• Economic and Environmental Geology
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• v.49 no.1
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• pp.1-11
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• 2016

Chrysotile is well known as a fibrous mineral in serpentinite by the previous studies in S. Korea. Previous studies in other countries showed that antigorite also occurred as asbestiform and harmful to humans. Therefore, the objective of this study was to investigate types and characteristics of fibrous serpentine minerals occurred in serpentinite in Hongseong, Chungnam and Gapyeong, Gyeonggi in S. Korea. XRD, SEM-EDS, PLM and EPMA mapping analyses were used to examine the occurrence and formation mechanism of serpentine minerals. Serpentinization partially occurred in amphibole-schist and calc-schist at two study sites, Hongseong, Chungnam and Gapyeong, Gyeonggi, respectively. Both chrysotile and antigorite occurred as a fibrous mineral at Hongseong site, but chrysotile occurred as a fibrous mineral at Gapyeong site. Based on PLM analysis with dispersion staining, the chrysotile was observed horizontally magenta and vertically blue colors. The antigorite appeared as horizontally gold to golden magenta and vertically blue magenta colors under central stop dispersion staining objective(DSO). PLM and SEM analyses showed the fibrous minerals were formed from plate form of serpentine minerals or by hydrothermal alternation of primary minerals. The EPMA mapping showed that Mg contents in chrysotile is relatively higher than that in antigorite while Si and O contents in antigorite is higher than them in chrysotile. However, more studies are necessary to know the exact variation in chemical composition of chrysotile and antigorite. These results indicate that even though asbestiform antigorite found associated with asbestos chrysotile in serpentinites, the fibrous antigorite can be distinguished from chrysotile by different dispersion staining colors.