的过程。中生代热液矿化分Ⅰ、Ⅱ、Ⅲ期，其温度分别为４５０－３００℃、，２５０－２００℃和２１０－１８０℃，Ⅰ期为变质热液；Ⅱ期为变质、岩浆、大气降水热液的三源混合热液。     

马庄山金矿地质特征及成矿地球化学条件

对马庄山金矿地质特征及地球化学条件研究表明，马庄山金矿的形成与古老变质基底、火山岩浆活动及马庄山一明水上叠火山岩盆地的火山岩、火山碎屑岩紧密相关，井受到晚古生代红河盆地闭合而派生的构造控制。其成矿温度在90～300℃之间，成矿流体为低盐度的弱酸性一弱碱性大气降水、海水和岩浆水的混合溶液。马庄山金矿成因为浅成中一低温次火山热液矿床。     

炭质层控型银洞坡金矿的地质地球化学特征和矿床成因

炭质层控型金矿是一种很重要的新的金矿类型。银洞坡金矿产于中浅变质的含炭质火山－沉积岩系。矿体严格受炭质层控制，是炭质层控型金矿。矿床形成经历了初始沉积富集、加里东期变质叠加和中生代热液矿化就位的过程。中生代热液矿化分Ⅰ、Ⅱ、Ⅲ期，其温度分别为４５０～３００℃、２５０～２００℃和２１０～１８０℃；Ⅰ期为变质热液；Ⅱ期为变质、岩浆、大气降水热液的三源混合热液；Ⅲ期是大气降水热液。其中Ⅱ期中温矿化最为重要。硫、碳、铅同位素表明成矿物质有多种来源，但可能以歪头山组为主。中生代华南与华北板块的碰撞造山作用导致矿床的最终形成。碰撞造山带的含炭岩系是银洞坡式金矿有利的找矿条件。     

八卦庙特大型金矿床热水沉积岩初探

八卦庙特大型金矿床位于凤太铅锌矿田北部,赋金地层形成于秦岭泥盆纪裂谷环境,其中发育有一套特殊沉积岩,包括(含)铁碳酸盐硅质岩、石英钠长石岩和(含)石英铁碳酸盐岩,主要呈层纹条带状产出。岩石学和地球化学研究表明,此套岩石属于热水沉积岩。作者认为八卦庙金矿初始形成于裂谷活动和热水沉积作用相对减弱期,属热水沉积-韧性剪切改造型金矿。此类型金矿与泥盆系铅锌矿共同构成热水沉积成矿系列,它具有广阔的找矿前景。     

八卦庙及外围金矿控矿因素与富集成矿规律研究

简述了凤太矿田中的典型构造蚀变岩型金矿床——八卦庙金矿的基本特征；初步分析了八卦庙金矿、丝毛岭金矿的地球化学特征，推测丝毛岭金矿点的成矿模式可能与八卦庙金矿床的成矿模式不同，或者是同一成矿系统中的不同成矿系列，而不同深度原生晕聚类分析谱系图显示，八卦庙金矿床随着深度的增加Au与亲岩浆（幔源岩浆）的元素相关性趋于密切，表明八卦庙金矿床的成矿有岩浆参与。重点研究了风太矿田中八卦庙及外围金矿的控矿因素——控矿构造特征、控矿地层及其岩性特征、矿化蚀变特征等，并以八卦庙金矿、柴蚂金矿为基础，总结归纳了八卦庙及外围金矿的富集成矿规律，进一步指明了八卦庙外围金矿的找矿方向及其找矿潜力。     

八卦庙超大型金矿床中铁白云石的特征兼论金矿成因

铁白云石是八卦庙超大型金矿床的主要脉石矿物，与金的矿化关系十分密切。根据其产状可分为浸染状、斑，支状和脉状等三种类型。它们在化学成分、碳氧同位素、包裹体特征等方面有许多相似之处，而在矿物共生组合、矿物形态特征上又有一定的差别。不同类型的铁白云石都是热液作用的产物，它们在金的运移、沉淀等方面起重要作用。铁白云石包裹体的温度ｔ／Ｃ为２４５－２９０，为八卦庙金矿是中温热液矿床提供了证据。     

