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1.
邦布金矿床位于青藏高原雅鲁藏布江结合带东段南侧,矿体受大型脆-韧性剪切带的次级断裂控制,其一系列地质地球化学特征显示该矿属于造山型金矿。其含金石英脉中黄铁矿的流体包裹体3He/4He=0.174～1.010Ra,40Ar/36Ar=311.9～1724.9,矿物δ34S=2.8‰～4.7‰,平均3.6‰;围岩中不含金黄铁矿流体包裹体3He/4He=0.01137Ra,40Ar/36Ar=1709.7,矿物δ34S=6.5‰,显示邦布金矿成矿流体主要由地壳流体组成,但其中有地幔流体的加入,幔源He占2.7%～16.7%。由壳幔相互作用导致的幔源流体的加入是邦布金矿重要的成矿条件。在印度板块与欧亚大陆板块碰撞过程中,形成切穿地壳的纵向剪切带,深源地幔流体上升,与地壳来源的富CO2流体混合,由于温度和压力下降和流体沸腾导致含金硫化物和石英结晶,并在其次级断裂构造中形成邦布金矿体。  相似文献   

2.
江西相山沙洲铀矿床He、Ar同位素特征及其地质意义   总被引：2，自引：0，他引：2       下载免费PDF全文
严冰  严寒  魏文风  曹阳  李健 《地质论评》2014,60(3):624-634
江西相山沙洲铀矿床位于中国华南赣杭铀成矿带南西段、华南中生代陆相火山岩带西缘。本次工作系统采集了矿区内成矿期黄铁矿、方解石,开展了稳定同位素和稀有气体同位素研究。研究表明方解石的δ13CV-PDB和δ18OV-SMOW值分别为-3.2‰~-7.4‰,8.5‰~15.2‰,成矿流体中的碳主要源自地幔;黄铁矿样品流体包裹体的n(40Ar)/n(36Ar)值为303~326,n(3He)/n(4He)值为0.193~2.946 Ra;成矿流体的He—Ar同位素组成是地壳流体[n(3He)/n(4He)值较低,n(40Ar)/n(36Ar)值与大气近似]和地幔流体[高n(3He)/n(4He)和n(40Ar)/n(36Ar)值]两端元的不同比例混合产物。  相似文献   

3.
刘军  李铁刚  段超 《地质学报》2018,92(7):1432-1446
八家子金矿床是华北克拉通北缘夹皮沟金矿带中的重要金矿床之一,赋存于太古宙花岗-绿岩带内。矿体多呈脉状产出,受NW向夹皮沟断裂控制,与中生代正长斑岩有成因联系。本文在八家子矿床选取8件黄铁矿样品开展了Rb-Sr定年,获得Rb-Sr等时线年龄为218.6±1.5Ma(MSWD=1.4),初始Sr同位素比值ISr=0.71047。成矿流体的δ18 OW值为3.2‰~5.1‰,δDW值为-100.7‰~-88‰。成矿流体主要来源于岩浆流体,混合部分变质流体和大气降水。金属硫化物的δ34S值介于-0.2‰~+7.9‰之间,均值+5.7‰,表明硫主要来自深源岩浆。黄铁矿中流体包裹体3 He/4 He值为1.05~1.20Ra,平均值1.13Ra。地幔流体参与成矿作用的比例为11.6%~13.2%,地壳流体占主导地位。八家子金矿的成矿时代为晚三叠世,形成于华北克拉通北缘的碰撞后伸展环境。  相似文献   

4.
邓阜仙钨锡多金属矿床位于南岭多金属成矿带中段的一个重要石英脉型黑钨矿矿床。本文尝试采用与钨矿成矿关系密切的长石、石英开展了He-Ar与H-O同位素的研究,结果显示石英流体包裹体的~3He/~4He测定值为0.006~0.0244 Ra,明显低于地壳值(0.01~0.05 Ra)。成矿流体中~(40)Ar/~(36)Ar变化范围在303.3~867.8,高于饱和大气雨水~(40)Ar/~(36)Ar值(295.5)。石英包裹体中,δ~(18)O测试值变化于+10.3‰~+13.7‰之间,平均为+12.4‰;石英中包裹体H_2O的δD测试值变化于-72.9‰~-100.1‰之间,平均为-89.28‰,表明成矿流体为岩浆水与大气降水的混合。两种不同的同位素体系均表明本区的成矿作用为邓阜仙岩体的期后热液受到了裂隙中大气降水的影响。  相似文献   

