青海省治多县查涌铜多金属矿床成矿年代学研究

三江"成矿带为我国重要的多金属成矿带,带内中北段玉树多彩矿集区发育多种类型的铜多金属矿床,资源潜力巨大,但成矿年龄不详,严重制约了对矿床和区域成矿规律的理解。因此,本次工作选取矿集区西北部查涌铜多金属矿床为研究对象,在详细地质踏勘的基础上,对其成矿年代进行了系统研究,以期填补该地区此类型矿床成矿年龄的空白。研究表明,查涌铜多金属矿床分别发育Cu-Mo矿体和Pb-Zn矿体,Cu-Mo矿体赋存在变质粉砂岩内,形成于石英硫化物阶段。角岩化砂岩中黑云母Mg-(Al^Ⅵ+Fe^3++Ti)-(Fe^2++Mn)的投图具镁质黑云母特征,Al2O3/Ti O2值介于6.359~10.087之间,Fe^2+/(Fe^2++Mg)值均一,为热液成因,且未受后期流体改造,40Ar-^39Ar同位素定年获得黑云母封闭年龄为129.59±1.58 Ma。穿切黄铜矿的辉钼矿Re含量为0.864×10^-6~9.624×10^-6,具壳源属性,其Re-Os同位素等时线年龄为124.75±0.86 Ma。热液黑云母与较晚的辉钼矿年龄相近,应为同期岩浆热液事件的产物。本次研究精确厘定了"三江"带中北段内一例典型的与岩浆热液成矿作用相关铜多金属矿床的成矿年龄,揭示出早白垩世的一期成矿事件,为"三江"成矿带的成矿规律总结和勘查找矿指明了新的方向。     

东天山硫磺山铜多金属矿床成岩成矿作用同位素地质年代学

前人根据矿体的产出受碳酸盐岩层位控制和Pb同位素模式年龄资料,多认为硫磺山铜多金属矿床为层控型铜铅锌多金属矿床,其形成时代为奥陶纪.基于矿区石英斑岩体见矿化和矿化蚀变,矿体与围岩呈渐变关系等特点,笔者主张该矿床属斑岩型铜铅锌多金属矿床.年代学研究表明,含矿石英脉Rb-Sr等时线年龄(346±30 Ma)与石英斑岩的锆石U-Pb年龄(340~360 Ma)在测定误差范围内一致,表明成岩与成矿作用均发生在早石炭世-晚泥盆世,成矿作用无论从空间上和时间上都与石英斑岩有关.     

兰坪盆地三类主要铜银多金属矿床的稳定同位素地球化学

通过对兰坪盆地内三种主要成因类型（沉积-热液改造型、热水沉积-热液改造型和热液脉型）的铜银多金属矿床硫、碳、氢、氧同位素的研究,揭示了成矿作用过程的某些重要信息：矿石中的硫主要来自细菌还原的海水硫酸盐,但在沉积-热液改造型矿床中可能还有部分有机生物硫和深源火山硫的贡献;碳主要来自不同比值水/岩反应体系中碳酸盐岩地层的溶解结果,但在沉积-热液改造型矿床中还可能有深部地幔去气作用带来的CO2.成矿流体系以大气降水为主要补给源的盆地建造水,盆地建造水的运移成矿过程中可能伴有较为明显的蒸发作用.     

云南兰坪盆地西缘脉状铜多金属矿床硫、铅同位素组成及成矿示踪

云南兰坪盆地西缘脉状铜多金属矿床主要赋存于由砂岩、粉砂岩和页岩组成的碎屑岩建造中.为了查明兰坪盆地西缘脉状铜多金属矿床成矿物质来源,对盆地西缘四个典型脉状铜多金属矿床(科登涧、连城、金满和水泄)的硫、铅同位素的组成进行了分析和对比研究.结果表明,这些矿床的铅同位素组成总体变化较小,且大部分落在盆地沉积地层铅范围内,金满、连城铜矿床可能有部分深源铅的加入.硫同位素特征表明,兰坪盆地西缘脉状铜多金属矿床的硫主要来源于地层硫酸盐的还原作用,其中金满铜矿床和连城铜钼多金属矿床可能有深源硫的混入.各矿床硫同位素不同的特点,除反映各矿床源区硫同位素组成的差异外,可能还与各矿床成矿时不同的物理化学条件(温度、氧逸度、pH 值和离子强度等)差异有关     

