贵州五指山背斜纳雍枝铅锌矿地质特征及找矿前景分析

纳雍枝铅锌矿床位于五指山背斜北东部,是五指山矿集区的组成部分.区内铅锌矿体产于清虚洞组的白云岩中,自下而上共划分为9个矿体层,属沉积型铅锌矿床.矿石类型为碳酸盐岩型铅锌矿石.五指山地区位于紫云-垭都深大断裂的北东侧,南东侧有安顺-凯里深断裂,这些深断裂是纳雍枝矿床深部物质来源的前提,次一级的构造为矿床的形成提供了矿质流动的通道.五指山背斜Pb、Zn综合异常明显的部位,异常与区内构造较吻合,与矿床(点)展布方向一致.该矿床与典型密西西比河谷铅锌矿床具有较高的可比性.通过对纳雍枝铅锌矿床地质特征的总结及分析,认为五指山地区的找矿前景十分广阔.     

贵州纳雍枝铅锌矿床还原S的形成机制:NanoSIMS原位S同位素约束

位于黔西北地区的纳雍枝铅锌矿床,是目前报道的贵州省境内规模最大的铅锌矿床,已探明铅锌储量超过130万吨。纳雍枝铅锌矿床赋存于下寒武统清虚洞组和上震旦统灯影组碳酸盐岩中,受岩性和构造的双重控制,断层和背斜是主要控矿构造,铅锌成矿地质特征与MVT铅锌矿床较为相似。纳米离子探针(NanoSIMS)获得的纳雍枝铅锌矿床中黄铁矿和闪锌矿原位δ~(34)S分析数据表明,黄铁矿的δ~(34)S值变化范围在-16.6‰～+27.0‰之间,闪锌矿的δ~(34)S值范围为+11.8‰～+33.0‰,这与传统全矿物法获得的黄铁矿(δ~(34)S=+4.7‰～+18.1‰)和闪锌矿(δ~(34)S=+11.3‰～+25.22‰)的S同位素组成明显差异。根据矿物组合和晶体形态特征等,本文认为早期胶状、集合体状或交代残余黄铁矿(δ~(34)S=-16.6‰～-14.9‰)的还原S是由细菌引起的海相硫酸盐还原(BSR)产物,而晚期它形粒状黄铁矿和闪锌矿(δ~(34)S=+11.8‰～+33.0‰)的还原S是海相硫酸盐热化学还原作用(TSR)的产物。因此,纳雍枝铅锌矿床还原S的形成经历了BSR和TSR过程。综合以往地质地球化学研究资料,本文认为五指山地区铅锌矿床的空间分布受原地蒸发膏岩层的控制,BSR发生在成矿前,而TSR则是热流体加入后诱发的,矿床形成是构造-岩性-流体耦合作用的结果。     

纳雍枝铅锌矿床——贵州第一个大型铅锌矿床的发现和探明过程

纳雍枝铅锌矿床,位于贵州省中部普定县与织金县交界的五指山背斜南东翼,由北东向南西设置玉合、芦茅林、金坡和砂岩共4个矿权,2012-2015年4个矿权通过评审备案Pb+Zn资源量分别为35.29万t、37.79万t、44.49万t和53.29万t,总计170.86万t,是贵州省境内发现的第一个大型铅锌矿床,改写了贵州省没有大型铅锌矿床的历史。矿床从发现矿化线索到探明大体经历了3个阶段:第一,地表调查,发现矿化线索;第二,地质测量、面上矿点调查、工程验证发现断裂型小矿体;第三,转变找矿思路,探明了全隐伏、产出稳定、规模大的层控铅锌矿体。本文在总结纳雍枝大型铅锌矿床成矿背景和地质特征基础上,详细介绍了该矿床的发现过程、总结了找矿过程中的经验教训。     

贵州纳雍枝大型铅锌矿床成矿地质条件分析

纳雍枝铅锌矿床位于贵州中部五指山背斜南东翼,是贵州省境内发现的第一个大型铅锌矿床。本文利用矿床勘探和开发的最新地质资料,从成矿背景、构造、地层、岩性和岩相等方面分析了成矿地质条件。结果表明,五指山背斜控制了矿床的分布,区内与该背斜轴向近于平行的深断裂为成矿流体运移提供了有利通道,构造破碎带和地层层间破碎带为成矿提供了良好空间,赋矿地层下寒武统清虚洞组成矿元素高背景值为成矿提供了物质基础,地层中的白云岩和泥质白云岩为重要赋矿岩性,上部泥质白云岩(砂泥质层)+中部瘤状似瘤状白云岩或细-中晶白云岩+下上部泥质白云岩岩性组合是成矿的关键,有利矿化富集的地段是洼地微相、滩丘微相和过渡微相的急变带,沉积微相变化营造了良好的成矿环境。     

