Eocene siliciclastic continental shelf sedimentation in the Southern Bight North Sea, Belgium

Eocene sedimentation in the Southern Bight of the intracratonic North Sea Basin is determined by its ramp margin setting. Lithofacies analysis of siliciclastic shallow marine sediments enables reconstruction of sedimentation model in relation to relative sea level changes. Two major sedimentary cycles composed of sequences of metric to decametric thickness can be discerned. The lower transgressive/regressive cycle evidences 3 sedimentary environments. Lowermost Eocene sediment units are mainly clayey, display an overall fining upward trend an are deposited on a mud shelf. A delta prograding out on the continental shelf deposits middle to upper Lower Eocene units, gradually becoming more sandy. Middle Eocene sediments are mainly sandy, contain calcarenite horizons, coarsen upward and are predominantly of tidal and lagoonal origin. The upper cycle is composed of only 2 sedimentary environments. Lower Upper Eocene sediment packages consist of a succession of 4 gradually fining upward sandy to clayey sediment units of distal (pro)delta origin, while the Uppermost Eocene has a more sandy character and is of tidal sand flat origin. The general sedimentation is that of an advancing and retreating mainly deltaic sedimentation system, consisting of onlapping and shallowing upward sediment units, gradually infilling the Southern Bight of the North Sea Basin due to constant sediment supply of southern origin