Fracture patterns on the Canadian Shield: a lineament study with Landsat and orbital radar imagery

Abstract

Sixty Landsat scenes of the Canadian Shield have been used to map lineaments in a test of the regmatic shear theory, and to evaluate orbital remote sensing methods for the study of high-latitude low-relief shields. It has been found that most lineaments represent a natural class of brittle fractures (joint sets or normal faults) formed by crustal extension. Many lineaments are associated with Precambrian diabase dyke swarms, suggesting that both they and parallel unfilled fractures resulted from uplift and bending of the crust by mantle plumes. There is no unified lineament pattern for the entire shield or even for crustal provinces. However, photogeologic interpretation may be biased against compressional features eroded, and many thrusts, reverse faults, and wrench faults have probably been missed. -from Authors