西藏革吉县尕尔穷铜金矿床地质特征及其成因意义

位于西藏阿里地区革吉县的尕尔穷铜金矿床是班公湖-怒江成矿带西段首个达到详查程度的大型铜金矿床。矿区发育三条断裂,其中F1和F2断层呈北东-南西向展布,F3断层为南北向展布。F1断裂产状复杂、延伸大于3000m,破碎带内发育的铜金矿体严格受其控制。目前,矿床主要由斑岩型钼(铜、金)矿体、接触带矽卡岩型铜金矿体、F1断裂破碎带内似IOCG型铁铜金矿体组成。不同矿体特征差别显著,斑岩型矿体主要产于石英闪长岩、花岗斑岩中,金属矿物以网脉状辉钼矿主,次为黄铜矿、磁铁矿、黄铁矿;矿物组合有磁铁矿+黄铁矿、黄铜矿+辉钼矿。矽卡岩型矿体主要产于石英闪长岩、花岗斑岩与碳酸盐岩接触带,呈层状、似层状,金属矿物主要为细脉-网脉状黄铜矿、斑铜矿、辉铜矿、铜蓝、自然铜、自然金、自然银,矿物组合为黄铜矿-磁铁矿-自然金、黄铜矿-斑铜矿-磁铁矿-自然金-银、黄铜矿-赤铁矿-自然金、辉钼矿、黄铜矿-自然金。破碎带内似IOCG型铁铜金矿体产于F1断裂破碎带,呈似层状,金属矿物以细脉-网脉状矿石和角砾状赤铁矿、磁铁矿、黄铜矿、斑铜矿、辉铜矿、铜蓝、自然金为主;矿物组合为黄铜矿-自然金、黄铜矿-斑铜矿-自然金-银矿、赤铁矿-磁铁矿-自然金、黄铜矿-自然金。根据矿床地质特征,综合前人研究资料,本文对矿床的成因进行了进一步探讨,认为尕尔穷铜金矿床是晚白垩世班怒洋关闭后南羌塘-三江复合板片与冈底斯-念青唐古拉板片之间弧-陆碰撞阶段形成的,具有与钾玄岩-高钾钙碱性闪长类岩体、陆-陆同碰撞钾玄岩-高钾钙碱性重熔型花岗斑岩有成因密切联系的构造-岩浆岩"三位一体"的成矿特征,即主矿体赋存于斑岩、矽卡岩、构造破碎带中形成的"斑岩-矽卡岩-似IOCG"型铜金矿床。     

西藏改则县白弄铜金矿床地质特征及意义

通过对白弄铜金矿床详细的地质构造背景、含矿岩石及产出特征等研究表明,测区班怒结合带内铜金矿不具有斑岩型矿床特征,其与班怒洋在早白垩世双向俯冲、碰撞形成的闪长岩、石英闪长岩关系密切,依此把测区内班怒结合带内的铜金矿床确定为白弄闪长岩型-矽卡岩型铜金矿床,进一步完善了班怒结合带西段铜金矿矿床的类型,为今后在班怒结合带内寻找铜金矿矿床提供了新的资料。     

西藏阿里地区尕尔穷铜金矿主要找矿标志特征——岩体蚀变、岩石高光谱、岩石地球化学测量

尕尔穷铜金矿床位于狮泉河晚燕山期结合带与冈底斯-念青唐古拉板片、南羌塘-三江复合板片缝合带西段构造单元的交汇处。尕尔穷铜金矿是班公湖-怒江成矿带西段第一个达到详查程度的矿床,其夕卡岩型矿体中金的资源量达到了中型规模。随着勘探进展在钻孔深部陆续发现花岗斑岩脉,与夕卡岩铜金矿体存在密切的成生关系。2011年的勘查工作又在断层破碎带中     

