华北地台钼（铜）矿床成矿年代学研究——辉钼矿铼－锇年龄及其地质意义

华北地台北缘的燕辽和南缘的东秦岭两个钼矿带闻名遐迩。本文用同位素稀释－等离子体质谱法，直接测定了燕辽钼矿带中兰家沟钼矿床的Ｒｅ－Ｏｓ等时线年龄为（１８６．５±０．７）×１０６ａ，杨家杖子和肖家营子钼矿床的Ｒｅ－Ｏｓ模式年龄为（１８７±２）×１０６～（１９１±６）×１０６ａ和（１７７±５）×１０６ａ，小寺沟和寿王坟铜（钼）矿床的Ｒｅ－Ｏｓ模式年龄为（１３４±３）×１０６ａ和（１４８±４）×１０６ａ，大湾和大庄科钼矿床的Ｒｅ－Ｏｓ模式年龄为（１４４．４±７．４）×１０６ａ和（１４４．７±１０．７）×１０６～（１４７．１±６．６）×１０６ａ。结合东秦岭钼矿带内钼矿床的Ｒｅ－Ｏｓ年龄，证明华北地台内有早元古代钼矿化，两个钼矿带中的钼或铜（钼）矿床的成矿时代主要为印支期和燕山早期或中—晚期。Ｒｅ－Ｏｓ法不仅是直接测定钼（铜）硫化物矿床成矿年龄的一种新手段，而且所获结果为研究区域成矿演化提供了确实的依据。     

香港中生代火成岩U—Pb法年龄测定

香港中生代侵入岩和火山岩２２个锆石和独居石新的Ｕ－Ｐｂ年龄,揭示了中侏罗世至早白垩世火山－深成作用分为４期,（１６４．６±０．２）×１０＾６～（１５９．３±０．３）×１０＾６ａ,（１４６．６±０．２）×１０＾６～（１４６．２±０．２）×１０＾６ａ,（１４３．７±０．３）×１０＾６～（１４２．５±０．３）×１０＾６ａ,（１４０．９±０．２）×１０＾６～（１４０．４±０．２）×１０＾６ａ。从最早知道的     

湖南千里山花岗岩体的Nd－Sr同位素及岩石成因研究

本文利用Ｒｂ－Ｓｒ等时线方法测得第一阶段似斑状黑云母花岗岩、第二阶段等粒黑云母花岗岩和第三阶段花岗斑岩的成岩年龄分别为（１５２±９）×１０￣６ａ、（１３７±７）×１０￣６ａ～（１３６±６）×１０￣６ａ和（１３１±１）×１０￣６ａ。Ｓｒ－Ｎｄ同位素资料表明各阶段花岗质岩石均基本上源于地壳物质的重熔。与钨多金属矿化有关的似斑状黑云母花岗岩和等粒黑云母花岗岩属同一岩浆体系分异演化的产物，其钕模式年龄（ｔ＿（ＤＭ）＝２３０７×１０￣６ａ）反映出成岩物质来自早元古宙地层的重熔。与铅－锌－银矿化有关的花岗斑岩的钕模式年龄（ｔ＿（ＤＭ）＝１２８４×１０￣６～１５７８×１０￣６ａ）示意出其成岩物质来自中元古宙地层的重熔。     

横岭关铜矿床地球化学研究

对横岭关铜矿床中稀土元素、同位素和矿物包裹体地球化学研究表明，矿床形成温度为３５０℃±３０℃；压力为３８×１０~５Ｐａ～２４０×１０~５Ｐａ；盐度为３０ｗｔ％～４２ｗｔ％；ｌｏｇｆｏ_２为－３０．４１～－３１．４７；ｌｏｇｆｓ_２为－５．４～－８；ｐＨ值为７．３；ｌｏｇｆｃｏ_２为－２．４９；铜的溶解度（ｌｏｇｍ_（Ｃｕ））为－５．８７～－２．２１。围岩的铅－铅同位素年龄为１７７５×１０~６ａ，矿石的铅－铅同位素年龄为１８４５×１０~６ａ；矿石硫同位素组成，δ~（３４）Ｓ为－８．１‰～３６．９‰，显示出硫同位素为非平衡特征；碳酸盐岩的碳同位素组成，δ~（１３）Ｃ为－７．１‰～－２．６‰，δ~（１３）Ｃ_（∑Ｃ）为－５．３‰；成矿流体的氢氧同位素组成具有变质热卤水的特点，认为该矿床属于变质热卤水成矿。     

