Volcanism and the Geochemistry of Soil and Vegetation in Kamchatka. Part 1. Some Geochemical Features of Near-Surface Volcanic Ashes

The common geochemical features of Kamchatka near-surface ashes (ashes that underlie surface organogenic soil horizons) include their depletion in most chemical elements compared with the average figures for volcanic rocks of the same composition and their relative enrichment in a narrow range of elements, mostly those which are typomorphic for basic rocks (Р, Mg, V, Cr, Cu, Zn, Zr, and Sb). Viewed upon the background of small variations in the concentrations of chemical elements in ashes from different areas in the peninsula, the range of their dominant elements is controlled by their petrochemical composition. The vigorous activity of Kamchatka’s Northern Group of Volcanoes has produced relatively higher concentrations of mobile forms of elements in the near-surface ashes of the Northern Province compared with the ashes found in the southern part of the peninsula.