5.
桂东北富贺钟地区是广西重要的有色金属基地之一, 在姑婆山复式岩体的西南缘产出有新路、水岩坝和珊瑚3个主要钨锡多金属矿田。本文对不同矿田典型矿床分别开展了稀有气体同位素研究, 根据黄铁矿流体包裹体He、Ar、Ne同位素组成, 进一步讨论了区内钨锡成矿流体来源和壳-幔成矿作用过程。结果表明, 黄铁矿流体包裹体3He/4He=0.53~4.53 Ra、40Ar/36Ar=315.58~600.55、38Ar/36Ar=0.18688~0.19102、20Ne/22Ne=9.737~9.848、21Ne/22Ne=0.0291~0.0304, 显示成矿流体为地壳流体、幔源流体和饱和大气水的混合物, 成矿过程中有地幔物质的加入, 地幔He约占8.7%~75.7%。结合区内成岩、成矿的测年资料及岩石成因等综合分析认为, 区内中生代发生了多期次壳-幔相互作用, 且作用强度经历了强→弱→强的演化过程, 分别导致了姑婆山岩体主体岩性(165~160 Ma)和晚期细粒花岗岩(154~151 Ma)的侵位, 以及钨锡多金属成矿作用(136~100 Ma), 成矿与晚期的细粒花岗岩同位但不同时。  相似文献   

6.
赣南黄泥湖铀矿床成矿流体的氦、氩同位素组成及其意义   总被引：1，自引：0，他引：1  
黄泥湖铀矿床是赣南典型的热液铀矿床,文章通过对该矿床成矿期形成的萤石、方解石和黄铁矿中流体包裹体的He、Ar同位素的测定表明,黄泥湖铀矿床流体包裹体中3 He/4 He值为0.007~2.272Ra(绝大部分在0.024~1.754Ra),40 Ar/36 Ar值为191.6~1126.1(绝大部分高于295.5),认为成矿流体的氦具有壳-幔混合来源特征,其中幔源流体占主导地位,地壳流体端元为含有一定放射性成因Ar的大气降水。结合前人研究成果,认为黄泥湖铀矿床为深源热液成因,与晚燕山期华南岩石圈伸展作用有关。  相似文献   

7.
石湖地区金、银多金属矿床位于太行山中北段,产出于太古界阜平群变质岩系,燕山期麻棚岩体的周边。本文以石湖地区代表性矿床为例,根据多金属矿床黄铁矿流体包裹体中He、Ar同位素及与黄铁矿共生的石英流体包裹体中C、H、O同位素组成,探讨了石湖地区金、银多金属矿床成矿流体来源。分析结果表明石湖地区金、银多金属矿床黄铁矿流体包裹体中3He/4He介于0.43~2.40 Ra,40Ar/36Ar介于477~879,显示出本区金、银多金属矿床的成矿流体为地幔流体与地壳流体混合的产物。石英包裹体中δDV-SMOW介于-62‰~-105‰,δ18OV-SMOW介于9.6‰~13.8‰,表明成矿流体为岩浆水与大气降水的混合;δ13CPDB介于-3.5‰~-5.0‰,表明矿区成矿热液来自地幔。氢、氧、碳同位素体系与氦、氩同位素体系的示踪具有一致性,均显示出石湖地区金、银多金属矿床成矿流体为地幔流体与地壳流体混合的产物。  相似文献   

