Journal of Petroleum Geology, Vol.1, No.3, pp. 75-102, 1979

©Copyright 2000 Scientific Press, Ltd.

SPHERICAL HARMONIC DEFORMATION

A. Challinor*

* British National Oil Corporation, 150 St. Vincent Street, Glasgow, G2 5L3

Abstract

A radically new method of structural analysis is proposed which relates the deformation of all rocks to a three-dimensional model of close-packed spheres and deformation ellipsoids. All rocks exist under variable stress conditions and are deformed, but the principles of three-dimensional deformation are poorly understood by many geologists and geophysicists. An understanding of rock deformation in three dimensions is a very valuable aid in geological interpretation and in the search for hydrocarbons. The method proposed provides the geologist, geophysicist and associated scientific disciplines with a means of understanding complex, three-dimensional deformation and attempts to explain all deformational phenomena from mud cracks to plate tectonics. Deformation is a spherical harmonic waveform which, although complex in detail, is intrinsically no more mathematically complicated than the reciprocal of the square root of three. The analysis is illustrated by examples of "compressive" deformation from the Tertiary fold belt of Spitsbergen and the "tensional" or "gravitational" deformation in the Viking Graben of the Northern North Sea.