新城金矿稳定同位素地球化学特征及成矿物质的来源

新城金矿是胶东金矿集区招远—莱州成矿带的一个"焦家式"蚀变型金矿床。本文主要通过C、H、O、S、Pb同位素研究,对新城金矿成矿流体、物质来源和成矿作用进行探讨和研究。新城金矿矿石中δD值范围为-116‰~-91‰,δ18O水值范围为3.8‰~7.2‰,表明成矿流体早期来源于岩浆水,成矿晚期混入大气降水。矿石硫化物、郭家岭花岗闪长岩、玲珑花岗岩和胶东群δ34S平均值分为7.9‰、6.5‰、8.5‰和6.2‰,认为矿石硫具有对矿区地层及岩浆岩硫的继承性。硫化物矿石206Pb/204Pb=17.115~17.414,207Pb/204Pb=15.460~15.577,208Pb/204Pb=37.912~38.196,显示铅具有壳幔混合来源的特征。碳、氢、氧、硫、铅同位素反映新城金矿成矿物质和流体主要来源于深部岩浆。     

新城金矿稳定同位素地球化学特征及成矿物质来源探讨

新城金矿是胶东金矿集区招远—莱州成矿带的一个"焦家式"蚀变型金矿床。本文主要通过C、H、O、S、Pb同位素研究,对新城金矿成矿流体、物质来源和成矿作用进行探讨和研究。新城金矿矿石中δD值范围为-116‰~-91‰,δ18O水值范围为3.8‰~7.2‰,表明成矿流体早期来源于岩浆水,成矿晚期混入大气降水。矿石硫化物、郭家岭花岗闪长岩、玲珑花岗岩和胶东群δ34S平均值分为7.9‰、6.5‰、8.5‰和6.2‰,认为矿石硫具有对矿区地层及岩浆岩硫的继承性。硫化物矿石206Pb/204Pb=17.115~17.414,207Pb/204Pb=15.460~15.577,208Pb/204Pb=37.912~38.196,显示铅具有壳幔混合来源的特征。碳、氢、氧、硫、铅同位素反映新城金矿成矿物质和流体主要来源于深部岩浆。     

贵州独山巴年锑矿床硫、铅同位素特征及其对成矿物质来源的指示

贵州独山巴年锑矿床是华南锑矿带代表性锑矿床之一。矿体赋存于中泥盆统独山组地层之中。本文对该矿床辉锑矿的硫、铅同位素组成进行了系统分析。结果表明,辉锑矿的δ34S值变化范围为-5.4‰～-1.2‰,平均-4.2‰,计算获得成矿流体中总硫的δ34SΣS=0.1‰,显示岩浆来源硫的同位素特征。辉锑矿铅同位素组成变化范围较窄:206Pb/204Pb为18.561～19.156,平均18.813;207Pb/204Pb为15.703～15.769,平均15.734;208Pb/204Pb为38.573～39.207,平均38.906。绝大多数样品中矿石铅为正常铅,具有华南区域性铅同位素组成特征。我们认为巴年锑矿床成矿金属元素锑除主要来源于赋矿围岩泥盆系外,基底地层也可能提供了部分成矿物质。     

湖南香花岭锡多金属矿床同位素地球化学研究

笔者对湖南香花岭锡多金属矿床成矿期不同的矿物组合进行矿物包裹体温度和硫、铅同位素测定,获得了锡石-硫化物阶段平均-温度为350℃,硫化物阶段平均均-温度为250℃.锡石-硫化物中黄铁矿的δ34为-1.O‰～+5.4‰;闪锌矿的δ34S为+0.8‰-+5.8‰;磁黄铁矿的δ34S为+1.5‰～5.2‰;方铅矿的δ34S为-1.0‰+3.6‰,具有变化范围小,组成稳定的特点.方铅矿的206Pb/204Pb值为17.785～19.341,207Pb/204Pb值为15.416～16.452,208Pb/204Pb值为38.357～42.579.硫同位素指示硫来源于岩浆,铅同位素指示是多来源.     

