Abstract

Fracture patterns accumulate and direct geologic processes until obliterated by flowage. Some major lineaments, however, have persisted since the Precambrian, affecting sedimentation, tectonics, physiographic expression and localization of economic deposits. Studies reported at this conference and elsewhere have demonstrated the cumulative, persistent, polygenetic, nature of fracture patterns. Cumulative patterns may be initiated by jointing in coals and then subsequently record each episode of differently oriented extension, resulting in the complex fracture patterns of Plateau or Platform regions. These complex fracture patterns can be discerned in adjacent flexure-folded mountain belts by unrolling the bed-related fractures, which had been overprinted by fold-related fractures and post-folding fractures. Most complex fracture patterns are found in old basement which has preserved fractures of Precambrian to Cenozoic age, some of which are propagated to overlying sedimentary cover rocks.