8.
粤北诸广南部铀矿田是我国重要的花岗岩型铀矿产地之一,有关诸广南部花岗岩型铀矿田的成因,多年来一直存在较大的争议。本文以诸广南部铀矿田典型铀矿床成矿期萤石、方解石和黄铁矿中流体包裹体为测试对象,研究了成矿流体的He、Ar同位素地球化学。研究表明,萤石流体包裹体的~3He/~4He比值为0. 021～0. 186Ra,~(40) Ar/~(36)比值为298. 4～2515. 7;方解石流体包裹体的3He/4He比值为0. 027～0. 209Ra,~(40) Ar/~(36)比值为295. 9～327. 2;黄铁矿流体包裹体的3He/4He比值为0. 021～1. 543Ra,~(40) Ar/~(36)比值为326. 9～1735. 1; He-Ar同位素系统显示成矿流体的3He/4He比值略高于地壳氦同位素特征值(0. 01～0. 05Ra),但低于幔源氦同位素特征值(6～9Ra),~(40) Ar/~(36)比值接近或高于大气氩的同位素组成(~(40) Ar/~(36)=295. 5),成矿流体为壳-幔混合来源。结合H-O、He-Ar、C和Sr等多元同位素证据表明,成矿流体由两个端元组成:一是含有一定放射性成因Ar的大气降水的地壳流体,二是含幔源He的地幔流体。进一步研究表明,受NNW向断裂控制的棉花坑、书楼丘、长排等铀矿床受地幔流体影响比较大,而受NE向断裂控制的蕉坪、东坑、烟筒岭铀矿床受大气降水影响比较大。  相似文献   

9.
为查明青海驼路沟新型独立钴(金)矿床的成因和成矿物质来源,文章对矿区发育的块状、条带状和浸染状黄铁矿矿石进行了黄铁矿流体包裹体氦氩同位素和黄铁矿硫、铅同位素测试。结果表明,不同类型矿石的成矿流体氦、氩同位素组成基本一致,3He/4He介于0.10~0.31Ra(平均0.21Ra),40Ar/36Ar比值为302~569(平均373),反映钴矿化流体主要来源于在赋矿岩系中深循环的大气降水;矿石黄铁矿硫同位素值分布集中且接近于零,δ34S变化于-4.5‰~+1.5‰,集中在-1.8‰~-0.2‰,显示深部来源;矿石铅以高放射性成因为特征(206Pb/204Pb>19.279、207Pb/204Pb>15.691、208Pb/204Pb>39.627),且自地层围岩→区域早古生代火山岩→矿石依次明显增大,可能指示高放射性成因矿石铅主要是由以深循环大气降水来源为主的热液不断从围岩地层中淋取而来。  相似文献   

10.
近年来,青藏高原北缘喀喇昆仑铅锌找矿取得重大突破,新发现的火烧云超大型铅锌矿床已成为中国最大的铅锌矿床,矿石矿物以菱锌矿、白铅矿、水锌矿为主,也是世界第二大非硫化物铅锌矿床。矿体呈似层状产出,埋藏浅,主要为褐色块状矿石,Pb+Zn平均品位近30%。可分为3个成矿阶段。早期铅锌硫化物成矿阶段(方铅矿、闪锌矿、方解石)、中期铅锌非硫化物成矿阶段(菱锌矿、锰氧化物→菱锌矿、白铅矿、石膏)与晚期表生氧化阶段(水锌矿)。硫化物阶段方铅矿的δ34S为-18.9‰～-4.2‰,非硫化物阶段热液石膏的δ34S为-20.6‰～-7.5‰,继承了硫化物阶段矿物的硫同位素特征。Pb同位素组成集中,具有地壳来源特征,二叠系—白垩系可能提供了金属成矿物质。方解石的δ18CPDB为0.6‰～3.1‰,δ18 OSMOW为15.3‰～24.6‰,菱锌矿的δ18 CPDB为-2.7‰～4.5‰,δ18 OSMOW为10.4‰～26.1‰,来源于碳酸盐岩的溶解作用;白铅矿的δ18 CPDB为-7.7‰～4.3‰,δ18 OSMOW为9.3‰～24.3‰,同位素发生漂移,可能是与大气降水的混入有关。硫化物成矿阶段方解石中流体包裹体的3 He/4 He值为0.05～0.39 R/Ra,40 Ar/36 Ar值为296.2～428.9,方铅矿中流体包裹体的3 He/4 He值为0.03 R/Ra,40 Ar/36 Ar值为290.0,成矿流体可能为中温、低盐度、中低密度的还原性壳源流体;非硫化物成矿阶段菱锌矿中流体包裹体的3 He/4 He值为0.10～0.43 R/Ra,40 Ar/36 Ar值为290.6～295.3;白铅矿中流体包裹体的3 He/4 He值为0.08R/Ra,40 Ar/36 Ar值为293.5,成矿流体可能为中低温、低盐度、中密度的壳源流体与大气降水混合流体。综上所述,火烧云超大型铅锌矿床是盆地边缘褶皱逆冲+构造流体+次生交代成矿系统的产物,硫化物成矿阶段为构造热液成因,非硫化物成矿阶段为围岩交代成因,后期发生叠加氧化作用,形成大量水锌矿。  相似文献   

