Two types of noble metal mineralization in the Kaalamo massif (Karelia)

Abstract

Noble metal mineralization of the syngenetic (Southern Kaalamo) and epigenetic (Surisuo) types are defined in the Kaalamo massif. The ƩPt, Pd, Au content is as high as 0.9–1.1 g/t. Syngenetic mineralization started at the late magmatic stage (at around 800°C) gradually evolving to cease during the hydrothermal–metasomatic stage (<271°C). Epigenetic mineralization was formed at temperatures ranging from 500 to <230°C in zones of intense shear deformations and low-temperature metasomatosis during the collisional stage of the Svecofennian tectono-magmatic cycle (approximately 1.85 Ga ago). Taking into consideration the geological position of the Kaalamo massif in the Raakhe–Ladoga metallogenic zone with widely developed intense shear dislocations, the epigenetic mineralization type seems to be more promising with respect to noble metals.