Nuttakan Wongfun (ETH Zürich, Switzerland)
"Weathering of granite rock in the Damma glacier forefield"


Mobilization of nutrients from rock through weathering processes plays a crucial role to overcome the limitation of nutrient in the glacier forefield. Microorganisms and plants modify their local environment by various exudates including cyanide, which is a very important agent during the initial period of colonization and soil formation. We study the weathering mechanisms of primary rock-forming minerals. Rock and weathered stream sediments were obtained from the Damma glacier area. Qualitative conclusions on different water regimes result from variations in hydrological factors, such as water availability and degree of physical protection. The mineralogical characterization of the sediments from the forefield also revealed trends in physical weathering processes and consequently in the availability of nutrients. The study of dissolution experiments under controlled conditions showed the presence of cyanide caused a suppression of iron in comparison to cyanide-free conditions.