Interpretation of Late-Cenozoic Paleo-stress Regimes of Meeman-Shelby State Park, Western Tennessee

Meeman-Shelby State Park of West Tennessee, located 24 km north ofMemphis, TN, within the third Chickasaw Bluff, is a prime location foridentifying and interpreting Late Cenozoic paleo-stress fields of the centralMississippi embayment. Exposures in the streams along the bluffs includeEocene Jackson Formation, Pliocene Upland Complex, Pleistocene LovelandLoess, Roxana Silt, Peoria Loess and Quaternary alluvium. Field work involvedmeasuring the attitudes (strike & dip) of outcrop-scale structures (joints, faults,folds). These data will allow an estimation of paleo-stress regimes duringfracturing and folding and changes in the stress regime between depositions ofeach stratigraphic unit. In an effort to determine the influence tectonic eventshave over geomorphic events, landslide processes are investigated. Myinvestigation shows Quaternary normal faulting sub-parallel to the strike of thesoutheast margin of the New Madrid Seismic Zone, Eocene and Pliocene jointing,Pliocene liquefaction, and Pliocene to Quaternary landslides. Due to a limiteddistribution of datable sediments, age constraints and slip rates are difficult todetermine. However, faulting and liquefaction features reveal evidence ofmultiple seismic events occurring from the Pliocene to Quaternary periods. Datahas also revealed a remarkable change in stress orientations between the Eoceneand Quaternary periods. This research provides much needed insight intoestablishing a time-table of Late Cenozoic seismic events and changes in thestress regime in Shelby County, TN