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.