西藏班公湖-怒江成矿带上的碰撞后铜矿床

地处藏北高原的班公湖-怒江铜矿带是继藏东的玉龙斑岩铜矿带和藏南的冈底斯斑岩铜矿带之后,在青藏高原上发现的第三条铜矿带。与前两条斑岩铜矿带不同的是,班公湖-怒江铜矿带的铜矿床类型具有多样性,包括:1多龙、雄梅斑岩型铜金矿床;2尕尔穷-嘎拉勒斑岩-矽卡岩型铜金矿床;3拨拉扎斑岩型铜钼矿床;4舍索矽卡岩型铜(铅锌)多金属矿床。不同类型铜矿床的成矿时代集中在120~90 Ma之间,约30 Ma间隔内。文章通过沉积岩岩相学、火成岩岩石地球化学以及锆石U-Pb与辉钼矿Re-Os同位素年代学的综合研究,指出班公湖-怒江中特提斯洋盆的闭合时间为早白垩世初(140~130 Ma之间),班公湖-怒江成矿带上的铜矿床都形成于碰撞后造山环境。该成矿带与铜矿化有关的侵入岩主要为花岗闪长(斑)岩和石英闪长(玢)岩,在岩石地球化学上,富集大离子亲石元素(Rb、Th、U、Ba、K、Pb),亏损高场强元素(Nb、Ta、Ti),显示出俯冲组分对岩浆生成过程产生的重要影响,与碰撞后岩浆作用特征相吻合。除了班公湖-怒江铜矿带外,青藏高原上的另外两条斑岩铜矿带(即藏东的玉龙斑岩铜矿带和藏南的冈底斯斑岩铜矿带),也是形成于洋盆闭合之后的造山带碰撞后环境,因此,青藏高原可以说是地球上碰撞后铜矿床的天堂。     

西藏多龙矿集区尕尔勤岩石地球化学特征及构造环境

<正>多龙矿集区位于西藏自治区西北部的改则县境内,地处羌塘-三江复合板片南缘,班怒缝合带北侧,跨班公湖-怒江成矿带西段。近年班公湖-怒江成矿带西段的资源评价工作取得了突出的进展,相继发现多不杂、波龙超大型斑岩铜金矿床和外围的拿若铜金矿、荣那铜金矿、拿顿铜金矿、色拉铜金矿、地保那木岗铜矿、铁格龙金矿、尕尔勤铜金矿等矿床点,揭示出班公湖-怒江成矿带西段成矿条件优越和巨大的找矿     

黑龙江多宝山矿集区成矿规律与找矿方向

多宝山斑岩铜矿位于黑龙江省嫩江县境内,为我国北方重要的斑岩型铜矿床之一.在包括多宝山矿床在内的矿集区范围内资源丰富,有斑岩型铜(钼)矿床、矽卡岩型铁铜矿床以及热液型金矿床.在系统收集分析前人资料的基础上,查明矿集区成矿规律与找矿方向,认为复活了的基底构造对铜元素的迁移、富集和贫化起着重要的控制作用.矿集区北西段为矽卡岩...     

西藏班公湖-怒江成矿带西段富铁矿与铜（金）矿C、Si、O、S和Pb同位素特征及地质意义

本文在大量的野外地质调查与室内研究的基础上,对班公湖-怒江成矿带西段的4个典型矿床——材玛矽卡岩型铁矿床、弗野矽卡岩型铁矿床、尕尔穷矽卡岩型铜金矿床和多不杂斑岩型铜金矿床的C、Si、O、S和Pb同位素特征进行了研究.δ30Si、δ18O的研究结果表明,石英主要为岩浆热液成因,δ13C、δ18O同位素的研究结果表明,与成...     

藏北多龙斑岩铜金矿集区综合信息找矿模型研究

藏北多龙矿集区产出环境和成矿动力学背景在青藏高原斑岩铜矿中独具特色,目前已经发现了多龙、多不杂、拿若、荣那等超大型—大型斑岩铜(金)矿,其有效找矿模式亟待研究总结。典型矿床的综合信息找矿模型研究对于进一步开展矿体定位预测具有重要意义。研究认为多龙矿集区铜金矿体产于花岗闪长斑岩体内及岩体边部的黄铁绢英岩化和青磐岩化变质(长石)石英砂岩及火山岩中。自含矿斑岩体中心向外存在中心对称分布的3个蚀变带,依次为弱钾化带、绢英岩化带和黄铁矿化-角岩化带。根据地、物、化、遥异常套合特征,划分出"三带五田"。"三带"为呈北西向雁列状排列的拿若—色那—尕尔勤铜金矿带、多不杂—波龙—铁格隆南铜金钼矿带和地堡那木岗铜金矿带;"五田"为拿若—赛角—荣那矿田、尕尔勤矿田、地堡那木岗矿田、波龙—多不杂矿田和铁格隆南矿田,并分别厘定了各矿田的基本组成与矿床地质特征。通过地、物、化综合异常分析,建立了"四位一体"找矿模式。指出铁帽、孔雀石化和蚀变花岗闪长斑岩体为地表寻找斑岩铜矿的直接标志;低磁异常间接反映遭受蚀变的花岗闪长斑岩体成矿母岩;激电高极化异常直接反映斑岩型铜矿体两翼的黄铁矿化带,间接反映硫化物带包裹着铜矿体;Cu、Au元素高异常反映成矿元素的区域富集。以此为基础,对拿若、荣那矿区掩埋矿体运用了"四位一体"找矿模式,发现隐伏斑岩型铜矿床。     