广东大宝山多金属矿床成矿物质来源同位素证据

笔者对大宝山多金属矿床矿石和脉石矿物进行铅、硫、氢和氧同位素组成测定,获得硫化物的206Pb/204Pb值为17.930～18.785;207Pb/204Pb值为15.491～15.772;208Pb/204Pb值为37.990～40.990,并组成良好的线性关系。泥盆系地层中黄铁矿的δ34S为-22.5‰～+17.9‰,矿床硫化物的δ34S为-2.4‰～+4.6‰。黄铁矿、闪锌矿和方铅矿共生矿物对,具有δ34Spy>δ34Ssp>δ34Sgn,用磁黄铁矿的硫同位素组成估算出δ34S∑S为2‰±3‰。硫化物包裹体的氢同位素在-101‰～-123‰之间,与硫化物共生石英的氧同位素为+9.3‰～+17.9‰,换算成水的氧同位素为+0.3‰～+3.9‰,表明成矿热液来源较为复杂。     

凡口铅锌矿床同位素地球化学证据

对凡口铅锌矿床不同成矿阶段进行矿物包裹体温度、硫和铅同位素测定，获得成矿第Ⅰ阶段温度为300±50℃，第Ⅱ、Ⅲ阶段温度为250±50℃；并获得矿床硫化物的S同位素组成为2.1‰～26.5‰，具有δ34SPy＞δ34SSp＞δ34SGn；第Ⅰ阶段硫化物的硫同位素组成随赋存层位由老到新硫同位素有逐渐减小趋势；第Ⅱ阶段硫化物的δ34S为14.3‰～23.8‰；第Ⅲ阶段硫化物的δ34S为5.7％~15.7‰，具有从早阶段至晚阶段硫同位素组成变化范围从大至小的减小趋势。分析获得68件铅同位素数据，其中硫化物的206Pb/204Pb比值为18.023～18.847；207Pb/204Pb比值为15.700～15.820；208Pb/204Pb比值为38.056～39.796。灰岩全岩的206Pb/204Pb比值为18.230～18.860；207Pb/204Pb比值为15.640～16.000；208Pb/204Pb比值为38.714～39.960。辉绿岩的206Pb/204Pb比值为18.570～18.650；207Pb/204Pb比值为15.260～15.620；208Pb/204Pb比值为38.650～38.960。第Ⅰ阶段δ34OH2O为13.3‰~13.1‰，δD为－50.2‰～－61.5‰；第Ⅱ阶段δ18OH2O为－2.4‰～＋10.8‰，δD为－50.2‰～－63.2‰；第Ⅲ阶段δ18OH2O为－4.9‰～－14.3‰，δD为－59.0‰～－61.0‰。     

黔西北赫章天桥铅锌矿床成矿物质来源:S、Pb同位素和REE制约

赫章县天桥铅锌矿床位于扬子准地台西南缘的黔西北铅锌成矿区中部,是本区已发现的96处中、小型矿(床)点的典型代表。天桥铅锌矿床由三个矿体群组成,其金属资源量(Pb+Zn)超过0.2Mt。本文报道了该矿床矿石硫化物的硫和铅同位素组成及其稀土元素组成特征。矿石硫化物δ34SV-CDT值主要集中在8.4‰～14.4‰之间,总体具有δ34Spyδ34Sspδ34Sga特征,表明成矿流体中硫已达到平衡。该矿床成矿流体中δ34S∑S值与不同时代地层中海相硫酸盐δ34S值(15‰)相近,表明成矿流体中硫来源于不同时代地层,为不同时代地层海相硫酸盐热化学还原(TSR)的产物。铅同位素组成相当均一,n(208Pb)/n(204Pb)值为38.875～39.057(平均38.945),n(207Pb)/n(204Pb)值为15.708～15.763(平均15.728),n(206Pb)/n(204Pb)值范围为18.481～18.544(平均18.516),与碳酸盐地层相近,在n(208Pb)/n(204Pb)—n(206Pb)/n(204Pb)和n(207Pb)/n(204Pb)—n(206Pb)/n(204Pb)图,落入碳酸盐地层范围内,表明铅来源于与矿物铅同位素组成相近的各时代碳酸盐地层。硫化物样品具有低ΣREE(3×10-6)和负的Eu异常(0.13～0.88)特征。在稀土元素球粒陨石标准化配分模式图上,全部样品具有相似特征,且与地层中的黄铁矿(下石炭统大塘组C1d)、地层白云岩及蚀变围岩相比,具有一致的稀土配分模式和Eu负异常特征,表明成矿流体来源围岩及下伏碳酸盐地层。综合S、Pb同位素和REE地球化学特征认为该矿床成矿物质和成矿流体具有多来源特征,各时代地层均不同程度地为成矿提供物质和流体。     