黔西北五指山地区铅锌矿床研究新进展:成矿带归属的启示

黔西北成矿区为川滇黔接壤矿集区的重要组成部分之一,但该地区以往未见有大型以上铅锌矿的报道。近些年来,贵州科技工作者在五指山地区取得重大的找矿突破,发现多个大中型铅锌矿床,提交铅锌金属资源量超过250万吨。为了使地质工作者更好地认识该矿田铅锌矿成矿作用,并为研究区及邻区找矿预测提供理论依据,本文系统总结五指山地区铅锌矿近些年的研究进展,并与川滇黔与湘西-黔东地区铅锌矿床从地质、地球化学以及成矿时代进行对比,尝试探讨五指山地区铅锌矿成矿带归属。地质和地球化学的综合研究表明,五指山地区的铅锌矿床的成矿物质主要来源于变质基底,水岩反应作用致使围岩贡献了少量的成矿物质,成矿流体具有多源性,主要为低温、中高盐度的卤水,可能混入少量的地层水,矿床成因类型属于MVT型铅锌矿床。年代学数据揭示,五指山地区铅锌矿成矿时代为(458.2±2.9) Ma,可能与武夷—云开陆内造山事件有关,暗示湘西—黔东地区同时代的铅锌成矿作用可能延伸到该地区。通过系统的地质和地球化学对比发现,五指山矿田内铅锌矿床与川滇黔接壤地区典型的铅锌矿床存在差异明显,而与湘西—黔东铅锌成矿带内典型矿床相似,故暂将其划分到该成矿带。     

贵州省铅锌矿矿床成因浅析

贵州铅锌矿主要分布于黔西和黔东地区铅锌矿成矿带上,前人认为属低温热液矿床[1、2]。而新发现的五指山铅锌矿[3],结合区内铅锌矿床特征分析认为,主要为喷流沉积矿床。在黔西地区主要产出于泥盆—石炭系碳酸盐岩地层的4个成矿亚带中,为燕山期产物;而沿五指山北东向展布的一系列铅锌矿、织金—纳雍成矿亚带和黔东铅锌成矿带,产出于震旦—寒武系碳酸盐岩地层,为加里东期产物。该认识对研究贵州省铅锌矿床和指导找矿具重要意义。     

贵州五指山地区铅锌矿矿床地质特征及其控矿因素

本文通过阐述贵州五指山铅锌矿田含矿地层岩石特征,构造地质特征,矿体产出形态和矿石特征以及地质找矿特征、控矿因素,认为震旦系、寒武系地层是五指山地区重要的铅锌含矿层位,运用地质、物探、化探、遥感等综合手段在该区找到了大中型铅锌矿床,对该区矿床地质特征和控矿规律进行了总结,并作了成矿预测。     

贵州五指山特大型铅锌矿床闪锌矿的Rb-Sr定年及其地质意义

贵州五指山铅锌矿床为近年新勘探出的特大型铅锌矿床,其成矿时代不明,成因类型及控矿因素争议较大。本文测定的该矿床那雍枝矿段闪锌矿的Rb-Sr等时线年龄,为458.2±2.9Ma (MSWD=1.07,n=5),初始⁸⁷Sr/⁸⁶Sr=0.713823±0.000010,表明矿床的成矿时代为中奥陶世晚期至晚奥陶世早期,晚于赋矿地层沉积时代。结合矿床地球化学及矿床地质特征,认为五指山铅锌矿床为典型的后生矿床,成因类型属密西西比河谷型(MVT)铅锌矿床。五指山铅锌矿床的形成与加里东构造运动紧密相关,与黔中隆起构造事件对应。基底断层构造及破碎带是成矿作用的内在控制因素,而加里东期华夏地块与扬子陆块之间的碰撞造山运动,即都匀运动及广西运动是五指山特大型铅锌矿床成矿作用的外因。     

贵州张维-五指山地区铅锌矿评价成果及意义

项目主攻矿种为铅、锌,主攻区域为张维—五指山地区铅锌矿化集中区,通过综合研究,采用地质、物探、钻探和坑道相结合的手段,重点对五指山地区那雍枝铅锌矿床和张维地区水东铅锌矿矿床进行解剖评价,估算了333+334铅锌金属资源量215.65万吨,其中333铅锌资源量52.03万吨,取得了很好的找矿效果;建立了五指山地区铅锌描述性综合信息找矿模型,经过成矿预测认为,五指山地区砂岩、落水岩、那润和喻家坝,张维地区的以则孔,果化地区的打麻厂和堰塘等,具有较好的找矿潜力,值得进一步开展地质工作;经过后期勘探,建设3个中型矿山,增加了当地居民和地方财税收入,在乌蒙山贫因地区具有经济和社会意义。     

贵州纳雍水东铅锌矿床地质特征及找矿远景

纳雍水东铅锌矿床共圈定7处铅锌矿体,矿体严格受断裂控制,呈透镜脉状产出。铅锌矿体平均厚度为1.50m,平均品位Zn9.06%,Pb1.05%。估算锌铅金属资源(332+333)总量分别为7.91万t和0.92万t,为小型矿床规模。通过在区内多年的勘查工作,并结合区内的地球化学异常特征,系统地分析了铅锌矿床的矿床地质特征、矿体形态以及矿石特征,并论述了矿床成因及Pb-Zn-Ag-Cd找矿前景。     

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