Abstract
This is a study on the mineral compositions, SK numbers of refractoriness and the genesis of the clay mineral deposits in Cheonnam Province and Handong area. 1. Jindo kaolin deposits: Chief clay minerals of the deposits are kaolinite, quartz and alunite. The SK number of the ore is from $34^+$(the highest) to 27(the lowest). On the genesis of the deposits some geologists believe that the deposits were formed by the alteration of the siliceous tuff. But the deposits seems to be formed by the hydrothermal alteration of the rhyolite lava beds. This area is formed by alternative beds of tuff; and kaoline deposits. 2. Hadong area: Chief mineralogy of Hadong kaolin area is $10{\AA}$ halloysite and kaolinite. The SK number of some of the ore is up to $36^+$. The theoretic SK number of kaolinitic composition is 35. So one of the highest alumina minerals of gibbsite is formed in the ores of $36^+$ SK numbers. 3. Hampyong kaolin deposits: Most of kaolin has black color. The chief minerals are kaolinite, quartz and muscovite. Some of the kaoline contains rutile crystals. SK number ranges from 30 to 17. The kaolin deposit is formed by the transported sedimentation in lower part of the seashore. 4. Jangsan kaoline deposits: Chief minerals of the kaolin is kaolinite, quartz and muscovite. Some kaoline contains small crystals of pyrite. This area consists almost of the tuffs. Kaolin deposits also would be formed by the alteration of the tuffs. 5. Nohwado pyrophyllite deposits: Quartz and pyrophyllite are chief minerals. SK number of the ore ranges from 32 to 30. The pyrophyllite deposits would be formed by the hydrothermal alteration of the rhyolitic lava beds. This area consists of alterative beds of tuffs and rhyolitic lavas. 6. Songsuk pyrophyllite deposits: Chief minerals are quartz, kaolinite, pyrophyllite and iron oxides. In the pyrophyllite deposits egg-like inclusions of diaspore and kaolinite in composition. This area almost consists of tuffs. Several faults are developed and along the fault the tuff would begin to alter to pyrophyllite and some parts to diaspore and kaolinite nodules by the acts of hydrothermal solution.
