Geochemical Studies of Sodium Enriched Metavolcanite Series in the Area of Longbohe Copper Deposit,Yunnan Province,SW China：Nd,Sr and Pb Isotopic Characteristics and Chronology     

常向阳  朱炳泉  莫向云 《中国地球化学学报》2002,21(2):163-169

The chronological data obtained by a variety of dating methods have confirmed that the sodium enriched metavolcanite series in the area of the Longbohe copper deposit at Jinping, Yunnan Province, was formed during the Proterozoic (its Pb−Pb isochron age=1595±75 Ma), corresponding to the Dahongshan Group sodium enriched metavolcanites. The Sm−Nd isochron age of 1336±46Ma should represent the time at which this series of volcanic rocks experienced spilitization in response to sodium metasomatism, equivalent to the time of sedimentation of the Ailaoshan Group and Yashan Group rocks. The Rb−Sr ages of the volcanic rocks and the Pb−Pb ages of copper ores have recorded the events of strong dynamic metamorphism and of strong reworking-metallogenesis of copper during the Jinningian period. Similarities in forming age, rock assemblage and isotopic characteristics between the sodium enriched metavolcanite series and the Dahongshan Group sodium enriched metavolcanite series have provided new clues to the exploration of the Dahongshan-type copper deposits in this area. Granted jointly by the National Natural Science Foundation of China (Nos. 49702022, 40073001) and the State 973 Program (No. G1999043215).  相似文献   

Structure cristalline d'une ménéghinite naturelle pauvre en cuivre,Cu_0,58Pb_12,72(Sb_7,04Bi_0,24)S₂₄Crystal structure of a Cu-poor natural meneghinite,Cu_0.58Pb_12.72(Sb_7.04Bi_0.24)S₂₄     

Yves Moëlo  Pierre Palvadeau  Nicolas Meisser  Alain Meerschaut 《Comptes Rendus Geoscience》2002,334(8):529-536

Cu-poor meneghinite from La Lauzière Massif (Savoy, France) has the composition (electron microprobe) (in wt%): Pb 59.50, Sb 20.33, Bi 1.19, Cu 0.87, Ag 0.05, Fe 0.03, S 17.62, Se 0.05, Total 99.64. Its crystal structure (X-ray on a single crystal) was solved with R1=0.0506, wR2=0.1026, with an orthorhombic symmetry, space group Pnma, and a=24.080(5) Å, b=4.1276(8) Å, c=11.369(2) Å, V=1130.0(4) Å³, Z=4. Relatively to the model of Euler and Hellner (1960), this structure shows a significantly lower site occupancy factor for the tetrahedral Cu site (0.146 against 0.25). Among the five other metallic sites, Bi appears in the one with predominant Sb. Developed structural formula: Cu_0.15Pb₂(Pb_0.53Sb_0.47)(Pb_0.46Sb_0.54)(Sb_0.75Pb_0.19Bi_0.06)S₆; the reduced one: Cu_0.58Pb_12.72(Sb_7.04Bi_0.24)S₂₄. The formation of such a Cu-poor variety seems to be related to specific paragenetic conditions (absence of coexisting galena), or to crystallochemical constraints (minor Bi). To cite this article: Y. Moëlo et al., C. R. Geoscience 334 (2002) 529–536.  相似文献   

全站仪轴系补偿原理及检验方法探讨   总被引：1，自引：0，他引：1  

叶晓明  凌模  谢方 《测绘信息与工程》2003,28(3):40-43

全面阐述了全站仪的轴系补偿相关理论和实践，指出了我国检验规程的不足之处，提出了改进方法。  相似文献   

冀西北东坪金矿床成矿流体的来源研究   总被引：1，自引：0，他引：1  

莫测辉  王秀璋  程景平  梁华英 《矿物岩石地球化学通报》1997,(2)

冀西北东坪金矿床成矿流体的来源研究＊莫测辉王秀璋程景平梁华英（华南农业大学资源环境学院，广州５１０６４２）（中国科学院广州地球化学研究所，广州５１０６４０）关键词金矿床成矿流体来源岩浆热液大气降水热液侵入岩体中的金矿床乃至岩体接触带或附近地层中的金矿...  相似文献   

渗流场反分析及其在多孔介质中的应用     

许模 《地质灾害与环境保护》1996,(2)

本文讨论了复杂地质环境中渗流场的反分析问题，利用地下水流数值模拟结合最优化技术，通过对地下渗流场的模拟和寻优，求得描述地下含水介质非稳定渗流场的重要参位──渗透系数和给水度的模型解，并应用于各向同性的多孔介质渗流场反分析实例中。  相似文献   

