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Gerald J Smith1, Robert D Jacobi2
(1) SUNY at Buffalo, Buffalo, NY
(2) SUNY at Buffalo

Abstract: Reactivation of Intracontinental Faults in Foreland Basins and the Effects on Local Sequence Stratigraphy and the Apparent Relative Sea Level Signal

Stratigraphic studies in foreland basins tend to overlook the possibility of reactivation of local faults during times of deposition. However, during orogenic periods the increased regional stress from the collision event and the resulting sediment wedge will cause reactivation of pre-existing faults. The effects of syndepositional faulting during this period of high deposition can generate a localized relative sea level change and thus a localized sequence stratigraphy. This effect is due to the localized change in accommodation space coupled with the potential for creating sediment traps.

Our studies of the Clarendon-Linden Fault System (CLF) in western New York State demonstrates the effect of syndeposition faulting on sequence stratigraphy and the generated relative sea level curve. Deeper sections of the CLF are an intra-Grenvillian fault zone. From well log analysis and seismic studies, the CLF was syndepositionally active during most of the Lower Paleozoic rock record, including the Taconic and Acadian orogenies.

The focus of this report is the clastic sediments in the Upper Devonian Canadaway Group, which define three sequences and generating a relative sea level curve for the area incorporating the CLF. The occurrence of both a black shale basin of the Hume Fm. and the shoreface sequences of the Rushford Fm. (Bradford 3rd Sandstone) would not be predicted from the Devonian eustatic curves; both are considered to be products of the syndepositionally created source and reservoir zones that are spatially confined by the areal extent of the CLF.

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