GALLOWAY, W. E., XIJIN LIU, and B. J. SLOAN, The University of Texas at Austin, Austin, TX

ABSTRACT: Tectonic Signature in the Cenozoic Sequence Stratigraphic and Depositional Framework of the North Sea Basin

The Danian-through-Miocene fill of the North Sea basin consists of four tectonosequences that record the regional evolution of the basin and its surrounding source terrains. The tectonosequences, in turn, contain stratigraphic sequences that record at least 15 depositional episodes. Each episode, a regionally significant pulse of basin infilling, deposited an array of deltaic, shorezone, shelf, and slope/basin depositional systems. The resultant stratigraphic sequences are bounded by condensed sections and/or erosion surfaces. The late Paleocene tectonosequence includes six depositional episodes and was initiated by differential structural movement coupled with source-area uplift. Proximal delta-fed submarine aprons of the Maureen and Andrew episodes were subsequently overridden by th Forties/Dornoch braid-delta system. Progradation was, in part, forced by tectonic uplift on the western basin margin. Widespread source-area and basin-margin collapse and foundering terminated in the Paleocene with regional flooding and deposition of the early Eocene Balder condensed section. Mass-wasting of the relict shelf margins, triggered by seismic shocks and ongoing crustal readjustment along rift-related fault trends, resedimented Paleocene deposits as slump and turbidite lobes. The Eocene tectonosequence began with the Frigg depositional episode. A combination
of steep shelf gradient and high marine energy flux bypassed shelf sediment to the Viking trough. Subsequently, four shelf progradational episodes terminated with pulsed latest Eocene shelf offlap driven by relative sea level fall. Oligocene and Miocene tectonosequences encompass four
depositional episodes. Sediments deposited in deep shelf and basin settings were increasingly reworked by geostrophic currents, culminating in deposition of a large late Miocene contourite drift complex.

AAPG Search and Discovery Article #90987©1993 AAPG Annual Convention, New Orleans, Louisiana, April 25-28, 1993.