Abstract: Sequence Stratigraphic Framework of Paleogene - Lower Miocene Strata, Southern Carpathians Foredeep, Romania

RYER, MIHAELA STEFAN

The Southern Carpathians foredeep accumulated up to 3000 m of siliciclastic strata during Paleogene-E.Miocene time. Outcrop, well log, biostratigraphic and seismic data were used to divide this section into five depositional sequences. Sequence boundaries were interpreted on the basis of several criteria: 1) fluvial, valley-fill deposits on the northern basin margin, 2) turbidite sands overlying pelagic shale in the basin center, 3) faunal discontinuity events, and 4) seismic reflection terminations.

Lowstand and transgressive systems tracts are the major components of the basin fill. Highstand deposits represent only a minor component. The character of the lowstand turbidites changed through time. In the older sequences, they are represented by coarse-grained, highly channelized systems fed by alluvial fans or fan deltas. In the younger sequences, they include composite systems consisting of basin floor fans overlain by channel-levee complexes. This suggests changes in basin configuration, from a basin with a narrow shelf and steep slope, to a basin with a broader shelf and gentler slope, which allowed development of mature deltaic systems. The transgressive systems tracts are laterally extensive and relatively thick; highstand systems tract deposits were preserved only for the youngest sequence and are thin.

The deep-water turbidite sands represent good reservoirs; associated transgressive systems tract constitute good potential source rocks. The proposed stratigraphic framework indicates the presence of new hydrocarbon exploration plays in the Southern Carpathians foredeep.

AAPG Search and Discovery Article #90942©1997 AAPG International Conference and Exhibition, Vienna, Austria