SMITH-ROUCH, LINDA S., KRIS E. MEISLING, PETER E. HENNINGS, and JOHN M. ARMENTROUT
Using a 2-D forward stratigraphic computer simulation, four experiments were designed to test the relationship between normal fault movement and sediment distribution across a fault plane. Each set of experiments focused on a specific question. 1) Does rate of fault movement effect distribution of sediments across a fault? 2). How is sediment thickness and distribution controlled by fault position? 3) What effect does variable accommodation space (sea level and fault movement) have on sediment distribution and stratal geometries across a fault? 4) What rate ratio (fault movement vs. sediment flux) renders fault movement stratigraphically insignificant? Initial input parameters for fault rates, sediment flux, and sea level were calculated from an offshore Nigeria data set. Simulation iterations tested a range of values for input variables within the context of each question. The authors admit to the limitations of 2-D forward stratigraphic models when attempting to reproduce 3-D fault movement. However, results from experiments identified a quantified link between sediment (lithofacies and thickness) and specific fault position and rate of movement. Also, high resolution simulated delta-front stratal geometries displaced by normal faults provided significant enhancement for seismic interpretation. Another observation revealed that once sediment flux/fault movement ratio reached a specific threshold very little evidence of fault movement was observed in stratal geometries and lithofacies distribution above the fault.