Mike J. Young1, Rob L. Gawthorpe1
(1) University of Manchester, Manchester, United Kingdom
ABSTRACT: Structural Controls on Syn-Rift Sedimentation: Insights From Outcrop and Sub-Surface Studies
The growth of normal fault arrays by the interaction and linkage of individual segments is a fundamental process that occurs during rift basin evolution, where it is known to exert significant controls on the development of coeval syn-rift successions. This study integrates structural and stratigraphic sub-surface (Northern North Sea) and outcrop (Suez Rift) data sets to investigate the progressive structural controls on the evolution of syn-rift depositional systems. The evolution of the Murchison Fault (North Sea) can be described by three distinct stages: (i) isolated fault segments (<4 km long) with distinct hangingwall depocenters, (ii) progressive linkage forming two main fault segments (>9 km long) separated by a relay ramp, and (iii) hard linkage of the fault zone by breaching of the relay ramp. The Thal Fault (Suez Rift) has also evolved through the linkage of individual fault segments, with significant along-strike variations in fault throw, and the thickest syn-rift being preserved in distinct hangingwall synclines. The syn-rift stratigraphy in both settings is significantly influenced by the evolution of the major fault structures. These studies reveal that the growth and linkage of normal faults control the temporal and spatial development of accommodation space and sediment supply, thereby determining the nature and variability of the facies and resultant stratal geometries. The results from this study have implications for sequence stratigraphic models and hydrocarbon exploration of subtle, syn-rift hangingwall plays within extensional basins.
AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado