粤东锡多金属矿床硫同位素地球化学研究

本文分析了粤东锡多金属矿床,花岗岩类和沉积岩的硫同位素成分和特征,揭示了硫从硫源转移到矿床过程中同位素组成的变化规律,确定了矿床硫的来源。     

广西大福楼锡多金属矿床成矿流体特征

通过流体包裹体岩相学和显微测温学等分析,研究大福楼矿床成矿流体的性质及其演化。研究结果表明:大福楼锡矿共发育6种类型的流体包裹体,即Ⅰ型(单相气相包裹体)、Ⅱ型(单相盐水溶液包裹体)、Ⅲ型(两相富蒸汽包裹体)、Ⅳ型(两相富液体包裹体)、Ⅴ型(含CO2相包裹体)以及Ⅵ型(含NaCl子矿物包裹体)。流体包裹体的均一温度为120~430℃,主要的成矿温度为120~145℃和380~430℃。流体包裹体盐度变化不大,介于17.00%~22.00%之间,属于高盐度流体,具有岩浆热液的标志;流体密度为0.158~1.105 g/cm3,压力为12.0~65.0MPa,属于中高压力的成矿流体。大福楼锡多金属矿床的成矿流体与大厂矿田其他矿床具有很好的一致性,表明其可能相似的来源与演化。     

个旧西凹铜-锡多金属矿床花岗岩蚀变带稀土元素特征及意义

通过分析西凹铜-锡多金属矿床蚀变岩的稀土元素特征,研究该矿的成矿物质、成矿流体来源及成矿环境等。研究结果表明:蚀变花岗岩的稀土元素配分模式与未蚀变花岗岩类似,但也存在一定的差异。相对于未蚀变花岗岩,钾化花岗岩稀土总量增高,重稀土元素(HREE)的富集程度比轻稀土元素(LREE)的大,轻稀土元素中的La,Ce的富集程度比Pr和Nd的大,次生钾长石继承了蚀变流体的稀土元素特征,可能与蚀变流体温度较高有关,且富含F,Cl和CO2有关,成矿流体来源于岩浆期后热液。绿帘石-绿泥石化花岗岩稀土总量略有降低,LREE亏损而HREE略微富集,由流体蚀变、云母类矿物的吸附作用及早期钾化蚀变共同造成。Eu异常和Ce异常,表明钾化处于相对高温氧化条件下,而绿帘石-绿泥石化则处于相对低温和还原的环境中。蚀变花岗岩中REE与成矿元素关系密切,对岩体内部找矿具有一定的指示意义。     

个旧岩体内铜多金属矿床围岩蚀变特征与成矿研究

云南个旧锡矿东矿区西部塘子凹凹陷带岩体内部新发现的铜多金属矿床,是深部找矿的新类型。矿床围岩蚀变类型较多,蚀变分带未见明显对称性,可能与热液的多期次性有关。矿床与围岩蚀变关系密切,尤其是钾长石化,可做为找矿标志。通过分析围岩蚀变特征及其与成矿的关系,总结出矿床形成的一些特点。     

云南个旧东区印支期玄武岩的时空分布

个旧东区印支期玄武岩对个旧锡多金属矿床的形成有重要的作用.作者应用玄武岩系柱状对比图和内插法作等值线的方法,分析了个旧东区印支期玄武岩的时间和空间分布情况.结果表明,个旧东区安尼锡克期的火山活动的时间和空间的大体演化趋势是,随着时间的推移火山活动的空间由南往北演变.同时,在仙山坡一带-母鸡山一带-期北山一带可能是火山喷发中心.这对个旧锡矿深部和外围的进一步找矿勘探具有一定的指导意义.     

内蒙古银都银铅锌多金属矿床成矿流体特征及成矿年代学研究

内蒙古银都银铅锌多金属矿床属于特大型银矿床, 经研究, 确定成矿过程经历了早、中、晚 3 个阶段, 分别形成以闪锌矿-磁黄铁矿-黄铜矿、方铅矿-磁黄铁矿、萤石- 白云母-碳酸盐为代表的矿物组合。其中, 早阶段为锌、铜的主成矿阶段, 中阶段则是银铅锌的成矿阶段, 晚阶段矿化较弱。激光拉曼显微探针分析表明成矿流体为 H₂O-CO₂-CH₄-NaCl 体系。包裹体研究显示成矿流体具有低盐度( 2%～5% ) 、低密度( 0. 72 ～0. 88 g/ cm³ ) 的特点, 成矿温度随着成矿流体的演变, 逐渐降低, 早、中、晚阶段分别为 340. 5℃, 282. 4℃及260. 3℃, 成矿压力为37 ～74 MPa, 成矿深度为 3. 7 ～7. 0 km。经对萤石- 白云母-碳酸盐阶段白云母的激光探针 ⁴⁰Ar-³⁹Ar年代学测定, 确定成矿年代为 135±3 Ma, 为白垩纪早期。     

