Abstract |
In the Fukue Island, Nagasaki Prefecture, several pyrophyllite deposits, mostly accompanying diaspore, are distributed. This paper describes the deposits of the Tao mine, which are situated in the sou...thern part of the island. On the margin of granite porphyry, which intrudes sandstone and shale of the Miocene Goto group, Ishiharayama deposit is developed, and the ore is composed mainly of pyrophyllite, quartz and kaolin. Diaspore-rich small ore bodies are also found in the deposit in lenticular or irregularmass. They contain diaspore, pyrophyllite, kaolin, rutile, and an interstratified mixture of mica clay minerals with 27.6 A reflection, being partly accompanied by pinkishviolet dumortierite and blueish corundum. Dickite is found as shells of the dispore ores. The deposit is surrounded by an alteration aureole, which is characterized by formation of sericite and chlorite. Miurayama, Matsushitayama and Osawayama deposits show nearly the same occurrence as Ishiharayama deposit. In Yokomine deposit, pyrophyllitization is developed in tuff-breccia and sandstone, being distant from granite porphyry.show more
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