西藏加多捕勒铁铜矿床硫、铅同位素组成及成矿物质来源

加多捕勒铁铜矿床位于念青唐古拉成矿带西段。综合研究围岩、岩体与矿石的硫、铅同位素组成,发现其矿石硫化物的δ~(34)S值变化范围为-2.1‰～6.2‰,δ~(34)S_(ΣS)值为2.16‰,总体具有岩浆硫的特征。矿石硫化物的δ~(34)S值与石英闪长岩、板岩中硫化物的δ~(34)S值相近,表明矿石的硫源可能部分由板岩与石英闪长岩提供。矿石铅同位素组成比较均一,~(206)Pb/~(204)Pb、~(207)Pb/~(204)Pb和~(208)Pb/~(204)Pb的变化范围分别为18.27～18.842、15.653～15.899和38.793～39.703,与冈底斯成矿带北亚带矿床矿石硫化物的铅同位素组成相近,具有上地壳铅源的特征。矿石铅同位素组成与黑云母二长花岗岩、大理岩的铅同位素组成一致,显示铅可能主要来源于黑云母二长花岗岩和大理岩。综合分析表明,加多捕勒铁铜矿床硫、铅同位素的研究显示其成矿物质可能主要来源于黑云母二长花岗岩,部分来源于中二叠统下拉组岩石,少量由石英闪长岩提供,它们为深入研究该矿床的成矿模式提供了资料。     

新疆西南天山霍什布拉克铅锌矿床地质、地球化学及成因

霍什布拉克铅锌矿是西南天山地区的典型矿床。矿床以晚古生代碳酸盐岩-碎屑岩为容矿岩石,矿体呈板状、层状、似层状产于上泥盆统坦盖塔尔组上岩性段灰岩层位中,宏观及微观现象均显示后生成矿特点,围岩蚀变较弱。矿石矿物主要为方铅矿、闪锌矿,少量黄铜矿,脉石矿物以黄铁矿、方解石、白云石、石英为主。黄铁矿Co/Ni比值<1,指示其成因与盆地流体相关,闪锌矿浅色、贫铁〔w(Fe) 0.652%～1.797%〕,反映中低温成矿。矿石中热液方解石、白云石δ13CV-PDB＝-1.9‰～2.6‰,δ18OV-SMOW＝22.41‰～24.67‰,流体包裹体δDV-SMOW＝-102‰ ～ -77‰,平衡流体δ18OH2O V-SMOW＝9.97‰～13.35‰,反映成矿流体主要为盆地中的封存水,而其中的碳主要来源于围岩碳酸盐岩。矿石中硫化物δ34S值多数集中于16‰～24‰,指示硫来源于海相硫酸盐的热化学还原。矿石铅同位素206Pb／204Pb、207Pb／204Pb、208Pb／204Pb变化范围分别为17.847～18.173、15.586～15.873、37.997～38.905,与围岩碳酸盐岩地层具有可比性,而明显不同于矿床附近二叠纪侵入岩体,指示围岩提供了成矿物质。铅同位素组成和相关参数指示成矿物质主要来源于上地壳。综合地质、地球化学特征,作者认为霍什布拉克铅锌矿床是造山期逆冲推覆作用使盆地流体大规模活化、运移形成的MVT型矿床。     

扬子陆块北缘马元铅锌矿床成矿物质来源探讨: 来自C、O、H、S、Pb、Sr同位素地球化学的证据

呈层状、似层状产于震旦系灯影组角砾状白云岩层间构造带中的马元铅锌矿床是近年来在扬子陆块北缘铅锌找矿的新突破。文章通过碳、氧、氢、硫、铅和锶同位素地球化学特征研究,探讨了成矿流体和成矿金属来源。研究结果表明:矿石中热液脉石矿物的δ13CPDB为-4.24‰~0.93‰,δ18OSMOW为15.92‰~23.24‰,表明成矿流体中的CO2为震旦系碳酸盐岩的溶解成因。矿石中硫化物的δ34S变化于12.94‰~19.4‰之间;硫酸盐矿物的δ34S为32.2‰~33.48‰,表明还原硫主要来自地层中海相硫酸盐的还原。矿石硫化物的铅同位素组成均一,206Pb/204Pb、207Pb/204Pb和208Pb/204Pb分别为17.62~18.02、15.49~15.63和37.57~38.35,成矿金属可能主要来源于震旦系—志留系。脉石矿物石英流体包裹体的δDFI为-92‰和-113‰,如果取成矿温度200℃,根据δ18O石英值计算的相应流体包裹体的δ18O水为6.03‰~12.73‰,推测成矿流体可能起源于大气降水为主的盆地卤水,或为其他来源的流体与有机质反应形成。成矿流体87Sr/86Sr为0.70967~0.71146,高于赋矿围岩震旦系灯影组白云岩锶同位素比值(0.70890~0.70945),表明成矿流体流经了古生代地层(及基底),并与其中具有高锶同位素比值的碎屑岩、页岩和泥岩等进行了水岩反应及同位素交换。     