云南岔河铜矿成矿时代与成因

早元古界岔河变质岩中铜矿石黄铜矿的Ｐｂ－Ｐｂ等时线年龄为９５１±３６Ｍａ，属于晋宁运动早期的成矿作用。矿石稀土分配模式与围岩相似，二者均以富轻稀土为特征，Ｅｕ轻微亏损，矿床成因与含铜变质岩系有关。黄铜矿的δ３４Ｓ值分布范围为－１２．４７‰－－５．３２‰，平均值为－８．９３‰。含矿岩系形成于近海开放体系中。微量元素研究表明，区域地层Ｃｕ、Ｍｏ、Ｓ的丰度较高，比泰勒的地壳丰度值高３－１０倍。Ｃｕ在矿化过程中，变质作用和构造控制有重要意义，地层中的成矿元素在有利的构造部位沉淀，形成浸染状矿化和石英硫化物脉。该矿床属于火山－沉积变质矿床。     

陕西凤县八卦庙特大型金矿的成因研究

陕西凤县八卦庙金矿是一个近期探明的特大型金矿，通过对八卦庙金矿全面深入地研究，发现它是一种多成因复成矿床，早期为剪茂成矿，中期为岩浆热液蚀变成矿，晚期在浅部为风化煤滤富集成矿，剪切作用形成金矿是主体。     

八卦庙金矿控矿构造研究

陕西风县八卦庙金矿是近期探明的特大型金矿。经研究发现它的成因与脆韧性剪切和岩浆热液蚀变有关。在八卦庙矿区至二里河铅锌矿一带发育了一条脆韧性剪切带，它控制了金矿体在走向（NWW－SEE）上的分布。金矿主要产在剪切带的脆韧性剪切条带和后期脆性剪切形成的碎裂告内；NE向在行小型断裂及其NE向节理控制了后期岩浆热液蚀变形成的矿脉的分布。在北矿带这些矿脉叠加在脆韧性剪切形成的NWW向展布的金矿体之上，形成富矿带。     

八卦庙金矿床中含金石英脉的地球化学特征及意义

八卦庙金矿床是分布于秦岭造山带中的一种中高温碳酸盐型热液金矿床。石英是其主要的脉石矿物之一，与金矿化密切相关。根据含金石英脉的产状可将其分为三种类型：①顺层石英脉；②含铁白云石石英脉；③ＮＥ向节理石英脉。它们在微量元素和稀土元素的组成特征上有一定的差异，分别形成于金的不同成矿阶段，是金在成矿作用过程中演化的产物。同时，为八卦庙金矿的成矿提供了条件。石英中包裹体测温结果为八卦庙金矿床的中温成因提供了证据     

The terrestrial fauna of the Late Triassic Pant-y-ffynnon Quarry fissures,South Wales,UK and a new species of Clevosaurus (Lepidosauria: Rhynchocephalia)

Pant-y-ffynnon Quarry in South Wales yielded a rich cache of fossils in the early 1950s, including articulated specimens of new species (the small sauropodomorph dinosaur Pantydraco caducus and the crocodylomorph Terrestrisuchus gracilis), but no substantial study of the wider fauna of the Pant-y-ffynnon fissure systems has been published. Here, our overview of existing specimens, a few described but mostly undescribed, as well as freshly processed material, provides a comprehensive picture of the Pant-y-ffynnon palaeo-island of the Late Triassic. This was an island with a relatively impoverished fauna dominated by small clevosaurs (rhynchocephalians), including a new species, Clevosaurus cambrica, described here from a partially articulated specimen and isolated bones. The new species has a dental morphology that is intermediate between the Late Triassic Clevosaurus hudsoni, from Cromhall Quarry to the east, and the younger C. convallis from Pant Quarry to the west, suggesting adaptive radiation of clevosaurs in the palaeo-archipelago. The larger reptiles on the palaeo-island do not exceed 1.5?m in length, including a small carnivorous crocodylomorph, Terrestrisuchus, and a possible example of insular dwarfism in the basal dinosaur Pantydraco.     

