Yixunite and Damiaoite—A Twin of New Native Alloys of Indium and Platinum from the Yanshan Mountains     

Yu ZuxiangInstitute of Geology  Chinese Academy of Geological Sciences  Baiwanzhuan  Beijing 《《地质学报》英文版》1997,71(4):480-485

Yixunite and damiaoite Were found in a cobalt- and copper-bearing platinum ore vein of a contact metasomatic deposit. The chief ore minerals are bornite, chalcopyrite, magnetite and carrollite. The platinum minerals include moncheite, sperrylite, daomanite, cobalt malanite and cooperite. Yixunite and damiaoite occur as immiscible globules, 1.0 to 2.0 mm in diameter. Yixunite is always in the central part of a globule. It is opaque with metallic lustre, bright white colour and black streak. HM = 5.8; VHN50 = 634 kg/mm2 (573-681 kg/ mm2); insoluble in HCl, HNO3, HF or H3PO4; no cleavage; no magnetism. Density is hard to measure because of small grain size. Calculated density = 18.21 g/cm3. Reflective colour is bright white with a yellowish tint. Isotropic. The mean analytical results (ranges) (%) are: Pt 82.8 (81.8-83.6), In 16.4(15.6-17.1) and total 99.2. The empirical formula (based on 4 atoms) is Pt2.993 In1.007 . The five strongest lines of X-ray diffraction (hkl, d,I) are 111, 2.30 (100); 200, 1.99 (  相似文献   

金矿脉分形特征及找矿意义研究     

李洪志  宋玉国 《地质与资源》1997,6(1):54-62

各种类型的金矿脉常呈不规则的几何形状产出,对它们用欧几里德方法进行描述和分析,不仅难以精确地说明其几何形态特征,有时甚至无法作出实际测量,因此也就很难掌握其产状变化的准确趋势,给金矿床的定量定位预测造成了困难.分形理论为获得有关隐伏矿床(脉)分布的更为准确的信息提供了有利工具.通过对招远灵山和河东两个典型金矿床矿脉分维数、几何丰度和有效紧密度等研究,讨论了分形理论在紧密结合地质特征条件下,客观准确揭示不规则矿脉变化规律及在找矿预测等方面的应用前景.  相似文献   

河北小营盘石英—碳酸盐型金矿成矿地质特征     

邱小平  潘淼 《黄金地质》1997,3(4):29-35

小营盘金矿赋存在稳定的缓倾斜石英脉中，但单纯的白色石英脉仅有微弱矿化，只有经过Ｓ懊断层剪切拉张破裂和叠加铁白云石化及硫化物蚀变的石英脉才能成为矿体，金矿体的顶底面常被铁白云石蚀变岩和糜棱岩所包裹，而且部分蚀变岩的金含量也达到工业品位，石英脉与蚀变岩作用构成矿体。因此，早期金成矿作用的时代大致与铁白云蚀变同期，含金铁白云石蚀变岩的δ＾１３Ｃ值平均为－４．１３‰，Ｐｂ－Ｐｂ等时线年龄为２７１１±２３８  相似文献   

程海断裂带断层泥中石英碎砾表面SEM特征及断层活动状态的分析   总被引：4，自引：0，他引：4  

俞维贤  王彬  毛燕  杨继武 《中国地震》2004,20(4):347-352

根据断层泥中石英碎砾表面SEM特征的鉴定研究，可将程海断裂中、北段断层泥中石英碎砾表面SEM形貌特征分为6类，这表明该段断裂经历了长期多期次活动，强烈活动时间在中晚更新世；5件样品中均未见破裂类(Io)的石英颗粒，表明程海断裂全新世以来强烈活动的频度相对较低。石英碎砾表面机械作用特征的分类统计研究显示：程海断裂中、北段晚更新世以来，断层所经历的活动方式以粘滑活动为主。  相似文献   

The Bulong Gold Deposit-a Quartz-Barite Vein Type Gold Deposit in Xinjiang:Geological Characteristics and S, He and Ar Isotopic Compositions   总被引：2，自引：0，他引：2  

YANG Fuquan  WANG Yitian  MAO Jingwen Institute of Mineral Resources  Chinese Academy of Geological Sciences  Beijing 《《地质学报》英文版》2004,78(2):404-416

The Bulong gold deposit, located in the southwest Tianshan in China, occurs in the Upper Devonian finegrained clastic rocks. The gold orebodies are controlled by an gently inclined interlayer fractured zone. They are hosted only in quartz-barite veins though there are barite veins and quartz veins in the ore district. The δ34S values of pyrite in the ores range from 14.6‰ to 19.2‰ and those of barite from 35.0‰ to 39.6‰, indicating that the sulfur was derived from the strata. 3He/4He ratios of fluid inclusions in pyrite are 0.24-0.82 R/Ra, approximating to that of the crust. The 40Ar/39Ar ratios range from 338 to 471, slightly higher than that of the atmosphere. 40Ar /4He ratios of ore fluids range from 0.015 to 0.412 with a mean of 0.153. Helium and argon isotope compositions of fluid inclusions show that the ore fluids of the Bulong gold deposit were mainly derived from the crust.  相似文献   