浅谈锡多金属矿床控矿条件与成矿的预测

云浮金子窝锡多金属矿床位于广东四会-吴川构造带与肇庆-海丰纬向构造交汇部位。主要控矿条件包括基底地层、岩浆岩、构造等。主断裂派生的次一级断裂交切部位控制了矿床的定位和空间展布。寒武纪地层的W、Sn等元素含量较高,是重要的矿源层。后期的热事件（地热）使成矿元素发生重新分布。混合岩化和花岗岩化作用,使锡等成矿元素在矿液中逐渐富集,并在压力驱使下沿构造裂隙上升,在围岩中有利地段充填交代形成矿床。矿床存在垂直方向变化。根据矿体在空间上的原始展布和变化规律,对矿区边部和深部之隐伏矿体进行了预测。     

云南普洱大平掌铜多金属矿床同位素地球化学研究及意义

大平掌矿区位于滇西南澜沧江火山岩带中南段的南部,夹持于NNW向区域性李子箐断裂(F4)和酒房断裂(F1)。是典型的与中酸性火山岩有关的VHMS型矿床。通过对硫、铅、氢氧同位素地球化学特征研究,探讨了成矿流体来源及演化。同位素(S、Pb、H、O)研究结果显示:硫同位素δ34S(-2.4‰～2.7‰,平均值为-0.4‰),铅同位素组成(206Pb/204Pb≈18.195—18.942;207Pb/204Pb≈15.408—15.641;208Pb/204Pb≈37.599—38.659),δD值介于-78‰—-59‰,石英矿物的δ18O≈7.2‰—11‰,石英中的水δ18OH2O≈-3‰—0.35‰,研究结果表明:硫主要来源于火山喷气作用,海水硫酸盐对成矿作用的贡献很小;铅同位素组成具有壳-幔混合源铅的特点,深源物质参与成矿明显;成矿热液流体应是深循环海水与岩浆水的混合流体。     

桂北一洞锡多金属矿床锡石标型特征研究

桂北一洞锡多金属矿床为一主要产出于基性岩体中的锡矿床。原生锡矿石类型主要为锡石—云英岩型,锡石—电英岩型,锡石—石英型、锡石硫化物型及部份纤维状锡石。对各类型矿石中锡石进行微量元素,稀土元素地球化学及其标型特征的研究,有助于进一步理解锡石形成物质来源,锡矿成因类型划分等问题。     

Origin of ore-forming fluids of the Dachang Sn-polymetallic ore deposit: Evidence from helium isotopes

The ore genesis model for the Dachang Sn- polymetallic ore deposit has long been in dispute, and the major debate focuses on whether the stratiform and massive orebodies formed during the Yanshanian magmatic-hydro- thermal event or they were products of Devonian syn-sedimentary exhalative-hydrothermal event. This note presents new helium isotope data from fluid inclusions of four pyrites and one fluorite. The pyrites were collected from the stratiform and massive orebodies in the deposit, and their 3He/4He ratios are significantly higher than 1, ranging from 1.7 to 2.5 Ra, which indicates a mantle component in the responsible hydrothermal fluids. It is suggested that the ore-forming fluids were a mixture of deep circulating seawater and a mantle-derived fluid, which are similar to many of those modern submarine hydrothermal fluids. In contrast, the fluorite, collected from a granite-related hydrothermal vein in the deposit, shows a low 3He/4He ratio of 0.7 Ra, which indicates no mantle component involvement in the fluids. Hence, the helium isotope data indicate that the two kinds of fluids from the Dachang deposit may have different origins. Together with other geological and geochemical evidence, it is suggested that the stratiform and massive ore formation has no genetic relation to the Yanshanian granite. Rather, they were likely formed during Devonian submarine exhalative-hydrothermal processes.     

Origin of ore-forming fluid in the Piaotang tungsten deposit in Jiangxi Province: Evidence from helium and argon isotopes

The Piaotang tungsten deposit in Jiangxi Province is one of the most important tungsten deposits in the South China Tungsten Metallogenic Province.In this study,we selected wolframite and chalcopyrite from the main mineralizing stage of the Piaotang tungsten deposit,and analyzed the helium and argon isotopic compositions in fluid inclusions of these minerals.The results show a 3He/4He ratio of 0.17 to 0.86 R/Ra,which fall within the range between continental crust(0.01―0.05 R/Ra) and air-saturated water(1 R...     

Minerogenetic mechanism of Rushan gold deposit, Shandong Province——Evidence of ore-forming fluid and H, O, Sr isotopes

granite, quartz-vein type gold deposit, ore-forming fluid, origin of deposit.     