11.
最新的流行病学研究表明,空气中较高浓度的悬浮细颗粒可能对人类的健康有不利的影响。根据该项研究显示,由于心脏病、慢性呼吸问题和肺功能指标恶化而导致死亡率的升高与细尘粒子有关。这些研究结果已经促使欧盟于1999年4月出台了限制空气中二氧化硫、二氧化氮、氧化氮、铅和颗粒物含量的法案(1999/30/EC),对各项指标包括对可吸入PM10颗粒的浓度提出了新的限制性指标。PM10颗粒是指可以通过预分级器分离采集的气体动力学直径小于10μm的细颗粒。目前研究的兴趣重点逐步偏向PM2.5这些更细微颗粒物,PM2.5这种颗粒物对健康有明显的不利影响。在欧盟指令2008/50/EC中,对PM10和PM2.5都提  相似文献   

12.
Brick-tea-type fluorosis is a peculiar endemic disease in China, which had been discovered in minority areas of western China since 1980, and distributed mainly in Tibet, Inner Mongolia, Gansu, Xinjiang, Qinghai and parts of Sichuan Province. The prevalence rate of fluorosis in Tibetan and Mongolian nationality people was higher. Epidemiological investigation showed that fluorosis morbidity and degrees were different in different brick-tea drinking areas, and it was probably caused by drinking various kinds of brick tea from different regions. Therefore, we collected 33 samples of brick tea from six provinces where minority nationalities were accustomed to drinking a large quantity of brick tea. F concentrations were determined by the combustion hydrolysis-ion selective electrode method. The results showed that among the brick teas, the F concentrations ranged from the minimum 74.1 mg/kg in Yunnan Province to the maximum 991.2 mg/kg in Sichuan Province. Besides, there was a great difference among the various kinds of brick tea, and F concentrations decreased in the order of Kang brick tea, Green brick tea, Black brick tea, Mi brick tea, Fu brick tea, Chitsu ping tea, Puerh tea, and Tuo tea. The average F concentration in brick teas was 431.92 mg/kg.  相似文献   

13.
日本北海道音调津的球状石墨   总被引：1，自引：0，他引：1  
本文利用光学显微镜、X射线衍射仪、透射电镜等手段对日本北海道音调津球状石墨的成因、结构等进行研究,认为日本北海道音调津球状石墨中除了石墨外,还存在镍黄铁矿﹑黄铜矿﹑磁黄铁矿等金属硫化物矿物。通过透射电子显微镜观察发现音调津石墨中大部分是椭圆状石墨颗粒,高分辨晶格条纹主要是非晶态结构,但是同时也发现了结晶良好的石墨。高结晶度石墨的存在可能是在硫化物Fe-Ni-Cu的触媒作用下形成的。天然球状石墨的微结构和性状研究对天然石墨的形成和开发应用有重要意义,对新型碳材料的制备技术有重要科学意义。  相似文献   

