ROLE OF FLUID PRESSURE IN MECHANICS OF OVERTHRUST FAULTING: DISCUSSION

The Hubbert and Rubey mechanism of high fluid pressures operative at the base of low-angle thrust plates is considered inadequate in explaining the development of many thrust faults of diverse nature and geological environments. To support this contention several examples are discussed of thrust faults developed within sedimentary rocks, within metamorphic rocks during regional metamorphism, and within igneous and metamorphic rocks postdating regional metamorphism. Indiscriminate reliance upon the Hubbert-Rubey mechanism may hinder the discovery of additional mechanisms which the writer believes must exist in order to explain the broad spectrum of low-angle thrust fault phenomena.