西藏改则县波龙斑岩型铜金矿床地球化学特征及成因浅析

波龙铜金矿床是喜马拉雅特提斯成矿域班-怒成矿带西段产出的大型铜金矿床,是多龙铜金矿集区的重要组成部分,找矿潜力巨大。波龙矿区内的含矿斑岩体基本上全岩矿化,矿体呈不规则筒柱状产于早白垩世花岗闪长斑岩体中及其与下侏罗统曲色组砂岩的接触带内。目前控制矿体长度1200m,向深部延伸大于1000m(倾向200o),最大连续厚度为473.47m,未穿透矿体。矿体平面投影呈似椭圆状,面积约1.2km2。本文通过对波龙铜金矿床地质、矿床地球化学特征的研究,认为该矿床的形成与斑岩体侵位、岩浆期后成矿流体的演化有关,矿床类型属于斑岩型铜金矿。矿石构造为斑岩铜矿典型的细脉-浸染状构造。金属矿物以黄铜矿为主,次为黄铁矿、斑铜矿、辉钼矿、磁铁矿、镜铁矿等,非金属矿物有石英、长石、绢云母、黑云母、硬石膏等。通过硅酸盐分析,里特曼组合指数—戈蒂里图解表明波龙斑岩型铜金矿的花岗闪长斑岩属钙碱性系列,形成于岛弧环境;稀土元素地球化学特征反映以岩浆热液成矿作用为主。     

青藏高原两个斑岩-浅成低温热液矿床成矿亚系列及其"缺位找矿"之实践

斑岩_浅成低温热液型铜金矿床是西藏最新发现的组合矿床类型,其具有巨大的找矿潜力。笔者在西藏多龙矿集区铁格隆南铜金矿床、雄村矿集区主要矿体系统地质编录、综合研究的基础上,对其矿床地质背景、矿体形态产状、矿物组合、蚀变特征、成岩成矿年龄等进行了系统的总结,在前人研究的基础上,提出班怒成矿带与早白垩世岛弧型中_酸性火山岩_浅成岩组合有关的铜、金、银、铅锌矿床成矿亚系列,以及冈底斯成矿带与早侏罗世—晚侏罗世岛弧型中_酸性火山岩_浅成岩组合有关的铜、金、银、铅锌矿床成矿亚系列,是西藏最重要的寻找斑岩型_浅成低温热液型铜金矿的矿床成矿系列。依据"缺位找矿"理论,预测多龙矿集区尕尔勤、地堡那木岗、铁格隆山是浅成低温热液型铜金矿床的进一步勘查评价区,色那、拿顿角砾岩筒是寻找独立高硫化型浅成低温热液金矿床的重要靶区。铁格隆南浅成低温热液矿体叠加在斑岩型矿体之上,高硫化型浅成低温热液矿床浅部发育多孔状硅帽和明矾石_地开石_高岭石蚀变组合,金属矿物以硫砷铜矿_铜蓝_蓝辉铜矿_黝铜矿_黄铜矿_斑铜矿_黄铁矿等铜硫二元体系矿物组合为主,其中黄铁矿_黄铜矿_斑铜矿形成较早,矿床规模可突破1200万吨。雄村铜金矿集区发育低硫化型浅成低温热液多金属金矿体,矿体呈脉状,或在火山机构边缘构造中独立产出,或叠加于斑岩型铜金矿体之上产出,以绢云母化、叶蜡石化、伊利石化发育,闪锌矿、黝铜矿、磁黄铁矿_黄铁矿为主要金属矿物组合为特征,洞嘎、普钦木_哑达是低硫化型浅成低温热液矿床的勘查评价区,深部有找到斑岩型铜金矿的可能。上述2套矿床成矿系列亚系列都与燕山期斑岩铜金矿床的流体演化有关,具有特殊的蚀变矿物、金属矿物组合,寻找独立的浅成低温热液型金矿是下一步需要重视的找矿方向。     

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