Ore Elements and Minerals in the Sublimates of Alaid Volcano, Kuril Island Arc

Abstract

This paper is concerned with sublimates sampled in 2013–2020 in the near-crater zone and on the slopes of Alaid Volcano situated in the Kuril island arc. It was found that the near-crater zone contains native metals confined to zones of acidic leaching where the original lavas and tuffs have been transformed into opal-like rocks or rocks that are sharply enriched in hydroxides of trivalent iron. These zones were found to contain native gold, palladium, silver, chrome, copper, zinc and alloys of gold and palladium, copper and zinc, copper and tungsten. The mineral nomenclature in sublimates on the Alaid slopes is broader, while the temperature of their generation is lower. The ore minerals are dominated by copper-containing ones, and sublimates have been found with vanadium-containing minerals that belong to water-containing oxides and to silicates of vanadium. We have identified two genetic types of slope sublimates: (1) minerals that have crystallized from hydrothermal or vapor-hydrothermal solutions near vents of near-surface fumaroles and (2) copper and ferrous colloform formations that were generated by settling from colloidal solutions in shallow water of drying reservoirs, including small and large pools.