晋宁期后华南陆壳增生作用—海相碳酸锰矿的Nd同位素制约

扬子地台南缘早震旦世，古生代和晚三叠世海相碳酸锰矿石的εＮｄ（Ｔ）值分别是－４．６－－５．５，－８．１－－９．０和－３．５－－４．２。Ｚ１－Ｃ１期间，它们的Ｎｄ模式年龄Ｔ２ＤＭ平均为１９３１±４６Ｍａ，εＮｄ（Ｔ）－Ｔ演化线与亏损地幔演化线交点年龄为１９５０Ｍａ，ｄ（Ｔ）／ｄσ＝０．９６。Ｎｄ同位素组成特征表明：华南陆壳晋宁期前的增生作用主要发生在早元古代的１９３１±４６Ｍａ前，晚元古代地壳增生作     

东秦岭地区钼矿床的铼-锇同位素年龄及其意义

金属矿床的成矿年龄多年来一直是矿床地质工作者关注的问题之一。中国地质科学院岩矿测试技术研究所建立的铼－锇同位素定年实验室，为研究钼矿床的形成时代提供了新的手段。因辉钼矿是最主要的含铼矿物之一，且基本上不含普通锇，其中所含＾１８７Ｏｓ是由＾１８７Ｒｅ衰变而来，故放射成因＾１８７Ｏｓ的积累是矿物年龄及铼含量的函数。本文采用同位素稀释－等离子体质谱法，测定了东秦岭钼矿带中几个不同类型的大型钼矿床的Ｒｅ－     

东秦岭地区钼矿床的铼－锇同位素年龄及其意义

金属矿床的成矿年龄多年来一直是矿床地质工作者关注的问题之一。中国地质科学院岩矿测试技术研究所建立的铼－锇同位素定年实验室，为研究钼矿床的形成时代提供了新的手段。因辉钼矿是最主要的含铼矿物之一，且基本上不含普通锇，其中所含￣（１８７）Ｏｓ是由￣（１８７）Ｒｅ衰变而来，故放射成因￣（１８７）Ｏｓ的积累是矿物年龄及铼含量的函数，本文采用同位素稀释－等离子体质谱法，测定了东秦岭钼矿带中几个不同类型的大型钼矿床的Ｒｅ－Ｏｓ年龄：黄龙铺碳酸岩脉型钼（铅）矿氏的Ｒｅ－Ｏｓ年龄为印支期，其余的斑岩型钼矿床和斑岩－矽卡岩型钼（钨）矿床的Ｒｅ－Ｏｓ年龄均为燕山期。     

与东秦岭超大型钼矿床有关的钾长石—石英条纹岩研究

东秦岭超大型钼矿带是世界上重要的钼矿带之一,带内分布着几个大型至超大型钼矿床。与这些大型－ 超大型钼矿床有关的岩体顶部都发育了钾长石石英条纹岩。钾长石石英条纹岩中钾长石富Ｓｉ,Ｋ,贫Ｎａ;其三斜度、有序度低。石英包裹体中Ｆ－ ,Ｋ＋高,ＣＯ／ＣＯ２ 低,缺少ＣＨ４,形成温度为４００℃～５００℃。氢氧同位素分析表明：δ１８ Ｏ＝ ９．０６×１０－ ３ ～１０．０３×１０－ ３ ,δＤ＝ － ５７．２２×１０－ ３ ～－ ７５．１０×１０－ ３ ,证明钾长石石英条纹岩的物质来自晚期岩浆热液。     

河北牛圈热泉型银（金）矿床成因

牛圈银（金）矿床是冀北地区近几年来新发现的重要银矿床之一。本文从硅质角砾岩成因，成矿的阶段划分，成矿物理化学条件，矿物包裹体等方面入手探讨了该矿床成因并提出了成矿模式，该矿床成矿温度稍高（２２０－３５０℃），成矿压力很低（小于２６０×１０＾５Ｐａ）形成深度为０．４２－０．８６ｋｍ亚地表环境，成矿流体以低盐度（小于３．３５ｗｔ％ＮａＣｌ）富Ｋ＾＋，Ｃｌ＾－，Ｆ＾－，ＳＯ＾２－４，贫Ｎａ＾＋，Ｃａ＾２     

等离子体质谱铼—锇同位素测年法研究及其应用

采用同位素稀等离子体质谱铼－锇同位素测年法，测定了中国的几个钼矿床和铜镍化物矿床成矿年龄。Ｒｅ和＾１８７Ｏｓ的空白值分别为７０和１０ｐｇ。年龄测定精度在３％左右。     

白云鄂博稀土矿床中辉钼矿的铼-锇同位素年龄

白云鄂博铁稀土矿床的形成年龄一直是个有争论的问题，采自该矿床东采场的辉钼矿样，通过镜下对矿物结构构造的研究，认为辉钼矿是矿区晚期矿脉形成阶段的矿物，它的铼－锇同位素年龄为（４３９±８）×１０＾６ａ。此结果从另一侧面说明该矿床在加里东期有一期成矿作用。     

