Chemical Constituents in the Surface Snow in Mizuho Plateau

Abstract

Chemical features and profiles of the ice sheet in Mizuho Plateau have been revealed by means of newly developed analytical techniques such as atomic absorption spectrophotometry, neutron activation method and isotope dilution mass spectrometry. The chemical concentration is as low as ppb level even for the major components, Na, K, Mg and Ca, and its distribution is homogeneous in the surface sheet but shows much vertical complexity. Silicate dusts which functioned as the condensation nuclei for the formation of snow crystal in the upper atmosphere and which were captured by snow fall process are poor, while sea salts account for more than 90per cent of the total weight of components. Annual accumulation of chemical components, μg/(cm)^2,is 0.1 for silicate dusts and 0.40,0.03,0.1 and 0.06 for Na, K, Mg and Ca originated from the latter source. Annual accumulation of Hg and Pb is at the level of 0.1 and 1.5 ng/(cm)^2 at the present time while 0.02 and 0.3ng/(cm)^2 in ancient times