Journal of Petroleum Geology, Vol.1, No.1, pp. 43-63, 1978

©Copyright 2000 Scientific Press, Ltd.

FRACTURE ANALYSIS IN THE DETERMINATION OF SUB-UNCONFORMITY STRUCTURE: A PHOTOGEOLOGICAL STUDY

J. W. Norman, Ph.D.* and T. C. Partridge, Ph.D.**

*Department of Geology, Imperial College of Science and Technology, London.

**Partridge, De Villiers and Associates, Johannesburg, South Africa. (Formerly chief Engineering Geologist, R. F. Loxton. Hunting and Associates, Johannesburg).

Abstract

This is a record of an attempt to understand the geological structure of an area of several thousand square kilometres where the main interest lies in formations concealed under some 750 to 2500m of unconformable terrestrial sediments. Various fracture trace techniques have been used in an attempt to understand the stress system in the underlying rocks, and to distinguish between movements caused by horizontal and vertical forces. The study resulted in the interpretation of possible anticlines, domes, and drape folds in the underlying rocks, whereas the surface rocks were found to be mainly deformed by differential compaction during diagenesis.