NEMCOK, MICHAL, Dionyz Stur Institute of Geology, Bratislava, Czechoslovakia; and D. G. NEESE, Maxus Energy Corporation, Dallas, TX

ABSTRACT: Development of the Central Carpathian Paleogene Basin, West Carpathians, Slovakia

The central Carpathian Paleogene basin, corresponding to one of the regions of Slovakia having a hydrocarbon potential, forms part of the Carpathian system, which developed on the northern margin of Tethys during the oblique collision of Africa and Europe. In the west Carpathians, synorogenic sediments, derived from the rising orogene, comprise an up to 3.5-km-thick sequence of Middle Eocene to Early Oligocene clastics. Flysch-type sediments dominate and are locally cut by canyon-focused submarine fans.

The morphology of the floor of the central Carpathian Paleogene basin developed during the Albian and Maastrichtian, in response to pre-Senonian nappe emplacement in the inner Carpathians and Late Cretaceous thrusting in the Pieniny Klippen belt; the latter corresponds to the collision zone between the central Carpathian block and the margin of stable Europe. By the end of the Cretaceous, the inner Carpathians formed an emergent orogenic

belt, providing a southern source for the sedimentary fill of the central Carpathian Paleogene basin. To the north, this basin was bounded by the Pieniny Klippen belt, forming at that time an irregular chain of islands, upheld by compressionally deformed pre-Tertiary rocks. Uplift of this northern, effective barrier may explain the development of the central Carpathian Paleogene current system.

Senonian shortening was subparallel to the present strike of the Pieniny Klippen belt. During the Paleogene and Miocene, shortening changed to a northern or northeastern direction. Differential shortening gave rise to the development of major strike-slip zones and numerous strike-slip faults that accommodated differential motion of thrust slices along the orogenic front. The northern, frontal portions of the basin were shortened by thrusting, whereas its basinal and proximal parts were affected by contemporaneous transtensional strike-slip faulting. Paleogene uplift of the frontal part of the evolving mountain belt is recorded by high-slump activity in areas of flysch deposition. A minimum of 2 km of sediments, including a final regressive phase, are missing from the basin due to Mioc ne erosion. At present, only structural remnants of the ancestral Paleogene basin are preserved.

AAPG Search and Discovery Article #90990©1993 AAPG International Conference and Exhibition, The Hague, Netherlands, October 17-20, 1993.