Amygdaloidal graphite in pottery stone from Tobe District, Ehime Prefecture

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Authors:Minakawa, Tetsuo; Wada, Hideki; Tsuzuki, Yoshiro
Volume Title:Ganseki Kobutsu Kosho Gakkai-Shi Journal of the Japanese Association of Mineralogists, Petrologists and Economic Geologists
Source:Ganseki Kobutsu Kosho Gakkai-Shi = Journal of the Japanese Association of Mineralogists, Petrologists and Economic Geologists, 75(5), p.139-145. Publisher: Nippon Ganseki Kobutsu Kosho Gakkai, c/o: Tohoku Daigaku Rigakubu, Sendai, Japan. ISSN: 0021-4825
Publication Date:1980
Note:In Japanese with English summary. 23 refs.; illus. incl. table, geol. sketch map
Summary:Andesitic rocks, which were intruded into or flowed over crystalline schists of the Sanbagawa metamorphic belt and sediments of the Palaeogene Kuma group in the Tobe district, were altered to pottery stone by hydrothermal solution in many places. The pottery stone with graphite in Koboshi deposit is composed of quartz and a mica clay mineral (1M polytype) and sometimes kaolinite. Graphite usually occurs in the middle horizon of the deposit. Amygdaloidal graphite aggregates up to 1 cm in diameter fill pores in the pottery stone usually associated with mica clay mineral. Some pores are filled by mica clay mineral (1M polytype), tosudite or mixture of these minerals without graphite, and vacant pores are often observed. Constituent graphite crystals are tabular and 5-50 mu m in size. The XRD peaks are very sharp. The 13C/12C ratio of the graphite is 21.1per mille (PDB). It is suggested that the graphite was formed by oxidation of hydrocarbons in an ascending hydrothermal solution. [M.Ak.]
Subjects:C-13/C-12; Carbon; Cenozoic; Graphite; Isotopes; Metamorphic belts; Metasomatism; Minerals; Native elements; Paleogene; Petrology; Stable isotopes; Tertiary; Asia; Ehime Japan; Far East; Japan; Shikoku; Amygdaloidal texture; Kuma Group; Native elements and alloys; Tobe
Coordinates:N320000 N340000 E1340000 E1320000
Abstract Numbers:84M/0524
Record ID:1981014407
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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