The Banska Stiavnica ore district: relationship between metallogenetic processes and the geological evolution of a stratovolcano

摘要

The Banska Stiavnica ore district is in the centralzone of the largest stratovolcano in the Central Slovakia NeogeneVolcanic Field, which is situated at the inner side of theCarpathian arc over the Hercynian basement with the LatePaleozoic and Mesozoic sedimentary cover. Volcanic rocks of theHigh-K orogenic suite are of the Badenian through Pannonian age(16.5-8.5 Ma). Their petrogenesis is closely related to subductionof flysch belt oceanic basement underneath the advancingCarpathian arc and to back-arc extension process. Thestratovolcano includes a large caldera 20 km in diameter and alate-stage resurgent horst in its centre, exposing a basement andextensive subvolcanic intrusive complex. The following stageshave been recognized in the evolution of the stratovolcano: (1)formation of a large pyroxene/hornblende-pyroxene andesitestratovolcano; (2) denudation, emplacement of a diorite intrusion;(3) emplacement of a large granodiorite bell-jar pluton within thebasement; (4) emplacement of granodiorite/quartz-diorite porphyrystocks and dyke clusters around the pluton; (5) caldera subsidenceand its filling by biotite-hornblende andesite volcanics,emplacement of quartz-diorite porphyry sills and dykes at thesubvolcanic level; (6) renewed activity of andesites from dispersedcentres on slopes of the volcano; (7) uplift of a resurgent horstaccompanied by rhyolite volcanics and granite porphyry dykes.