小秦岭金矿含金石英脉中黄铁矿晶体的表面微形貌研究   总被引：1，自引：0，他引：1  

张良钜 《岩石矿物学杂志》2004,23(2):167-172

利用微分干涉显微镜、扫描电镜、透射电镜等对小秦岭金矿含金石英脉中黄铁矿晶体的表面微形貌进行了研究。黄铁矿晶体的{210}面上发育自由生长层，表明{210}面是F面，其生长机理受二维成核层生长所制约。除简单的五角十二面体外，其他形态黄铁矿晶体的{210}面上也发育有自由生长层。{210}面上的正条纹有些是由{100}面上生长层的边缘台阶在{210}面上叠堆形成，另一些正条纹则是{210}面上生长层边缘台阶堆叠的产物。透射电镜和电子衍射花样研究表明，负条纹黄铁矿晶体是由30～50nm大小的核团经自动定向附生作用形成，每个核团不是单晶体，而是由许多早先在溶液中形成的小微晶聚合而成。这些特征表明负条纹黄铁矿晶体是在溶液过饱和度极高和温度梯度小的理想环境中形成，它的形成与杂质无关。PBC理论和唐纳-哈克定律能较好地解释自然界中黄铁矿晶体{100}面上普遍发育自由生长层、而{210}面上自由生长层极为罕见的原因。除日本释迦内矿区黑矿之上的浮岩凝灰岩中产生出负条纹黄铁矿晶体外，在石英脉型金矿床中也有负条纹黄铁矿晶体产出。  相似文献   

山东龙口大顶金矿地质特征及找矿方向     

鄢全树  马衍峰  徐进 《矿产与地质》2004,18(1):22-25

重点介绍大顶金矿区的地质特征及区内主要矿脉体(36号矿脉群)特征，同时，对控矿因素作了一定的分析，初步总结了36号矿脉群在双顶矿段北东缘的成矿规律，指明了本矿区的找矿标志及下一步的找矿方向。  相似文献   

石英脉型辉钼矿矿床多建造地球化学异常特征   总被引：1，自引：0，他引：1  

朱柏松  王成良  张方君 《物探与化探》2004,28(2):114-115,118

通过对石英脉型辉钼矿床水系沉积物和区域成矿带多建造地球化学异常特征的研究,为寻找石英脉型钼矿床提供地球化学论据。  相似文献   

Weathering: Toward a Fractal Quantifying   总被引：1，自引：0，他引：1  

Klaudia Oleschko  Jean-Francois Parrot  Gerardo Ronquillo  Sergey Shoba  Georges Stoops  Vera Marcelino 《Mathematical Geology》2004,36(5):607-627

Weathering occurs over a wide range of scales. To link features through these scales is a major challenge for interdisciplinary weathering studies. Fractal approach seems to be specially useful for this purpose. We introduce a multistep fractal weathering assessment scheme devoted to extract fractal weathering classifiers from texture analysis of the mineral's image. Our scheme enables to quantitatively estimate the global and local information about the geometry of the weathering pattern. This information is basic to develop geometrical indices of weathering, which can significantly enrich the common qualitative and semiquantitative weathering assessment schemes. To justify the fractal approach, a strong statistical self-similarity has been documented for both the weathering and fresh features of two common silica minerals: quartz and biogenic A-opal (phytolith) over four orders of length scales. The procedure is fast, drastically reduces thresholding bias, promises to be universal, it is valid for genetically different minerals and rock types, scale independent, and specially useful for monitoring the changes in the mineral's roughness during the alteration. Two of the proposed classifiers seem to be potentially useful for direct application in the field and be used by nonspecialist.  相似文献   

The magmatic–hydrothermal transition—evidence from quartz phenocryst textures and endoskarn abundance in Cu–Zn skarns at the Empire Mine, Idaho, USA     

Zhaoshan Chang  L.D. Meinert 《Chemical Geology》2004,210(1-4):149-171

Information about the magmatic to hydrothermal transition is preserved in late-stage features of quartz phenocrysts and endoskarn alteration in some Cu–Zn skarn deposits such as the Empire Mine in Idaho. Important features include: (1) quartz phenocrysts with strong resorption textures such as vermicular zones of igneous groundmass cutting primary quartz cathodoluminescence banding, (2) anomalous amounts of endoskarn (more than 50% of mineralized rock), (3) high F activities as evidenced by fluorite as an accessory mineral in igneous rocks, in alteration assemblages, and in fluid inclusions and by high F in hydroxyl sites in igneous biotite and amphibole, and (4) direct association of Zn, which normally is deposited distally at low temperature, with Cu in proximal locations and in endoskarn. These features are explained by the following model: (1) F lowers the solidus temperature of the magma, thus changing the timing, temperature, and duration of hydrothermal fluid exsolution. (2) Upon magmatic vapor saturation the F-rich hydrothermal fluids form bubbles that adhere to quartz phenocrysts and chemically corrode/tunnel into the quartz forming vermicular resorption textures. (3) F-rich hydrothermal fluids also promote the formation of endoskarn; silicic rocks are attacked by F-rich fluids in the same sense that carbonate wall rocks are dissolved by weakly to moderately acidic hydrothermal fluids. (4) Low fluid exsolution temperature facilitated by high F activity promotes high Zn/Cu ratios in proximal locations due to the solubility of Zn relative to Cu at lower temperatures. This model may be applicable at other localities such as the world-class Cu–Zn skarn Antamina mine, as well as some tin and rapakivi granites.  相似文献