Remarks on the derivation of the paleostress system from inferred faults on deep seismic reflection records

Abstract

Geological dip-slip faults have become a common feature of interpreted deep crustal seismic reflection records. The applicability of Anderson's theory of faulting to these cases, as argued by previous workers, would allow the derivation of the paleostress system from the dip angle of the fault. Knowledge of paleostress would obviously be important in constraining tectonic reconstructions. Two well-constrained examples of crustal dip-slip faults inferred from deep seismic reflection data (from the Wind River Mountains, Wyoming and the Riddleville buried Triassic-Jurassic basin, Georgia, U.S.A.) suggest that in certain cases the approach can yield reasonable estimates of the coefficient of static friction and the paleostress system from deep, reflection-defined faults. This study, however, also notes that the sensitivity of the calculation of the coefficient of static friction (and thus stress) to the fault-dip angle, together with ambiguities often involved in measuring angles of deep seismic reflectors, may make such estimates meaningless in cases where true dip angles cannot be precisely determined.