The Heavy Minerals of the Takashima Coal Field, Kyushu, Japan

Abstract

The present paper deals with the heavy minerals observed in the sandstones of the Takashima Coal Field (Paleogene), Kyushu, giving weight percentage, kinds of heavy minerals, and character of distribution frequencies. Statistical methods are used to check the differences in heavy mineral frequen ties in each formation.
1) The weight percentage of the heavy minerals is the least (0.1%±) in the sandstones of the Hashima formation, and is the most (1-5%±) in those of the Koyaki and Iojima formations.
2) The kinds of the heavy minerals are : zircon (colorless, purple, brown), garnet (colorless, brown, pink), tourmaline (brown, green, blue, gray, etc.), epidote, zoisite, titanite, rutile, muscovite, biotite (brown, reddish brown), a green mica-like mineral, iron opaques (magnetite, ilmenite, hematite, limonite, pyrite, etc.), green hornblende (rare), pyroxene (rare), monazite (rare), glauconite, anatase, a chlorite-like mineral, and carbonates.
3) The character of the heavy mineral frequencies in each formation is : Iojima formation (upper member) : epidote and titanite, rare; colorless zircon, purple zircon, garnet, tourmaline and rutile, abundant.
Iojima formation (lower member) : epidote and titanite, abundant ; colorless zircon and brown tourmaline, rare.
Okinoshima formation : epidote and titanite, rare ; colorless garnet, biotite and anatase, abundant.
Hashima formation : colorless zircon, very abundant ; purple zircon, rutile and iron opaques, abundant ; epidote and titanite, rare.
Futagojima formation (upper member) : epidote and titanite, rare ; colorless zircon, brown tourmaline and biotite, abundant.
Futagojima formation (lower member) : epidote and titanite, common; colorless garnet, abundant.
Koyaki formation : epidote and titanite, very abundant ; biotite, abundant ; glauconite, rare.