Re—Os Isotope Ages of Molybdenum Deposits in East Qinling and Their Significance

Dating of metallic ore deposits has been one of the problems concerned with by ore geologists for many years.The establishment of the Re-Os Isotope Laboratory at the Institute of Rock and Mineral Analysis,Chinese Academy of Geological Sciences, has provided us with a new technique to carry out geochronological studies of molybdenum ores.As one of the most important Re-bearing minerals, molybdenite contains almost no common osmium, but ^187Os was derived completely from decay of ^187Re, with ^187Os content as the function of Re content in the mineral .An ID-ICP-MS technique has been used in this study,and Re-Os isotopic ages of several large molybdenum deposits of differ-ent types from the East Qinling molybdenum belt have been determined.It is indicated that the Huanglongpu carbonatite vein-type molybdenum-(lead) deposit has a Re-Os age corresponding to Indosinian,while the rest porphyry-type molybdenum deposits and porphyry-skarn-type molybdenum-(tungsten) deposits have Re-Os ages corresponding to Yenshanian.     

The Coupled Re—Os and Pt—Os Systematics：A Theoretical Consideration

The ^190Pt-^186Os system should be a unique tracer for mantle processes be-cause both Pt and Os are concentrated in the mantle.The ^190Pt-^186Os system will also be a good supplement to the ^187Re-^187Os system for dating and tracing mantle pro-cesses because the ^190Pt-^186Os system is not so easily contaminated by crustal materials as the ^187Re-^187Os system.In turn,the application of the ^187Re-^187Os system to Pt-enriched materials uncontaminated by crustal materials will indirectly refine the half life of ^190Pt.The ^190Pt is refined.In the coupled ^187Re-^187Os and ^190Pt-^186Os sys-tematics,an ^186Os*/^190Pt-^187Os*/^187Re Concordia diagram similar to the ^206Pb*/^238U-^208Pb*/^232Th Concordia can be constructed.In such a Concordia diagram,a date will be obtained so long as the ^190Pt-^186Os system remains closed even if the ^187Re-^187Os sys -tem is contaminated by crustal materials.In addition ,for the coupled ^190Pt-^186Os and ^187Re-^187Os systematics,the mantle processes and the interactions between the mantle and the crust will be described by two ratios:^186Os/^188Os and ^187Os/^188Os .The coupled ^187Re-^187Os and ^190Pt-^186Os systematics will be a powerful tool in the investigation of the geodynamic history of the Earth because the ^187Re-^187Os system is sensitive to the interactions between the mantle and the crust,while the ^190Pt-^186Os system is a good tracer for mantle processes.     

Re–Os systematics of the Raobazhai peridotite massifs from the Dabie orogenic zone, eastern China

The Raobazhai ultramafic massif of the ultrahigh pressure Sulu–Dabie orogenic belt, central China, is thought to be a segment of subcontinental lithospheric mantle that was subducted and exhumed during the Triassic collision of the North China and Yangtze cratons. We performed a Re–Os isotopic study of peridotites from the massif, associated with major and trace element analysis and textural examination. Os (1.02 to 6.28 ppb) and Re (0.004 to 0.376 ppb) concentrations are typical of orogenic lherzolite values, and ¹⁸⁷Os/¹⁸⁸Os ratios (0.1157 to 0.1283) are all similar to or lower than the proposed primitive upper mantle value. ¹⁸⁷Os/¹⁸⁸Os is roughly correlated with ¹⁸⁷Re/¹⁸⁸Os, and strongly correlated with Al₂O₃. These correlations can be explained by radiogenic ingrowth of ¹⁸⁷Os since an ancient partial melting event. T_MA model ages (1.7 to 2.0 Ga) of refractory peridotites from the lower massif are consistent with the model age (1.8 Ga) obtained from the ¹⁸⁷Os/¹⁸⁸Os vs. Al₂O₃ correlation at ~1% Al₂O₃. This age cannot distinguish the cratonic provenance of the Raobazhai massif, since similar Re–Os model ages have been obtained from both the North China and the Yangtze cratons. The poor quality of the ¹⁸⁷Os/¹⁸⁸Os vs. ¹⁸⁷Re/¹⁸⁸Os correlation indicates that the Re/Os ratios were disturbed, perhaps during Triassic subduction. The mainly lherzolitic samples of the upper massif, which were most strongly affected by this process, have porphyroclastic textures with fine-grained olivine, pyroxene and amphibole neoblasts, suggesting Re mobility during recrystallization in the presence of fluids.Previous studies of ultramafic xenoliths from arc volcanics demonstrate that slab-derived melts or fluids can both scavenge mantle Os and add substantial amounts of radiogenic Os to the suprasubduction mantle. In Raobazhai, both trace element patterns and the abundance of hydrous phases provide evidence for extensive interaction with fluids during subduction and/or exhumation. Nevertheless, the strong correlation between ¹⁸⁷Os/¹⁸⁸Os and Al₂O₃, and the high Os concentrations of these rocks indicate that Os isotopic ratios, and probably even Os concentrations, were essentially unaffected by this process. Assuming that the arguments favoring a suprasubduction setting for the Raobazhai massif are valid, these data provide evidence that Os systematics are sometimes surprisingly robust, even above subduction zones.     