The effect of water on accessory phase solubility in subaluminous and peralkaline granitic melts

The solubilities of columbite, tantalite, wolframite, rutile, zircon and hafnon were determined as a function of the water contents in peralkaline and subaluminous granite melts. All experiments were conducted at 1035 °C and 2 kbar and the water contents of the melts ranged from nominally dry to approximately 6 wt.% H₂O. Accessory phase solubilities are not affected by the water content of the peralkaline melt. By contrast, solubilities are affected by the water content of the subaluminous melt, where the solubilities of all the accessory phases examined increase with the water content of the melt, up to 2 wt.% H₂O. At higher water contents, solubilities are nearly constant. It can be concluded that water is not an important control of accessory phase solubility, although the water content will affect diffusivities of components in the melt, thus whether or not accessory phases will be present as restite material. The solubility behaviour in the subaluminous and peralkaline melts supports previous spectroscopic studies, which have observed differences in the coordination of high field strength elements in dry vs. wet subaluminous granitic glasses, but not for peralkaline granitic glasses. Lastly, the fact that wolframite solubility increases with increasing water content in the subaluminous melt suggests that tungsten dissolved as a hexavalent species.     

Quaternary stresses revealed by calcite twinning inversion: insights from observations in the Savonnières underground quarry (eastern France)

Calcite samples were extracted both from the rock matrix and the superficial coating of a karstified fault plane of an underground quarry, located in the eastern border of the Paris basin. The karstification is dated as Quaternary. Analysis of mechanical calcite twinning reveals that only the calcite matrix has also undergone a compression trending WNW that can be attributed to the Mio-Pliocene alpine collision. Both coating and matrix have undergone a strike-slip regime with σ₁ roughly trending north–south, that could correspond to the regional present-day state of stress, a strike-slip compression rather trending NNW, modified by local phenomena. To cite this article: M. Rocher et al., C. R. Geoscience 335 (2003).     

HYDROGEOLOGY

正20141756 Chen Ruige(Mathematical College,China University of Geosciences,Beijing100083,China);Zhou Xun Numerical Simulation of Groundwater Level Fluctuation in a Coastal Confined Aquifer with Sloping Initial Groundwater Level Induced by the Tide(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(7),2013,p.1099-1104,6 illus.,16 refs.) Key words:confined water,groundwater level     

METAMORPHIC PETROLOGY

正20141408 Cai Jia(Institute of Geology,Chinese Academy of Geological Sciences,Beijing100037,China);Liu Fulai Petrogenesis and Metamorphic P-T Conditions of Garnet-Spinel-Biotitebearing Paragneiss in Danangou Area,Daqingshan-Wulashan Metamorphic Complex Belt(Acta Petrologica Sinica,ISSN1000-0569,CN11-1922/P,29(7),     

SERIALS

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GEOPHYSICAL EXPLORATION

正20142386An Guoying(China Aero Geophysical Survey and Remote Sensing Center for Land and Resources,Beijing 100083,China)Application of Satellite Remote Sensing in Regional Hydrogeological Investigation:Taking Cenozoic Strata in Wenquan Sheet(1∶250 000)of Karakoram Range as an Example(Geosci-     

QUATERNARY GEOLOGY & GEOMORPHOLOGY

正20141016An Chengbang(Key Laboratory of Western China’s Environmental Systems,Ministry of Education,Lanzhou University,Lanzhou 730000,China);Zhao Yongtao Lake Records during the Last Glacial Maximum from Xinjiang,NW China and Their Climatic Impli-     

PETROLEUM GEOLOGY

正20141538 Cao Qing(School of Earth Sciences and Engineering,Xi’an Petroleum University,Xi’an 710065,China);Zhao Jingzhou Characteristics and Significance of Fluid Inclusions from Majiagou Formation,Yichuan Huangling Area,Ordos Basin(Advances in Earth Science,ISSN1001-8166,CN62-1091/P,28(7),2013,p.819-828,7 illus.,3 tables,43 refs.)     

GEOCHEMISTRY

正20142002 Wei Hualing(Institute of Geophysical and Geochemical Exploration,Chinese Academy of Geological Sciences,Langfang065000,China);Zhou Guohua Element Content and Mineral Compositions in Different Sizes of Soil in Tongling Area,Anhui Province(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(11),2013,p.1861