北祁连南缘右行韧性走滑剪切带的同位素年代学及其地质意义

北祁连南缘右行韧性走滑剪切带位于祁连地块与北祁连俯冲碰撞杂岩带边界 ,长约 80 0km ,走向NWW SEE ,面理向北陡倾 ,中西部宽 5～ 6km ,东部由四条呈帚状撒开的强应变带组成。构造指向及向南东低角度倾伏的拉伸线理揭示出韧性剪切带的右行走滑和转换挤压性质。TIMS法测定的单颗粒锆石U Pb上交点年龄为 96 5～ 95 6Ma ,代表韧性剪切带原岩———基底变质岩的变质时代。糜棱岩中钾长石、黑云母单矿物40 Ar/ 3 9Ar同位素测年结果及与地层和岩浆活动的关系表明韧性剪切带形成于 4 4 0～ 380Ma。北祁连南缘右行韧性走滑剪切带是在祁连加里东造山带形成过程中 ,祁连地块与阿拉善地块间斜向碰撞诱发大规模转换挤压作用的产物。     

甘肃南金山金矿床的40Ar-39Ar同位素年龄及其地质意义

南金山金矿是我国西北地区最重要的金矿床之一,矿床产于下石炭统白山组浅变质海相火山碎屑岩中.本文通过对金矿床中的蚀变绢云母进行了40Ar-39Ar同位素年龄测定,获得了两组数据,分别为250.6±2.8 Ma和232.7±4.1Ma,说明南金山金矿的形成经历了两期成矿作用.     

滇西北兰坪盆地金满-连城脉状Cu多金属矿床Cu-S同位素特征及其指示意义

兰坪盆地西缘发育一系列脉状Cu多金属矿床,成矿独具特色,它们的成矿流体普遍存在大量富CO₂流体包裹体,在整个兰坪盆地罕见,显著区别于世界上已知的各类贱金属矿床。本研究测定了兰坪盆地西缘两个代表性脉状Cu矿床(金满Cu矿床和连城Cu-Mo矿床)主成矿阶段黄铜矿和黝铜矿的Cu-S同位素组成,探讨其成矿物质来源和成矿机制。结果表明,金满Cu矿床黄铜矿的δ⁶⁵Cu值变化较大(-3.62‰~0.48‰),δ³⁴S值为-4.0‰~12.1‰,可能与多期流体活动、成矿物质多来源有关,成矿主要与深部岩浆活动有关,成矿晚期有地层物质的加入。连城Cu-Mo矿床主成矿期黄铜矿δ⁶⁵Cu值为-0.31‰~2.12‰,δ³⁴S值为-3.6‰~1.4‰,暗示成矿与深部岩浆作用有关。     

紫金山铜金矿同位素年代学及其地质意义

紫金山铜金矿同位素年代学及其地质意义周肃，陈好寿（宜昌地质矿产研究所，湖北宜昌４４３００３）（浙江大学地球科学系，杭州３１００２７）关键词铜金矿，同位素年代学，成岩成矿时序紫金山铜金矿床是我国近年来发现的首例石英－明矾石型浅成低温热液矿床［１］。本文...     

南疆斯如依迭尔铜多金属矿床的地质特征及其成矿时代

近些年发现的斯如依迭尔铜多金属矿床有望改变南疆无大—中型铜矿的局面,对其研究意义显著。该矿床已圈定铜多金属矿体32条及众多矿化蚀变点,成矿前景乐观。矿床由南、北两矿段组成。北矿段主体由13个隐爆角砾岩体组成,隐爆角砾岩体内发育黄铜矿化;南矿段在花岗斑岩与围岩的接触带发育脉状黄铜矿化,岩体内部发育细脉状和浸染状黄铜矿化。上述地质特征表明,斯如依迭尔矿床为与花岗斑岩有关的斑岩型铜多金属矿床。对斯如依迭尔矿床成矿期的热液白云母进行40 Ar/39 Ar同位素测年,获得的坪年龄为13.68±0.17 Ma,表明矿床形成于中新世。结合前人的区域地质背景和构造演化研究结果,笔者认为斯如依迭尔铜多金属矿床的成矿地质背景与冈底斯中新世斑岩型铜金矿床的相同,均为印度板块同欧亚板块碰撞后的伸展环境。     

