Mid-Mesozoic syn-rift turbidite systems: controls and predictions

Abstract

Submarine syn-rift deposits are commonly characterized by turbiditic assemblages. The sedimentary processes and the nature and organization of the depositional systems are governed by a variety of partly interrelated factors such as regional and local tectonic style, subsidence rate, sedimentation rate, compaction, composition of source terrain, base and sea level, rate of sea-level change, climate, inclination and length of slopes, and depth and morphology of receiving basin. A major Mesozoic rift event in the northern North Sea — North Atlantic realm was initiated in mid-to-late Jurassic times, climaxed in the Early-Middle Volgian, and gradually abated in the early Cretaceous. The tectonic leitmotif was the tilted fault block. A variety of syn-rift turbidite systems was deposited in the basins formed over the hangingwall blocks. A number of examples have been selected to illustrate the great variation and difficulties of sediment-body correlation in these systems. Their main similarities and differences are highlighted and related to sea-level stand, tectonic style, provenance area and sedimentary processes. The relative effects of the governing factors are then isolated, and a number of predictions made concerning the facies types and architecture of clastic submarine syn-rift sequences in general. Predictions are strongly improved by precise dating and time-stratigraphic correlation within and between systems.