Using Fault Kinematics to Evaluate the Relationship Between Cenozoic Fault Activity, Sedimentation Rates and Salt Movement in the Gulf of Mexico - A Comparison Between Southwest Louisiana and Southeast Louisiana

Abstract

Fault initiation and reactivation across south Louisiana during the Cenozoic was driven by either clastic sediment progradation mobilizing underlying salt or by sediment progradation inducing tensional bending stresses during lithospheric flexure. Climate and tectonics within the North American continent during the Cenozoic created differences in the source location, amount of sediments transported, as well as the spatial and temporal distribution of sediments transported into the Gulf of Mexico. This study analyzes 140 fault intercepts along 11 regional cross sections containing well log data in south Louisiana. Cumulative throw, incremental throw, and fault slip rates indicate fault activity punctuated by periods of fault inactivity in southwest and southeast Louisiana. Results show a correlation between the timing of fault reactivation and the location of sediment depositional centers in the Cenozoic. In southwest Louisiana and southeast Louisiana faulting increases significantly in the Oligocene-Early Miocene and Early Miocene respectively during the emergence of new depositional centers in these areas. The pattern of fault activity correlates with the pattern of sediment deposition by showing a similar shift in major activity from southwest to southeast Louisiana through time. The Eocene period marks a time when most faults in southwest and southeast Louisiana were inactive, possibly because the sediment depositional center existed in central Louisiana. These data show that the timing of fault activity correlates with the timing of sediment loading and salt movement as opposed to lithospheric flexure in the Cenozoic.