Provenance study of detrital garnets and rutiles from basaltic pyroclastic rocks of Southern Slovakia (Western Carpathians)

Abstract

AbstractDetrital garnets and rutiles have been recovered from basaltic pyroclastic rocks in the northern part of the Pannonian Basin and characterized using electron probe microanalysis and imaging. All garnets are dominated by the almandine component, except for one sample dominated by spessartine. A total of three garnet groups have been distinguished according to the increased contents of grossular (Group I), pyrope (Group II) and spessartine components (Group III). Compositions of the group I and II garnets with fluctuating Ca- and relatively low Mg contents are consistent with low- to medium-grade metasediments and/or metabasites. Locally increased Mg contents could indicate higherP–Tmetamorphic overprint. The dominantly metamorphic origin of the Group I and II garnets (composed of >99 % of samples) is also corroborated by chlorite, tourmaline, staurolite, ilmenite and andalusite inclusions. Spessartine-rich garnets (Group III composed of <1 % of samples) could be genetically linked with granitoids. Detrital rutiles invariably plot within the field of metasediments metamorphosed under amphibolite-facies conditions. Possible proximal (subjacent basement sampled by ascending lava) or distal sources (catchment sediments from uplifted Central Carpathian basement) of heavy mineral assemblages are discussed.