Showing papers by "Kier Group published in 1982"
TL;DR: Based on macrostructures of vein filling on the order of ore body, three major mineralization stages, called stage I, stage II, and stage III from earliest to latest, are distinguished by major tectonic breaks as mentioned in this paper.
Abstract: Concepts on hypogene mineral zoning, mineral association, mineral paragenesis, and mineralization stage relating to macrostructures of vein filling in ore veins are briefly discussed. As an example of plutonic ore vein, macrostructures of vein filling of plutonic tungsten-tin-copper vein at the Otani mine, Kyoto Prefecture, Japan, one of representatives of plutonic tungsten-tin veins related genetically to granitoid of Late Cretaceous in-the Inner zone of Southwest Japan, are examined. Based on macrostructures of vein filling on the order of ore body, three major mineralization stages, called stage I, stage II, and stage III from earliest to latest, are distinguished by major tectonic breaks. Sequence of mineralization, characteristic features of each mineralization stage, and variations of filling temperature and salinity ranges of fluid inclusions in minerals from stage I to stage III are summarized.
05 Sep 1982-The Journal of the Japanese Association of Mineralogists,Petrologists and Economic Geologists
TL;DR: In the Janggun lead-zinc-silver ores, bournonite occurs as anhedral grains up to 2mm long, closely associated with galena, minerals of the tetrahedrite-freibergite series, boulangerite, sphalerite, pyrite and rhodochrosite as mentioned in this paper.
Abstract: In the Janggun lead-zinc-silver ores, bournonite occurs as anhedral grains up to 2mm long, closely associated with galena, minerals of the tetrahedrite-freibergite series, boulangerite, sphalerite, pyrite and rhodochrosite. The bournonite, though minor or trace in amount, tends to occur in the peripheries of the ore pipe. In reflected light, it is light greyish white in colour with greenish tints and exhibits weak bireflectance and distinct anisotropism without any internal reflections. Occasionally, lamellar twinning on {110} plane may be observed. Reflectance: Rmax=37.5, Rmin=33.8 percent at a light with wavelength of 580 nm, and VHN: 175-198kg/mm2 at a 50-g load. The chemical composition on the average from 15 spot analyses by electron microprobe for 5 grains is, Pb 43.3, Sb 24.4, Zn 0.0, Cu 12.9, S 19.7, sum 100.3 (all in weight percent); the corresponding empirical formula on the basis of S=3 is, Cu1.00 Pb1.03 Sb0.99 S3, which is close to the ideal formula CuPbSbS3. The strongest reflections on the X-ray diffraction patterns are; 3.90 A (8) (002), 2.97 A (4) (220), 2.73 A (10) (130), 2.67 A (4) (212), 2.59 A (5) (310), 1.766 A (6) (332), the patterns are identical with those of literature, and in harmony with the space group _??_-Pn 21m. This mineral is considered to have been formed at the latest stage of hydrothermal lead-zinc-silver mineralization. At the beginning of this paper, geologic environments of the ore deposits are briefly described.