--> --> Abstract: Tectonic Controls on Turbidite Dispersal Patterns in the Upper Jurassic Brae Complex, South Viking Graben, North Sea Rift, by Sanjeev Gupta, Rodger Connell, John R. Underhill, Phil Allen, and Mark Stephenson; #90914(2000)

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Sanjeev Gupta1, Rodger Connell2, John R. Underhill3, Phil Allen4, Mark Stephenson4
(1) Imperial College, London, United Kingdom
(2) N/A, Aberdeen, United Kingdom
(3) Edinburgh University, Edinburgh, United Kingdom
(4) Marathon Oil UK, Aberdeen, United Kingdom

Abstract: Tectonic controls on turbidite dispersal patterns in the Upper Jurassic Brae Complex, South Viking graben, North Sea Rift

Footwall-derived submarine fan systems are important exploration targets in extensional basins, however, the factors governing temporal and spatial variation in sediment dispersal patterns are not well understood. We examine processes governing turbidite fan distribution and evolution in the Upper Jurassic Brae Complex on the western flank of the South Viking Graben, North Sea Rift. In Block 16/07, the Brae complex comprises a set of three major point-sourced fans and smaller subsidiary fans developed along the rift border fault. The following systems are recognised: (a) a fault-scarp apron, comprising mud-matrix debris flow breccias derived from submarine erosion of fault scarps, (b) point-sourced fan complexes, comprising debris flow conglomerates and turbidite sandstones that form multiple channel and depositional lobe elements, and (c) a finger-like aggradational channel complex. Analysis of a biostratigraphically calibrated well database, 3-D seismic data, integrated with facies interpretation of core data, permits reconstruction of these depositional systems particularly in their proximal setting. Resultant mapping clearly demonstrates the along-strike variability caused by the development and demise of these systems both spatially and temporally. We suggest that the fan and channel tracts were fed from bedrock canyon systems pinned in the footwall at locations inherited from zones of fault linkage during the early synrift, and possibly older major structural elements. This interpretation contrasts with earlier models that invoked paleodrainage localisation along transfer faults. Termination of the fan complexes may be linked to tectonically controlled drainage reorganization in the footwall and/or to subregional flooding of the footwall block.

AAPG Search and Discovery Article #90914©2000 AAPG Annual Convention, New Orleans, Louisiana