内蒙古1017高地银多金属矿床40Ar／39Ar年龄及地质意义

1017高地银多金属矿床位于内蒙古自治区东乌珠穆沁旗境内,是近几年新发现的与华力西中期岩浆岩有关的小型银多金属矿床。矿区大地构造位置处于位于西伯利亚板块东南缘查干敖包．奥尤特．朝不楞早古生代构造．岩浆岩带东段。银多金属矿体主要赋存在上泥盆统安格尔音乌拉组砂岩和华力西中期二长花岗岩中,矿石工业类型主要为石英脉型矿石和蚀变二长花岗岩型矿石。利用40Ar-39Ar同位素定年方法对1017高地蚀变岩型银多金属矿石中热液绢云母进行同位素定年,绢云母40Ar-39Ar坪年龄to=（301．2±1．8）Ma（26）,正等时线年龄ti=（300．2±3．1）Ma（26）,反等时线年龄ti=（300．0±3．5）Ma（2σ）,测试结果可信。测试结果表明1017高地银多金属矿床形成于华力西中期,为东乌旗地区第一个Ag、Pb、Zn等多金属成矿高峰期,其成矿动力学背景为古蒙古洋壳向西伯利亚板块俯冲造山环境。     

~(40)Ar-~(39)Ar Dating of Quartz from Ore in the Baiyangping Cu-Co Polymetallic Ore-Concentrated Area, Lanping Basin, Yunnan

40Ar-39Ar fast neutron activation age spectrum of quartz in ore collected from the Baiyangping Cu-Co polymetallic ore-concentrated area, Lanping Basin, is saddle-shaped. The plateau age, minimum appearance age and isochron age shown on the spectra are 56.53±0.43 Ma, 55.52±1.78 Ma and 55.90±0.29 Ma respectively. The age data are consistent with each other within 1σ uncertainties. Because the given initial 40Ar/36Ar value of 294.7±1.14 is very close to Nier's value (295.5±5), both plateau and isochron ages may be considered as the forming time of quartz. So the age of 55.90-56.53 Ma represents the forming age of ore deposits. It is obvious that the ore deposits were formed during the Early Himalayan period.     

40Ar/39Ar Fast Neutron Activation Ages of Quartz from the J inman Vein Copper Deposit in Western Yunnan and Their Significance

Quartz samples collected from the Jinman vein copper deposit in the Lanping Basin of western Yunnan were determined by 40Ar/39Ar fast neutron activation techniques, and the spectra are characterized as being saddle-shaped. The samples yielded a plateau age of 58.05 ±0.54 Ma, a minimum appearance age of 56.76 ± 0.81 Ma and an isochron age of 54.30 ±0.15 Ma, the three ages being close to each other, indicating that the ages of the quartz samples so far determined are true and reliable. The plateau age represents the time of formation of Cu-bearing quartz veins, which is corresponding to Early Himalayan. This age is also consistent with the time at which a tectonically thermal event (60 Ma) took place within the Lanping Basin, Yunnan Province. In consideration of the fact that copper ore and other ore types in the vast area of western Yunnan are concentrated mainly in the Early Himalayan strata, the authors believe that there must have existed some indispensable key factors leading to metallogenesis on a large scale during the Early Himalayan period in western Yunnan and also constraining in union the formation of ore deposits there.     

40Ar-39Ar dating of lamprophyre dykes in the Baimazhai nickel deposit, Yunnan Province, China, and its geological significance

The Baimazhai nickel deposit,Yunnan Province,China,is located in the southern part of the Sanjiang (Tri-river) alkali-rich intrusive rock belt (Sanjiang ARIR). In this paper was conducted 40Ar-39Ar dating of two phlogopites in lamprophyres which are,as dikes,widely distributed in the orefield,and two plateau ages were ac-quired,i.e.,32.46±0.62 Ma and 32.01±0.60 Ma,respectively (averaging 32.23±0.60 Ma). The ages are obviously younger than those of the ore-hosted complex and mineralization of the Baimazhai nickel deposit. In combination with the characteristics,it is indicated that lamprophyres in the orefield and those in the Sanjiang ARIR are similar in tectonic setting,mineral assemblage and geochemistry. It is considered that lamprophyres in the orefield are the im-portant component of the Sanjiang ARIR,and the lamprophyres and ore-hosted complex in the orefield represent the products of two times of different magmatic activity from different mantle sources. On the other hand,the age of lamprophyres in the orefield is older than that of the strike-slip shearing of the Ailaoshan-Honghe fault belt,sug-gesting that the strike-slip shearing of the Ailaoshan-Honghe fault belt is not the factor leading to magmatic activity of lamprophyres in the orefield,while it is more possible that magmatic activity of the Sanjiang ARIR promoted strike-slip shearing of the fault belt.     

