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51.
金矿床地球化学异常模式研究的新进展 总被引:14,自引:0,他引:14
论述了近十年来金矿床地球化学异常模式研究的新进展,90年代以前研究和建立了石英脉和蚀变岩型金矿地球化学异常模式,90年代以来,研究和建立了中国主要类型金矿床地球化学导航异常模式,热液金矿床和原生叠加晕理想模式,金矿床包裹体气晕,离子晕及其叠加晕理想模式。 相似文献
52.
长城矿产在铬铁矿体及临近矿体的铂砂矿中。呈块状聚集体或细脉状,分布在硫铱矿的边缘并交代它。不透明,金属光泽,钢灰色,条痕黑色。莫氏硬度H_M=3.7,显微硬度VHN_(20)=165kg/mm~2。均质性,无解理。计算密度D_(calc.)=11.96g/cm~3。7个电子探针分析的平均化学成分(%):S 7.2,Cu 0.3,Te 0.4,Ir 41.2,Pt 2.8,Bi 47.2,总量99.1。简化的化学式为IrBiS。5条最强X射线粉晶衍射线(hkl,d,I)为:210,2.75(70);211,2.51(60);311,1.860(100);440,1.090(50);600,1.027(50)。X射线粉晶衍射图谱与马营矿相似。进行对比后,长城矿可以指标化为等轴晶系、空间群P2_13。由X射线粉晶衍射线求得α=0.6164(4)nm,V=0.2342nm~3,Z=4。 相似文献
53.
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
54.
Yu ZuxiangInstitute of Geology Chinese Academy of Geological Sciences Baiwanzhuang Beijing 《《地质学报》英文版》1997,71(4):486-490
Changchengite occurs in chromite orebodies in dunite and in platinum placer deposits in chromite orebodies nearby. The mineral occurs as massive aggregates or veinlets on margins of iridisite (IrS2) and replaces it. Opaque. Lustre metallic. Colour steel-black. Streak black. Hm = 3.7. VHN20= 165 kg/ mm2. Isotropic. Cleavage none. Density 11.96 g/ cm3. Seven electron microprobe analyses give the following mean chemical results (wt. %): S 7.2, Cu 0.3, Te 0.4, Ir 41.2, Pt 2.8 and Bi 47.3 with total 99.1. The simplified formula is IrBiS. The strongest X-ray powder diffraction lines (hkl, d, I) are 210, 2.75 (70); 211, 2.51 (60); 311, 1.860 (100); 440. 1.090 (50) and 600, 1.027 (50). The X-ray powder diffraction pattern is similar to that of mayingite. After the diffraction data are indexed the mineral is determined to be cubic. The space group is P213 with a = 0.6164(4) nm, V = 0.2342 nm3 and Z = 4. 相似文献
55.
The design of roadbed-abutment transition part is always a challenging problem in transportation engineering, especially in permafrost distribution zone. A new type of roadbed-abutment transition part on permafrost was presented, and long-term observation was conducted for the deformation and the thermal regime of a roadbed-abutment transition part in the constructing Qinghai-Tibet Railway. In this paper, a new structure was presented and the observed settlements both in the subgrade and the base and its dependency with the thermal regime (permafrost table) were analyzed. In conclusion the roadbed-a-butment transition method for permafrost distribution zone was evaluated. 相似文献
56.
57.
新材料是发展高新技术产业的基础。根据广西的矿产资源优势和在矿物材料方面的研究基础和技术力量,提出了加强工艺矿物学研究,大力发展广西新型矿物材料的研究开发方向,特别提出了超细改性矿物粉体材料、环保矿物材料、节能保温矿物材料、高技术陶瓷材料和合成矿物晶体材料等材料体系中的重点开发方向。 相似文献
58.
59.
Helen Ruth Aspaas 《GeoJournal》2004,61(3):281-289
Women in many rural areas of the US often engage in small-scale businesses as one of several avenues for contributing to household
incomes. In those geographical areas that contain a significant minority population, many of the women's businesses display
the cultural diversity of the regions in which they live. Likewise, women's roles as economic providers as well as wives and
mothers are reflected in the manner in which they operate their businesses. Candida Brush suggests that women's strategies
for operating their businesses are highly integrative because women's business decisions are intertwined with familial responsibilities,
household economic demands and desires to contribute to their communities. Hispanic and Native American women in the Four
Corners region of southwestern US and African American women in central Virginia participated in interviews in which they
responded to numerous short answer and open-ended questions about their businesses and decision-making strategies. From these
interviews an image emerges of rural minority business women who are operating their businesses at the nexus of family obligations,
economic necessities, cultural ties and with a commitment for serving their communities.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
60.
Problems associated with tourism development in Southern Africa: The case of Transfrontier Conservation Areas 总被引:2,自引:0,他引:2
Sanette Ferreira 《GeoJournal》2004,60(3):301-310
Tourism in Southern Africa is synonymous with the wildlife safari. In the post-colonial era the establishment of so-called
‘peaceparks’ that straddle the borders of states has come to be seen as a key not only to increasing tourism in the Southern
African region, but also to the modernizing of conservation policies and the development of rural economies. This paper focuses
on the global and continental presence of transfrontier conservation areas, the link between conservation and tourism development,
and the current factors that constrain and influence the realization of an ‘African Dream’ — ‘establishment of the greatest
animal kingdom’. The unstable political situation in Zimbabwe and how this negatively affects wildlife conservation and tourism
in the Gonarezhou part of the Greater Limpopo Transfrontier Park, serves as a case study.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献