Définition d'une limite multicritère ; stratigraphie du passage Campanien–Maastrichtien du site géologique de Tercis (Landes,SW France)Definition of a multi-criteria boundary; stratigraphy of the Campanian–Maastrichtian interval of the geological site at Tercis (Landes,SW France)

Lithostratigraphy, physicochemical stratigraphy, biostratigraphy, and geochronology of the 77–70 Ma old series bracketing the Campanian–Maastrichtian boundary have been investigated by 70 experts. For the first time, direct relationships between macro- and microfossils have been established, as well as direct and indirect relationships between chemo-physical and biostratigraphical tools. A combination of criteria for selecting the boundary level, duration estimates, uncertainties on durations and on the location of biohorizons have been considered; new chronostratigraphic units are proposed. The geological site at Tercis is accepted by the Commission on Stratigraphy as the international reference for the stratigraphy of the studied interval. To cite this article: G.S. Odin, C. R. Geoscience 334 (2002) 409–414.     

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).     

NONMETALS DEPOSITS

正20141520 Bo Ying(Key Laboratory of Metallogeny and Mineral Assessment,MLR,Beijing 100037,China);Liu Chenglin Saline Spring Hydrochemical Characteristics and Indicators for Potassium Exploration in Southwestern and Northern Tarim Basin,Xinjiang(Acta Geoscientica Sinica,ISSN1006-3021,CN11-3474/P,34(5),2013,p.594-602,5 illus.,3 tables,28 refs.)     

MATHEMATICAL GEOLOGY

正20141243Chen Ge(Hangzhou Research Institute of Petroleum Geology,PetroChina,Hangzhou 310023,China);Si Chunsong Study on Sedimentary Numerical Simulation Method of Fan Delta Sand Body(Journal of Geology,     

PROSPECTING EXPLORATION

正20142599Chen Sanming(Guangxi Key Laboratory of Concealed Deposits Exploration,Guilin University of Technology,Guilin541004,China);He Yuzhou Block Model and Reserves Estimation of Panzhihua Iron Deposit Based on 3D Geological Modeling(Journal of Guilin University of Technology,ISSN1674-9057,CN45-1375/N,33(4),2013,p.610-615,9illus.,1table,15refs.)     

STRUCTURAL GEOLOGY

正20140594 Bai Daoyuan(Hunan Institute of Geology Survey,Changsha 410016,China);Zhong Xiang Faults in the Jingzhou Basin and Their Tectonic Settings(Geotectonica et Metallogenia,ISSN1001-1552,CN44-1595/P,37(2),2013,p.173-183,6illus.,59refs.)Key words:basin evolution,tectonic setting,South China In the Upper Paleozoic and Jurassic se-     

STRUCTURAL GEOLOGY

正20141912Cao Hui(State Key Laboratory for Continental Tectonics and Dynamics,Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037,China)Gravitational Collapse and Folding during Orogenesis:A Comparative Study of FIA Trends and Fold Axial Plane Traces(Geology in China,ISSN1000-3657,CN11-1167/P,40(6),2013,p.1818-1828,9illus.,35refs.,with     

PALEOZOOLOGY

正20141609 Chen Guiying(College of Earth Sciences,Guilin University of Technology,Guilin 541004,China);Han Nairen New Materials of Stylophora from the Upper Cambrian of the Jingxi Area,Guangxi,South China(Acta Palaeontologica Sinica,ISSN0001-6616,CN32-1188Q,52(3),2013,p.288-293,2 illus.,12 refs.)Key words:Stylophora,Guangxi     

GEOPHYSICS

正20140634 Cao Lingmin(Key Laboratory of Marine Geology and Environment,Institute of Oceanology,Chinese Academy of Sciences,Qingdao 266071,China);Xu Yi Finite Difference Tomography of the Crustal Velocity Structure in Tengchong,Yunnan Province(Chinese Journal of Geophysics,ISSN0001-5733,CN11-2074/P,56(4),2013,p.1159-1167,6illus.,35refs.,with English abstract)