On Mineralogenesis Appeared in the Main Lodes of the Nakase Mine, Hyôgo Prefecture, Japan.

The ore deposited in this mine are naturally considered to have been produced through certain processes during four main periods denoted as P I, P II, P III, and P IV representing respectively a different sort of mineralization. The main lodes containing gold, silver, and antimony ores are comprised principally in those produced in P III correlated to Plio-Pleistocene, being furthermore subdivided into S 1 and S 2 in stage. Twenty five kinds of ore minerals have so far been described, among which some are found included commonly in all of the lodes formed in each period and the others only in those originated during specific periods. To be noted is that the main lodes representing P III have been excavated along the main gallery, revealing a sort of distorted échelon-like structure in their distribution. Veinlets composing this kind of the lodes have elaborately been scrutinized on their polished specimens and thin sections principally under the microscope so as to establish the mineralogenetic sequence. As was expected, the results obtained seem too complicated to be put in good order. It however is proven to be valid that variation of the mineral-izer in property with time is evidently recognized either as decrease of arsenic or as increase of antimony in the lodes produced at S 1 and S 2 stages, while variation in mineralic constituents is recognizable in the earlier to later veinlets as is shown in such sequence as arsenopyrite-berthierite-freibergite-stibnite. Each lode revealing discrepancy in arrangement is mineralogically somewhat different from one another, whereas a single lode indicates almost no vertical variation resulted from difference in temperature of mineralization and in mineral assemblage. It thus follows that the lodes under consideration might have been deposited from low-temperature hydrothermal solution displaying no remarkable difference in property on each level. On the other hand it is also to be taken into account that variation of property of the ascending solution might have taken place with time or with characteristics of fissures and that country rocks embracing the lodes might have provided the spaces for deposition of ores without any notice-able effects

XAFS analyses of molten metal fluorides

X-ray absorption fine structure studies of molten metal fluorides containing the materials related to nuclear engineering are intensively summarized. By using XAFS spectra data of divalent and trivalent cation metal fluorides in molten state which have been collected by authors’ group for a few years, local structure have been extracted and discussed systematically in conjunction with other spectroscopic studies and numerical calculations. In molten divalent fluorides, tetrahedral coordination of fluorides around a cation is predominant. In the case of pure molten trivalent fluorides, structure with more than 6-coordination has been suggested in some cases, but octahedral coordination structure is much stabilized at heavier rare earth metal fluorides. By mixing with alkali metal fluorides, it is a general trend that inter-ionic distances keep constant, but coordination number of fluorides decreases. In experimental chapter, all the details of sample preparation, furnace installation, X-ray optics setups and data analyses procedures are explained. Finally, future expectations of XAFS technique are also suggested

Notes on the Ore Deposits of the Nakase Mine in Hyôgo Prefecture, Japan.

The Nakase Mine is situated at Yoshii, Sekinomiya-chô, Yabu-gun, Hyôgo Prefecture, Japan and its surroundings are geologically consisted of the Sangun metamorphics, serpentinite, granitic rocks, Manju volcanics, Kinosaki Subgroup belonging to Hokutan Group, Saruo-no-taki dikes including micro- quartz-diorite, Tentaki lavas belonging to Daisen volcanics, and basaltic dike in descending sequence. It seems to be remarked that the ore bodies of this mine are found deposited as lodes mainly in the metamorphics as well as in the Manju volcanics, micro-quartz-diorite, and rather scarcely in serpentinite or others but are cut in particular by basaltic dikes. The ores concerned are naturally assumed to have been produced through certain processes in four main periods. such as Period I, Period II, Period III, and Period IV. The fact of importance is that activities of porphyrite and breccia dikes are evidently recognizable intervening between Period II and Period III. Certain minerals selected out from more than twenty-eight specimens are röntgenometrically scrutiniz-ed, whereas horizontal or vertical variations in their assemblages as well as in genetic relation are not conspicuously determinable within each lode. It however results in at least that the main lodes originated in Period III, that is the veins containing gold, silver, and antimony ores, especially seem to be grouped into an ordinary category of epithermal de-posit

Mineral Springs in the Southern Part of Ōsaka Prefecture

The analytical data obtained after the appointed rule by some authors including the present writer for more than twenty springs situating within the geologically characteristic area in the southern part of Ōsaka Prefecture and the relations of specific constituents such as carbon dioxide and hydrogen sulfide to their sources have been disputed with respect to the geologic environments.今村外治教授退官記念特集

On Prehnite and Some Others from the Takase Mine, Okayama Prefecture

The vein-like lenticular mass composed of prehnite and some others have been found intervening within serpentinite in the Takase mine famous for production of the chromite ores on an industrial scale and studied somewhat genetically with respect to so-called "rodingite". In addition, thermal behaviors of prehnite and garnet have been pursued for inspection of their genesis or interrelations.今村外治教授退官記念特集