西藏蒙亚啊铅锌矿床成矿流体来源及特征

探讨西藏蒙亚啊铅锌矿床成矿流体来源及其特征,结合区域典型矿床研究厘定矿床成因类型。通过矿床近矿体蚀变灰岩和热液成因方解石碳-氧同位素及成矿不同期次石英氢-氧同位素分析手段,结合流体包裹体岩相学、温度和盐度测试研究,分析了矿床成矿流体的特征及成矿流体来源。结果表明,成矿早期流体以岩浆水为主,成矿晚期有大量天水混入;主成矿期成矿流体总体具有中高温和中低盐度特征,成矿从早期到晚期流体降温趋势明显。矿床形成与岩浆作用关系密切,矿床类型属于远接触端夕卡岩型铅锌矿床。     

煎茶岭含钴硫化镍矿床成矿作用研究

对煎茶岭硫化镍矿床地质背景、岩体及矿石的地质地球化学特征进行了研究。结果表明：煎茶岭大型含钴硫化镍矿床的形成与镁质超基性岩体密切相关且具有特殊性，其成矿物质主要来源于深部岩浆；源自上地幔局部熔融的母岩浆，在通过上地幔岩石圈上升侵位过程中，就地发生硫化物熔离作用和硫化作用，形成早期的富镍矿体和部分贫矿石；稍后的蛇纹石化作用是形成该矿床中后期富镍矿体的主要原因；元古代岩浆作用、硫化作用和蛇纹石化作用是煎茶岭镍矿床主要的成矿作用方式；成矿机制是岩浆分结 硫化熔离 蛇纹乒化。认为该镍矿床PGE含量较低互贫铜，Cu／Ni值极低，成因上属岩浆型矿床，但后期存在热液成矿作用。     

He-Ar isotope geochemistry of the Yaoling-Meiziwo tungsten deposit,North Guangdong Province: Constraints on Yanshanian crust-mantle interaction and metallogenesis in SE China

Isotopic abundances and ratios of He and Ar found in inclusion fluids in pyrites formed in the Yaoling-Meiziwo tungsten miner-alization epoch show that the concentration of 4He varies widely,from 1.54×10-7 cm3 STP/g to 2609×10-7 cm3 STP/g.3He is 0.759×10-12 cm3 STP/g-3.463×10-12 cm3 STP/g.3He/4He is 0.0043-4.362 Ra,varying from crustal to mantle values.The concen-tration of 40Ar ranges from 0.624×10-7 cm3 STP/g to 8.89×10-7 cm3 STP/g.The 40Ar/36Ar varies extensively,from 330 to 2952,between atmospheric and crustal or mantle radiogenic values.Mantle-derived He is present in ore-forming fluids and the calcu-lated average proportion of the mantle He is 22%;the maximum is 67%.Our research results show that mantle-derived fluids play a significant role in tungsten mineralization.The fractionation of He and Ar indicate that there was 4He-enriched air-saturated water(MSAW) in the ore-forming fluid.The ore-forming fluid was a mixture of mantle fluid,crustal magmatic fluid and MSAW.The occurrence of a mantle component in ore-forming fluid indicates the large-scale W and Sn mineralization,including Yaol-ing-Meiziwo,in southeastern China was the result of crust and mantle interaction.The underplating or intrusion of voluminous basaltic magma formed by partial melting of the upper mantle provided the necessary heat to cause partial melting of the crust and the generation of voluminous S-type granitic magmas.Crustal magmatic fluid and mantle fluid with high 3He/4He were released from magma crystallization and fractionation,mixed with the circulating modified air-saturated water,and filled the extensional tectonic fractures,leading to the formation of world-class W and Sn deposits in southeastern China.     

新疆白干湖钨锡矿流体包裹体特征及成因

白干湖钨锡矿床位于新疆祁漫塔格加里东褶皱带的转折部位,是东昆仑西段1个较好的钨锡(金)矿区,对白干湖矿区主成矿阶段形成的含黑钨矿石英脉中发育的包裹体进行岩相学及测温研究.研究结果表明:矿区主要发育3类包裹体:气液两相水溶液包裹体(I)、水溶液-CO2三相包裹体(Ⅱ)以及纯CO2两相包裹体(Ⅲ);Ⅰ型包裹体液相组分主要为NaCl水溶液,含少量KCl,其均一温度变化范围为160-310℃,盐度为1.82％～16.43％;Ⅱ型水溶液-CO2三相包裹体气相组分含有CO2及CH4等组分,均一温度为247～320℃,w(NaCl)为2.8％～9.4％;Ⅲ型CO2两相包裹体含量较少,均一温度为19.8～27.7℃;白干湖钨锡矿床成矿流体为中低盐度、中高温的NaCl-H2O-CO2体系.在成矿过程中,由于温度及压力降低,流体发生相分离成为较高盐度的水溶液流体和较低盐度的富CO2流体,钨锡成矿物质趋向于富集在中高盐度水溶液相中,并导致白干湖钨锡矿的成矿作用.