Computer Synthesis of Balanced Structural Cross Sections by Forward Modeling

Peter B. Jones, Helmut Linsser

Forward modeling by computer generates unlimited intermediate balanced cross sections, but even the simplest forward modeling casts doubts on many assumptions about fault processes. Geometric and mechanical problems must be resolved before more sophisticated modeling is feasible. Simple models of faulted and folded terranes suggest the following. (1) Fault geometry may lead to erroneous interpretations of fault chronology. (2) Fault duplexes generate many structures that are arcuate in profile or plan, ranging in scale from hanging-wall drag folds to strike-slip continental margins. (3) Thrusts may be generated downward, with ramping controlled by overburden distributed in the hanging wall. (4)Most folds can be generated by a finite number of faults. Calculated depths of etachment of concentric folds are generally misleading. (5) Blind thrusting within an envelope of high fluid pressure reduces mechanical problems inherent in models that restrict high fluid pressures to a basal decollement. Blind normal faults also occur. Blind thrusting may be the predominant mode of compression in layered rocks.

AAPG Search and Discovery Article #91043©1986 AAPG Annual Convention, Atlanta, Georgia, June 15-18, 1986.