Re-Os同位素在晚新元古代至早寒武世测年及古环境演绎中的应用进展

晚新元古代至早寒武世是地球演化历史上极其重要的时期,该时期地层年龄框架的厘定以及古海水、古大气、古气候等方面的研究一直是国际地学界的关注热点。Re-Os同位素测年法是近十几年来兴起的地层测年法,其对于晚新元古代至早寒武世重要时间节点上沉积的富有机质黑色页岩具有测年及示踪古环境的双重优势。本文以晚新元古代至早寒武世地层为例,阐述了Re-Os同位素测年法在年代地层学研究中的应用,通过与大量的、精确的锆石U-Pb年龄对比,论证了Re-Os同位素测定沉积地层年龄的可靠性。对于震旦系陡山沱组地层建阶及留茶坡组地层的年代学研究,黑色页岩Re-Os同位素测年法可发挥重要的作用。结合前人所做的Sr同位素变化曲线以及收集的晚新元古代—早寒武世Os同位素初始值的测试数据,阐述了Os同位素在该时段古环境演绎及Ni-Mo-V多金属层来源追溯上发挥的作用。黑色页岩难以进行~(87)Sr/~(86)Sr的分析,而Os同位素初始值能较好地弥补这一缺陷,二者的相互结合将为晚新元古代至早寒武世古环境演化的研究作出贡献。本文指出,随着Re-Os同位素分析技术的发展以及更多实验流程的建立,该项技术在未来年代地层学,尤其对一些古老地层的年代厘定具有广阔的应用前景。     

云南个旧老厂细脉带型锡矿白云母40Ar-39Ar年龄及其地质意义

细脉带型锡矿是云南个旧矿田老厂矿区的主要矿床类型之一.文章利用40Ar-39Ar同位素测年方法对老厂细脉带型锡矿床白云母-电气石-石英脉中的白云母进行了年龄测试.结果显示,该白云母的40Ar-39Ar同位素坪年龄为(827±07)Ma,表明其形成时代为晚白垩世.进一步结合区域资料,指出包括个旧锡多金属矿床在内的右江褶皱带内与岩浆作用有关的矿床具有相同的成矿地质背景,为华南晚中生代岩石圈大规模伸展的产物.     

广西珊瑚钨锡矿床含钨石英脉中白云母40Ar-39Ar年龄及其地质意义

广西珊瑚钨锡矿床是中国南岭钨锡成矿带内的典型矿床之一,其矿石类型主要为钨锡石英脉型、钨锑萤石石英脉型及含钨石英角砾脉型等3种.本研究对采自该矿床长营岭75中段和35中段含钨石英脉的2件白云母样品进行了40Ar-39Ar快中子活化年龄测定,获得白云母的Ar-Ar坪年龄分别为(100.8±0.7)Ma和(102.7±1.7...     

云南泸水钨锡矿床微量钾矿物40Ar-39Ar马鞍形年龄谱的含义

采用⁴⁰Ar-³⁹Ar计时方法测定滇西泸水钨锡矿床的白云母、石英、电气石和绿柱石等矿物的年龄，其中微量K矿物（石英、电气石和绿柱石）均形成含过剩⁴⁰Ar的马鞍形年龄谱。研究表明鞍形谱最小年龄的含义比较复杂，有些样品的最小年龄接近于成矿年龄，而有些样品的最小年龄大于甚至远大于成矿年龄。     

粤北瑶岭钨矿成矿相关花岗岩的锆石SHRIMP年龄与40Ar/39Ar成矿年龄及其地质意义

粤北瑶岭钨矿区存在石英脉型黑钨矿和矽卡岩型白钨矿两种成矿类型,与石英脉型黑钨矿成矿同期形成的白云母的40Ar/39Ar年龄为(149.44±0.73)Ma,与华南中生代燕山期大规模的W、Sn成矿作用的年龄一致,代表石英脉型黑钨矿的成矿年龄.与石英脉型黑钨矿成矿相关的隐伏灰白色黑云母花岗岩的SHRIMP锆石年龄为(158...