--> ABSTRACT: Quantification of Slip Rate and Sediment Supply Variations Along Normal Fault Segments: Impact on Sequence Stratigraphy in Marine Rifts, by Robert L. Gawthorpe, Lesley McMurray, Pierre P. Eliet; #91020 (1995).

Datapages, Inc.Print this page

Quantification of Slip Rate and Sediment Supply Variations Along Normal Fault Segments: Impact on Sequence Stratigraphy in Marine Rifts

Robert L. Gawthorpe, Lesley McMurray, Pierre P. Eliet

Studies of the structure and stratigraphy of Quaternary to modern marine rift basins allow tectonic, eustatic and sediment supply controls on depositional sequence to be isolated and quantified. Data from onshore and marine half graben from central Greece indicate marked variations in subsidence around normal fault zones. The variation in subsidence can be related to the segmented nature of normal fault zones, the highest rates of subsidence (up to 5 mm yr-1) occurring adjacent to the fault zone, in the centre of fault segments. Sediment supply also displays systematic variations along fault segments. Sediment supply is low from small, elongate drainage basins developed along the footwall, whereas the main locus of sediment supply is via transfer zones with their large dr inage catchments.

The variation in the rate of subsidence has a major effect on accommodation development around half graben. When compared to the rates of glacio-eustatic sea-level change, the highest rates of subsidence are sufficient to cancel out 4th order eustatic falls, giving rise to a continual relative rise in sea-level, albeit at varying rates. Thus, in the centre of fault segments where subsidence rates are highest, relative sea-level may be rising, whilst at the same time relative sea-level may be falling at other locations around the rift zone.

Computer simulations of stratal geometry and facies stacking patterns using the range of rates of subsidence/uplift and sediment supply observed in central Greece display marked, yet predictable, variations around fault segments.

AAPG Search and Discovery Article #91020©1995 AAPG Annual Convention, Houston, Texas, May 5-8, 1995