--> Abstract: Sequence Stratigraphy and Depositional Systems of the Paleocene Submarine Fans in the Central North Sea: The Evolution of a Shelf-to-Basin System, by B. C. Reinsborough and W. E. Galloway; #90990 (1993).

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REINSBOROUGH, BRIAN C., and WILLIAM E. GALLOWAY, University of Texas, Austin, TX

ABSTRACT: Sequence Stratigraphy and Depositional Systems of the Paleocene Submarine Fans in the Central North Sea: The Evolution of a Shelf-to-Basin System

Slope/basin depositional systems consist of combinations of facies, including slump lobes; chute, flute, and channel fills; mounded turbidite lobes; sheet turbidites; low-density turbidite sheets and fills; hemipelagic drapes; and contourite mounds. Specific facies associations are determined by the nature (point source or linear source) and caliber (volume, grain size, sand:mud) of sediment supply to the slope. The extensive well-log, seismic, and core database was used to dissect the stratal and facies architecture of the Andrew depositional system and characterize a logical evolution of the sand-rich shelf-to-basin depositional systems tract.

The Andrew consists of upper and lower depositional units

bounded by downlap terminations and high-gamma marker beds. The lower Andrew displays three distinct sand-rich lobes, delineated by isopach, sand percent, log motif, and seismic facies maps. Proximal, mounded, sand-rich units disperse into unchannelized sheet turbidites in the basin. No extensive incised submarine valleys feed this unit, which is characterized by coarsening and thickening-upward log responses and hummocky to discontinuous reflectors.

The upper Andrew downlaps the lower unit and a single, linear sediment source was centered in the Witch ground graben. The dispersal pattern and internal character suggest the upper unit is a proximal slope apron, downlapping and filling interlobe bathymetric lows of the underlying unit. Sharp-based, blocky/digitate log signatures, discontinuous chaotic reflectors, and coarse-grained sediment characterize this unit.

The lower Andrew represents a structurally focused, sand-rich lobe complex, without associated incised canyons. The Andrew system evolved as the delta platform expanded onto the proximal fan, resulting in a linear sediment source spilling over the slope as a fringing slope apron.

AAPG Search and Discovery Article #90990©1993 AAPG International Conference and Exhibition, The Hague, Netherlands, October 17-20, 1993.