Madzin J. & Plašienka D., 2022: Petrographic and heavy mineral analysis of the Upper Cretaceous – Paleocene turbiditic deposits of the Pupov Formation (Western Carpathians, Pieniny Klippen Belt, Terchová-Zázrivá area). Acta Geologica Slovaca, 14, 2, 115–130.

Petrographic and heavy mineral analysis of the Upper Cretaceous – Paleocene turbiditic deposits of the Pupov Formation (Western Carpathians, Pieniny Klippen Belt, Terchová-Zázrivá area)

Jozef Madzin¹ & Dušan Plašienka²

¹Earth Science Institute, Slovak Academy of Sciences, Ďumbierska 1, 974 11 Banská Bystrica, Slovakia; jozef.madzin@savba.sk
²Department of Geology and Paleontology, Faculty of Natural Sciences, Comenius University, Mlynská dolina, Ilkovičová 6, 942 15 Bratislava, Slovakia

Abstract

Provenance study of the Upper Cretaceous – Paleocene turbiditic deposits of the Pupov Formation with uncertain tectonic affiliation exposed in the Varín sector of the Pieniny Klippen Belt is presented. Petrographic and heavy mineral analyses including geochemistry of detrital Cr-spinels, tourmalines and garnets were carried out. The studied deposits include litho-quartzose to feldspatho-litho-quartzose sandstones, fine-grained conglomerates and pebbly mudstones. They contain mostly lithoclasts of low- to medium-grade metamorphic rocks, basic volcanites and carbonates. Impoverished heavy mineral assemblage includes ultrastable tourmaline, zircon, rutile accompanied by Cr-spinel and apatite. Garnets, exclusively of almandinic composition, are rare, except of one locality from pebbly mudstone where they dominate. Cr-spinels of harzburgitic peridotite composition derived from supra-subduction zones dominate over Cr-spinels of volcanic origin. Detrital tourmalines include besides schorlitic-dravitic tourmalines also subhedral to angular distinctly zoned tourmalines of schorlitic-dravitic and magnesiofoititic to foititic compositions with fine intergrowth with quartz and tourmalines possessing magnesiofoititic-foititic cores and schorlitic-dravitic rims. The primary source for the Cr-spinels and complexly zoned tourmalines appears to be in Meliata ophiolite-bearing complexes feeding flysch deposits in the original Fatric Zliechov Basin. After the Turonian emplacement of the Fatric nappe system beyond the Tatric edge, the exotics-bearing formations of the Klape Unit formed the source of ophiolitic detritus in foreland basins of the developing accretionary wedge. Based on the specific structural position, age, lithological composition and impoverished heavy mineral assemblage, the Pupov Formation could represent a part of the wedge-top Gosau-type basin system developed during the meso-Alpidic (Coniacian – Eocene) tectonic epoch.

Key words: Pieniny Klippen Belt, Gosau, Upper Cretaceous, Pupov Formation, heavy minerals, provenance

Manuskript doručený: 2022-09-20

Manuskript revidovaný: 2022-12-02