• Journal of the Mineralogical Society of Korea
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• v.25 no.3
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• pp.131-141
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• 2012

The guano formed from the bat excrement in a cave contains various sulfate and phosphate minerals formed from the reaction of bat excrement with surrounding rocks and clastic minerals. Therefore, the mineral compositions in the guano provide basic informations on the geochemical environments affecting mineral formation in a cave. This study was conducted to study the mineral compositions of guano and the factors affecting those compositions by comparing mineralogical and chemical compositions in three different limestone caves in Korea. The guano samples in Gossi Cave contain detrital minerals such as illite, quartz and feldspar and relatively large amount of gypsum. The contents of gypsum increase with increasing depth, which is different from the samples collected in other caves. The samples collected from Baekryong Cave have the similar mineral compositions to those in Gossi Cave, but they also contain additional kaolinite and very small amount of gypsum. The samples in Sungryu Cave have similar mineralogical compositions to those in Gossi Cave, but contian bassanite instead of gypsum. The mineralogical compositions are well correlated with the chemical compositions of guano. The mineral compositions indicate that, in Gossi Cave, the minerals were formed by the reaction of large amount of bat excrement with surrounding rocks in high humidity condition or in the condition of frequent floods. In the case of Sungryu Cave, bassanite which can be formed in a dry condition indicates that minerals were formed in a relatively low humidity condition.