1999 Volume 108 Issue 1 Pages 1-17
Many tafoni and gnammas occur on the granite tors on Mt. Doeg-sung, Korea. The influence of rock properties on tafoni and gnammas development was examined based on (1) field investigations of tafoni morphology and (2) field measurements for rock hardness and moisture contents of the tors. Field evidence is summarized as follows. (1) Tafoni are classified into three types : sidewall tafoni, basal tafoni, and ceiling tafoni. (2) Directional data for sidewall- and basal-tafoni reveal no tendency for tafoni opening to face a particular direction. (3) The presence of salts such as gypsum and littered rock fragments on tafoni and gnammas floor suggest that salt weathering plays an important role in tafoni- and gnammas-development, and they are active under current environmental conditions. (4) Measurements of rock properties of tors show that tafoni and gnammas occur on the weathered portion of tors with weak rock-strength and high moisture content.