ABSTRACT

This paper examines a class of numerous widespread vertical faults generally characterized by comparatively long strike lengths. They appear to penetrate to the asthenosphere, and show vertical movement that acted to maintain or restore the isostatic equilibrium of the lithosphere during one or more widely separated geological time periods.

These faults have effectively controlled the position of a large number of stratigraphic (clastic and carbonate), structural and diagenetic hydrocarbon traps. Examples are shown. Some methods of exploring for these faults are also considered.

A theory is advanced to explain the widely separated times of fault movement. Faulting occurs only when the normal major horizontal compressional force due to the resisted forward motion of the lithospheric plate is weak or absent. Absence of this force lessens the friction along these vertical fault planes and permits the restoration of isostatic equilibrium.