云南都龙锡锌矿区同位素年代学研究

笔者对云南都龙锡锌矿床以及与之相关的老君山花岗岩进行了系统的野外地质调查、成岩成矿年龄测试和岩石化学研究,探讨了成岩成矿时代、花岗岩与矿床的成因联系以及成岩成矿的构造环境.地球化学研究表明,老君山花岗岩普遍含有白云母,A/CNK＞ 1.1,K2O/Na2O＞1,碱质含量较高,镁、钙、钛等含量偏低,富集Th和U等,其主量和稀土元素含量以及稀土元素配分型式与矿区附近的片麻岩十分接近,属S型花岗岩.各类花岗岩的稀土元素和微量元素配分型式相似,暗示其为同源岩浆所形成.运用LA-ICP-MS锆石U-Pb法测得白云母花岗岩的年龄为(87.6±1.4) Ma～ (91.7±1.8) Ma,花岗斑岩为(87.3±2.1) Ma,二云母花岗岩为(84.3±2.2) Ma～(85.0±1.3) Ma;应用40Ar/39Ar法和Re-Os法分别测得矽卡岩中金云母1100～1400℃的40Ar/39Ar同位素加权平均年龄(WMPA)为(93.6±1.1) Ma,含锡钨石英脉云英岩化围岩中辉钼矿的模式年龄为(75.04±1.78) Ma～(79.16±2.43) Ma.根据花岗岩的产状和前人研究成果,将该区的岩浆侵入活动分为2期:早期(87.3±2.1) Ma～ (92.9±1.9) Ma,形成了白云母花岗岩及花岗斑岩;晚期(83.3±1.5) Ma～(85.0±1.3) Ma,形成了二云母花岗岩.与岩浆作用对应的成矿作用亦分为2期:早期(79.8±3.2) Ma～ (93.6±1.1)Ma,形成了与白云母花岗岩及花岗斑岩有关的矽卡岩型锡锌矿;晚期(75.04±1.78) Ma～(79.16±2.43) Ma,形成了与二云母花岗岩关系更密切的含锡钨石英脉.老君山花岗岩以及与之相关的锡锌钨矿是晚白垩世伸展构造环境下大规模花岗质岩浆-成矿作用的产物.     

云南景谷宋家坡铜矿床成岩成矿的Sm-Nd和^40Ar-^39Ar同位素年龄

云南景谷宋家坡铜矿床产于英安斑岩体及其围岩中三叠统火山岩地层中，矿床蚀变发育，原生矿化相对较弱，次生硫化物富集。本文报道了对该矿床的蚀变和矿化英安斑岩进行的Sm-Nd法和^40Ar-^39Ar快中子活化法同位素地质年龄测定结果。同位素年代学研究表明，Sm-Nd法和^40Ar-^39Ar快中子活化法给出了英安斑岩和原生铜矿床的形成年龄，时代为印支期中三叠世；而且^40Ar-^39Ar快中子活化法给出的年代学信息较多，其高温阶段坪年龄大致与特提斯洋闭合时间一致，而较低温阶段的表面年龄反映了燕山期甚至喜马拉雅期构造运动对成矿的改造。总之，宋家坡铜矿床的赋矿英安斑岩及区域中三叠世火山岩的成岩作用相对于特提斯洋的闭合及陆块碰撞俯冲在时间上基本同时。成矿与成岩关系密切、时间相近，且成矿经历了多期作用，原生矿化属斑岩型铜矿化，后期受盆地热卤水淋滤富集和表生氧化改造。     

黑龙江省鸡西盆地基性岩40Ar/39Ar同位素定年及其地质意义

黑龙江省鸡西盆地张新地区辉绿玢岩呈岩床状侵入晚中生代城子河组地层中;辉绿玢岩较纯净,无捕虏体,呈斑状结构,斑晶由普通辉石、斜长石组成,斑晶体积分数为35%～40%;基质由微晶斜长石、辉石、磁铁矿及玻璃质组成。辉绿玢岩⁴⁰Ar/³⁹Ar同位素定年结果表明,其等时线年龄与坪年龄在误差范围内较为接近,该辉绿玢岩的形成时代介于96～101 Ma,即形成于早白垩世晚期-晚白垩世早期的Albian-Cenomanian阶。结合区域上该期岩浆事件的特点,暗示早白垩世晚期-晚白垩世时期鸡西盆地处于古太平洋板块(Izanagi-Kula 板块 )向东亚大陆边缘斜向俯冲背景之下的弧后伸展环境。     

