The Banská Štiavnica ore district: relationship between metallogenetic processes and the geological evolution of a stratovolcano

Abstract

The BanskaStiavnica ore district is in the central zone of the largest stratovolcano in the Central Slovakia Neogene Volcanic Field, which is situated at the inner side of the Carpathian arc over the Hercynian basement with the Late Paleozoic and Mesozoic sedimentary cover. Volcanic rocks of the High-K orogenic suite are of the Badenian through Pannonian age (16.5–8.5 Ma). Their petrogenesis is closely related to subduction of flysch belt oceanic basement underneath the advancing Carpathian arc and to back-arc extension processes. The stratovolcano includes a large caldera 20 km in diameter and a late-stage resurgent horst in its centre, exposing a basement and extensive subvolcanic intrusive complex. The following stages have been recognized in the evolution of the stratovolcano: (1) formation of a large pyroxene/hornblende-pyroxene andesite stratovolcano; (2) denudation, emplacement of a diorite intrusion; (3) emplacement of a large granodiorite bell-jar pluton within the basement; (4) emplacement of granodiorite/quartz-diorite porphyry stocks and dyke clusters around the pluton; (5) caldera subsidence and its filling by biotite-hornblende andesite volcanics, emplacement of quartz-diorite porphyry sills and dykes at the subvolcanic level; (6) renewed activity of andesites from dispersed centres on slopes of the volcano; (7) uplift of a resurgent horst accompanied by rhyolite volcanics and granite porphyry dykes.