Investigation report of the San Chong and Tan Song halloysite deposits, San Chong Gun, Kyongsang Namdo, Korea
Kim, J.H.; Kim, D.H.
Chigil Kwangsan Chosa Yon'gu Pogo = Bulletin - Geological Survey of Korea 7: 67-88
1964
Document Number: 634407
Clay deposits containing halloysite are associated with a large mass of anorthosite cut by basic and acidic dikes. The dominant rock in this area, in southernmost south Korea, appears to be labradorite with some uralite and tremolite and exhibiting gneissoid texture. The area was originally mapped as Cretaceous gabbro in Precambrian granite-gneiss terrain. These rocks are coarse- to medium-grained, showing evidence of cataclasis. The border facies is finer grained and more mafic than the core and is schistose rather than gneissoid. These facts conform with the characteristics of other world occurrences of anorthosite intrusives in the Precambrian. To the north of the area, the anorthosite is overlain by the basal conglomerate of the upper Jurassic Naktong series, indicating a pre-upper Jurassic age for the anorthosite. Deposits at San Chong and Tan Song are described. The relatively humid, mild climate, ideal topography, and silica-free monomineral parent rock favor the formation of halloysite clay by podzolization. The deposits can therefore be described as the chemical weathering products of anorthosite. Results of chemical analysis are given in tables, in English.