The space-time relationships between volcanic associations of different alkalinities: The Belogolovskii massif in Kamchatka’s Sredinnyi Range. Part 1. The geology, mineralogy, and petrology of volcanic rocks

Abstract

We proposed a geological and petrologic model for the generation of the Belogolovskii Late Pliocene to Early Pleistocene volcanic massif. We identified two petrochemical series of rocks with varying alkalinities, viz., normal and moderate. The evolution of volcanic products and the mineralogic composition of rocks of varying alkalinities provide evidence that the sources of parent magmas are spatially independent and reside at different depths. Crystallization differentiation is the leading process that is responsible for the generation of the initial melts that give rise to the range of rocks within a series. The evolution of the alkaline basaltic magma occurred stepwise, producing autonomous daughter melts with the following compositions: trachybasalt-trachyandesite-trachyte-trachyrhyolite and comendite. These melts were localized in inter-mediate magma chambers at different depths.