Pelech O., Józsa Š., Kohút M., Plašienka D., Hók J. & Soták J., 2016: Structural, biostratigraphic and petrographic evaluation of the Upper Cretaceous red marlstones and underlying granitoids from the borehole HPJ-1 Jašter near Hlohovec (Považský Inovec Mts., Slovakia). Acta Geologica Slovaca, 8, 1, 27–42.

Structural, biostratigraphic and petrographic evaluation of the Upper Cretaceous red marlstones and underlying granitoids from the borehole HPJ-1 Jašter near Hlohovec (Považský Inovec Mts., Slovakia)

Ondrej Pelech¹, Štefan Józsa², Milan Kohút³, Dušan Plašienka², Jozef Hók² & Ján Soták^2,4,5

¹State Geological Institute of Dionýz Štúr, Mlynská dolina 1, 817 04 Bratislava, Slovakia; ondrej.pelech@geology.sk
²Department of Geology and Palaeontology, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynská dolina, Ilkovičova 6, 842 15 Bratislava, Slovakia
³Earth Science Institute of Slovak Academy of Sciences, Dúbravská cesta 9, P.O. Box 106, 840 05 Bratislava, Slovakia
⁴Earth Science Institute of Slovak Academy of Sciences, Ďumbierska 1, 974 01 Banská Bystrica, Slovakia
⁵Department of Geography, Faculty of Education, Catholic University, Hrabovská cesta 1, 034 01 Ružomberok, Slovakia

Abstract

The article provides the first results of analyses of the core material from the borehole HPJ-1 Jašter, located north of Hlohovec in the southern Považský Inovec Mts. (Western Carpathians, Slovakia). The main aim of the borehole was to determine the thickness and characteristics of sedimentary sequence of the Upper Cretaceous Horné Belice Group in a poorly exposed area and to reach its possible substratum. In the initial interval 0–45.8 m, the borehole penetrated deformed sequence of red and pink pelagic marly limestones and marlstones containing planktonic foraminifera. The drilled sediments are of the Late Cenomanian (45.5–41.5 m) and Middle Turonian – Santonian (41.5–34 m) age in the lower part of the sedimentary sequence. Stronger alteration and tectonic overprint of the uppermost interval (34–0 m) prevented a successful biostratigraphic age determination. The lower part of the borehole profile between 45.8–75.5 m is formed by pre-Alpine biotite granodiorites, which are separated from the overlying sedimentary sequence by a normal fault. Several possible interpretations of the tectonic position of the Upper Cretaceous complexes are discussed.

Key words: Western Carpathians, Tatricum, Horné Belice Group, Late Cretaceous, biostratigraphy, Cretaceous oceanic, red beds, granitoids

Manuscript received: 2015-12-18

Revised version accepted: 2016-03-21