14.
The textural relationships and structural states of optically isotropic labradorite from the Manicouagan, Quebec, impact structure have been examined by light (optical) and transmission electron (TEM) microscopy. Two distinct diaplectic glasses have been recognized based on their contrasting morphology, timing and the inferred modes of formation. The earliest isotropic bands and grain-scale isotropism (maskelynite) optically exhibit a gradational,in situ transformation from crystalline plagioclase with preservation of relict textures (twins, grain boundaries). The same transformation from crystalline to amorphous structure is observed in TEM to occur heterogeneously at scales on the order of the unit cell. The progressive transformation of optical properties reflects an increase in the volume fraction and eventual coalescence of these amorphous units. This maskelynite-type diaplectic glass is interpreted to form in the solid-state directly from crystalline material during the compressional phase of the shock wave. The other isotropic material occurs in spatially discrete tensiongashes and planar deformation features (PDFs) that overprint the maskelynite-type glass. This second type of diaplectic glass (PDF-type) is developed homogeneously within a given glass band and exhibits sharp crystal-glass boundaries, in contrast to the gradational boundaries of the maskelynite-type glass. PDF-type glass is interpreted to form by melting in tensional release zones during passage of the rarefaction wave. These observations emphasize the ability of naturally shocked rocks to preserve subtle evidence of variations in the shock process from highly transient events.  相似文献   

15.
通过介绍普者黑地区的岩溶地貌特征,借鉴石林和桂林的研究模式,对普者黑的岩溶地貌形成机理进行了深入研究,并针对普者黑独特的亚热带高原岩溶地貌的特征,阐述了其研究的科学价值。  相似文献   

16.
On June 5, 2009, a catastrophic rockslide-debris flow occurred at the crest of the Jiweishan Mountain in Wulong, Chongqing, China. Approximately five million cubic meters of limestone blocks slid along a weak interlayer of bituminous and carbonaceous shale. The source mass descended from the upper part of the slope rapidly, crossing a 200-m wide and 50-m deep creek in front of it. Blocked by the opposite steep creek wall, the sliding mass changed its direction and traveled a further 2.2 km along the creek in debris-flow mode, finally forming a large accumulation zone with an average depth of 30 m. This is one of the most catastrophic rockslide events in recent years in China. It buried 12 houses and the entrance of an iron mining tunnel where some 27 miners were working inside. Ten people died, 64 missing, and eight wounded. Immediately after this disaster happened, the government organized an expert team to assist the rescue work. As one of the geological experts, the author did a lot of field investigations and collected first-hand information. Multi-methods including the remote sensing, 3D laser scanning, geophysical exploration, and numerical modeling were used for analyzing the characteristics and the triggering mechanism of the Wulong rockslide. The preliminary investigation results reveal that this rockslide with poor geological conditions was mainly induced by the gravitation and the karst effect and also affected by the previous mining activities. The research in this paper is meaningful and useful for further research on such kind of rockslides that are geologically similar to the Wulong rockslide.  相似文献   

17.
捕虏体麻粒岩是了解下地壳形成和演化的重要样品。汉诺坝新生代玄武岩中的二辉麻粒岩捕虏体样品中富含各种硫化物相,主要类型有:①孤立产出的球状出溶硫化物;②矿物颗粒之间或颗粒内的粗晶硫化物;③次生硫化物包裹体群;④裂隙充填硫化物。电子探针分析表明,硫化物的矿物成分均为贫镍磁黄铁矿,(Ni+Co+Cu)/Fe(原子比)远小于0.2;(Fe+Cu+Co+Ni)/S(原子比)比地幔岩的磁黄铁矿小,多小于0.875,反映了一种S过饱和环境。各种产状的磁黄铁矿中Au、Ag都有一定的含量,其平均值分别为0.19%～0.22%(Au)、0.01%～0.02%(Ag),反映下地壳的麻粒岩化与金矿化的成因联系。磁黄铁矿的Ni、Co、Cu含量与S正相关,说明微量重金属元素与S具有同源的关系,由于地幔去气伴随S而进入下地壳。  相似文献   