滇西地区下地壳铅同位素的组成及其意义

滇西地区新生代碱性侵入岩中广泛分布的麻粒岩包体可以代表该地区的下地壳岩石,为了确定滇西下地壳岩石的铅同位素组成,我们系统采集了该区碱性岩中的麻粒岩包体,挑选出其中的长石、石榴子石等造岩矿物,测定了其铅同位素组成,在Zartman等的铅构造演化模式图上,剔除个别异常的铅同位素组成,圈出投影于下地壳铅同位素演化趋势线上及附近的铅同位素分布范围,由此确定了该区下地壳的铅同位素组成的区域,并进一步结合作者先前确定的该区上地壳及上地幔铅同位素组成,构建了该区三维岩石圈铅同位素组成,并将这一结果用于滇西金顶超大型铅锌矿床的成矿物质来源的研究中,发现颇受争议的金顶铅锌矿床中的铅并非来自上地幔,而相当于下地壳来源的铅与兰坪盆地沉积岩铅二者的混合铅。     

安徽滁州琅琊山铜矿辉钼矿铼-锇同位素定年及其地质意义

首次运用铼-锇同位素方法对滁州琅琊山铜矿床中的辉钼矿进行定年。5件辉钼矿样品的模式年龄为(128.9±1.8)Ma～(130.3±1.9)Ma,187Re-187Os等时线年龄为(128.6±2.2)Ma,其加权平均方差(MSWD)为0.45,为滁州琅琊山铜矿床提供了准确的形成时限。分析结果表明,滁州琅琊山铜矿床是早白垩纪(燕山晚期)区域构造-岩浆活动的产物。琅琊山铜矿床辉钼矿中铼含量较高,推断成矿物质主要是壳幔混源,且主要是幔源。     

云南鹤庆炉坪铅多金属矿矿石矿物学特征及其地质意义

云南鹤庆炉坪铅多金属矿床是新发现的一个大型隐伏矿床, 位于北衙超大型金多金属矿床北部, 属北衙金多金属矿田斑岩-热液成矿体系的组成部分, 是该成矿体系中的新类型矿床。它是在充分研究区内基本地质条件, 对比北衙矿区的成矿特点, 认为在北衙向斜构造的轴部应该存在构造薄弱地带, 能够为万硐山正长斑岩成矿体系中的成矿流体运移提供通道和赋存空间, 同时结合良好的Pb-Au-Ag-Zn-Cu-As-Sb组合异常显示的观点指导下, 通过钻探验证而发现的铅多金属隐伏矿床。矿体沿中三叠统北衙组灰岩与下三叠统腊美组砂泥岩层间及中三叠统北衙组灰岩内层间破碎带产出; 矿石类型主要为氧化矿和混合矿, 部分为硫化矿, 其主金属元素为铅, 伴生有金、银、铁、锌等多种有用组分; 本文通过分析和总结该矿床的矿物学特征、有用组分的赋存状态及分布特征, 提出了开发利用该矿床应加强进一步开展相关研究工作的建议。     

Geology,Fluid Inclusions,and Isotopic Geochemistry of the Jinman Sediment‐Hosted Copper Deposit in the Lanping Basin,China

The Jinman Cu polymetallic deposit is located within Middle Jurassic sandstone and slate units in the Lanping Basin of southwestern China. The Cu mineralization occurs mainly as sulfide‐bearing quartz–carbonate veins in faults and fractures, controlled by a Cenozoic thrust–nappe system. A detailed study of fluid inclusions from the Jinman deposit distinguishes three types of fluid inclusions in syn‐ore quartz and post‐ore calcite: aqueous water (type A), CO₂–H₂O (type B), and CO₂‐dominated (type C) fluid inclusions. The homogenization temperatures of CO₂–H₂O inclusions vary from 208°C to 329°C, with corresponding salinities from 0.6 to 4.6 wt.% NaCl equivalent. The homogenization temperatures of the aqueous fluid inclusions mainly range from 164°C to 249°C, with salinities from 7.2 to 20.2 wt.% NaCl equivalent. These characteristics of fluid inclusions are significantly different from those of basinal mineralization systems, but similar to those of orogenic or magmatic mineralization systems. The H and O isotope compositions suggest that the ore‐forming fluid is predominantly derived from magmatic water, with the participation of basinal brine. The δ³⁴S values are widely variable between ?9.7 ‰ and 9.7 ‰, with a mode distribution around zero, which may be interpreted by the variation in physico‐chemical conditions or by compositional variation of the sources. The mixing of a deeply sourced CO₂‐rich fluid with basinal brine was the key mechanism responsible for the mineralization of the Jinman deposit.