山东荣成沽河流域水资源系统分析     

许模  费美高 《地质灾害与环境保护》1996,7(3):50-55,63

流域水资源系统由降水产流，以及通过水文下垫面的转换，形成的地表径流和地下水流流组成。本文将复杂的沽河流域水 资源系统分解成多个子系统，利用频谱分析方法对各个水资源子系统的转换功能进行定量的分析刻画，并利用地下含水介质子系统的转换特征函数－频率响应函数求取水文地质参数，丰富了水文地质参数的获取途径。  相似文献   

新疆哈密黄山─镜儿泉地区金矿床（点）矿物标型特征的研究     

唐菊兴  阳正熙  李承德  慕纪录 《矿物岩石》1996,(3)

本文通过镜下鉴定，结合电子探针分析、Ｘ衍射分析等，总结了研究区各金矿床（点）的矿物物性、成分、分布等特征。矿物学的研究表明，整个成矿过程和构造动力变质密切相关。  相似文献   

Bismuth and cobalt minerals as indicators of stringer zones to massive sulphide deposits, Iberian Pyrite Belt     

E. Marcoux  Y. Moëlo  J. M. Leistel 《Mineralium Deposita》1996,31(1-2):1-26

The stringer zones and commonly the interaction zone at the base of the massive sulphide mounds in the Iberian Pyrite Belt contain bismuth and cobalt minerals that are not found in the overlying massive sulphides. These are fairly rare cobalt sulphoarsenides (cobaltite, alloclasite, galucodot) that were formed at the beginning of the massive sulphide genesis, and fairly common bismuth sulphides (bismuthinite, hammarite, wittichenite, cosalite, kobellite, joseite, etc.), including species rare at world scale (nuffieldite, giessenite, jaskolskiite) that were deposited from last stage high-temperature (> 300 °C) copper-bearing fluids containing Bi (Te, Se). The last stage fluids precipitated chalcopyrite containing Cu, Bi, Te, (Se) sulphosalts at the base of the sulphide mound to form a high cupriferous zone. Their interaction with the massive sulphides is reflected by the formation of an exchange zone, a few metres thick, showing chalcopyrite disease textures, at the base of the mound; this zone forms the upper limit of potentially economic copper enrichment and of bismuth minerals. Gold is undoubtedly in part, if not totally, related to this last phase. The bismuth concentrations being equivalent in the massive sulphides and the stringers, the presence of bismuth minerals in the stringer zones results from high-temperature conditions combined with a rarity of galena, which impedes absorption of available Bi. The distribution of these bismuth minerals provides a basic mineralogical zoning in the stringer zone, with a deep, low-aS₂ zone containing native bismuth and tellurides and a shallow, higher-aS₂ zone in contact with the massive ore sensu stricto and containing complex bismuth sulphides. These results make it possible to distinguish between sulphide veinlets belonging to stockwork zones of massive orebodies and veinlets of an ambiguous nature, and provide mineralogical criteria for the proximity of copper-rich zones. They enrich the very complex mineralogy of the Iberian Pyrite Belt.  相似文献   

裂隙岩体中的对流扩散研究     

陈尤雯  莫海鸿 《岩土力学》1997,18(3):47-52

揭示一个基于代数拓扑理论的裂隙网络中物质弥散模型，还给出了应用于网络中的对流扩散的对应性原理的证明。应用拓扑理论给出的框架，使其起了一个数据结构的组织者的作用，由此得到网络中每一个分支上的浓度的解。这个解是在拉普拉斯空间上的解析解。网络中任意点在任何时刻的浓度可以很方便地用数值拉氏反变换求出。  相似文献   

冀西北东坪金矿床含金石英脉石英流体包裹体Rb-Sr等时线及其地质意义   总被引：8，自引：2，他引：8  

莫测辉  王秀璋  程景平  梁华英 《地球化学》1997,26(3):20-27

用石英流体包裹体Ｒｂ－Ｓｒ等时线法测得产于碱性岩体中具有超大型潜力的东坪金矿床含金石英脉的年龄为（１０３±８）Ｍａ，远晚于赋矿岩体的就位时间（元古宙），显示了成岩与成矿是两期不同构造运动的产物，两者之间没有直接的成因联系。８７Ｓｒ／８６Ｓｒ示踪结果显示成矿物质主要来源于赋矿碱性岩体。研究结果认为，东坪金矿是后期与大气降水热液有关的改造成矿作用的产物。  相似文献