18.
Abstract The 6-km-thick Karmutsen metabasites, exposed over much of Vancouver Island, were thermally metamorphosed by intrusions of Jurassic granodiorite and granite. Observations of about 800 thin sections from the Campbell River and Buttle Lake area show that the metabasites provide a complete succession of mineral assemblages ranging from the zeolite to pyroxene hornfels facies around the intrusion. The most important observations are as follows. (1) The compositional change of Ca-amphiboles with increasing metamorphic grade is not straightforward. The tremolite component decreases from the prehnite–actinolite facies to the greenschist facies with a compensating tschermak component increase, but the tendency is not clear thereafter. Instead, the edenite component increases from the amphibolite facies to the pyroxene hornfels facies. (2) The most pargasitic Ca-amphibole occurs in high-Fe2+/Mg metabasite from the greenschist/amphibolite transition zone. (3) The reasons for such irregular compositional trends, even in the rather uniform MORB-like composition of the Karmutsen metabasites, are non-ideal solid solutions of Ca-amphibole at low temperature and the effective control by bulk rock composition in the amphibolite facies. (4) The data from this study support, but do not prove, a transition loop for the actinolite–hornblende compositional gap rather than a solvus. If the gap is a solvus, its shape is asymmetric, and is highly dependent on the other compositional parameters such as Fe3+/Al and Fe2+/Mg. (5) The XNaA/XA±XAb) ratios between Ca-amphibole and plagioclase are most useful as an indicator of metamorphic grade even within the amphibolite facies, and these change systematically from 0.2 to 0.5 from the greenschist to pyroxene hornfels facies. (6) The compositional trend of Ca-amphibole from the Karmutsen metabasites indicates a typical low-P/T metamorphic facies series on a Rbk–Gln–Tr–Ts diagram.  相似文献   

19.
夏季长江河口潮间带反硝化作用和N2O的排放与吸收   总被引：15，自引：1，他引：15  
采用培养箱乙炔抑制和现场静态箱法,于夏季(7月)在长江河口潮滩潮间带进行了采样,研究表明,长江河口潮滩水体自身N2O产生速率很低,在潮汐淹没期沉积物是上覆水体N2O的来源,其来自沉积物中反硝化、硝化等氮素循环的多个反应过程,沉积物中N2O自然产生速率在0.10～8.50μmol/(m2·h)之间,反硝化速率在21.91～35.87μmol/(m2·h)之间。退潮出露期中潮滩是大气N2O的排放源犤交换速率在-11.03～13.17μmol/(m2·h)之间犦,5～10cm地温是影响N2O排放速率的显著性因素;低潮滩-大气界面N2O排放、吸收速率在-5.75～0.49μmol/(m2·h)之间。总体上看,中潮滩是大气N2O的排放源;而低潮滩对大气N2O有明显的吸收作用。潮滩植被(海三棱草和底栖藻类)的光合作用明显抑制了N2O的排放并可能导致吸收,而其呼吸作用则增加了N2O的排放,潮间带-大气界面N2O的排放和吸收与CO2的排放、吸收有显著的正相关关系。  相似文献   

20.
Komatiites are mantle-derived ultramafic volcanic rocks. Komatiites have been discovered in several States of India, notably in Karnataka. Studies on the distribution of trace-elements in the komatiites of India are very few. This paper proposes a simple, accurate, precise, rapid, and non-destructive wavelength-dispersive x-ray fluorescence (WDXRF) spectrometric technique for determining Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th in komatiites, and discusses the accuracy, precision, limits of detection, x-ray spectral-line interferences, inter-element effects, speed, advantages, and limitations of the technique. The accuracy of the technique is excellent (within 3%) for Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Zr, Nb, Ba, Pb, and Th and very good (within 4%) for Y. The precision is also excellent (within 3%) for Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th. The limits of detection are: 1 ppm for Sc and V; 2 ppm for Cr, Co, and Ni; 3 ppm for Cu, Zn, Rb, and Sr; 4 ppm for Y and Zr; 6 ppm for Nb; 10 ppm for Ba; 13 ppm for Pb; and 14 ppm for Th. The time taken for determining Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th in a batch of 24 samples of komatiites, for a replication of four analyses per sample, by one operator, using a manual WDXRF spectrometer, is only 60 hours.  相似文献   

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