Structural, biostratigraphic and petrographic evaluation of the Upper Cretaceous red marlstones and underlying granitoids from the borehole HPJ-1 Ja?ter near Hlohovec (Pova?sky Inovec Mts., Slovakia)

摘要

The article provides the first results of analyses of the core material from the borehole HPJ-1 Ja?ter, located north of Hlohovec in the southern Pova?sky 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.