Abstract: Sedimentology and Hydrocarbon Habitat of the Submarine-fan Deposits of the Levoca Basin (Centrocarpathian Paleogene, Slovakia)

SOTAK, JAN*, JULIA KOTULOVA, PAVEL PITONAK, JAN SPISIAK, JULIUS MAGYAR, RUDOLF RUDINEC

Levoca Basin belongs to the forearc system of the Central Carpathian Paleogene. The basin history consists of: Upper Eocene - initial tectonic subsidence with high accumulation rate of "synrift" deposits (up to 3500 m of the Sambron Beds); subsiding system gained an asymmetric configuration due to trenchward tilting and peripheral antithetic faulting (Poprad Depression); Lower Oligocene - post-rift relaxation with landward deepening and shifting of basin axis (underfilled basin); Upper Oligocene - flexural loading under high amount of the deep sea fan deposits, which enlarged the total subsidence up to 6 km of burial depth; Lower Miocene - subduction-related shortening (NE-SW), which led to inversion and uplift; the northern side of the basin was attached by fold-and-thrust tectonics and transpressional deformation. The Paleogene basin sequence has poor- to fair-quality of source rocks (TOC greater than or equal to 0.5%). Maturity of OM ranges from initial stage of HCs generation (central zone) up to relict stage of HCs generation (Sambron zone). Distribution of n-alkanes gives evidence about predominance of terrigenous OM or mixture of marine/terrestrial OM. Paleogene rock extracts display a good correlation with scarce tapered oils. Oil generation in the basinal deposits is also noticeable from the presence of solid bitumens and HC-rich fluid inclusions. Both of them point to overpressure conditions during HC generation and migration. Potential HC traps can be expected in porous sedimentary members (scarp breccias), in basement highs and structural environs related to wrench tectonics.