Section 4 Geostructures

Abstract

Geostructures are bedrock Geounits that have been deformed or displaced by folding, faulting, or igneous intrusion processes. ‘‘The ability to recognize and map geological structures from remote sensing data is dependent primarily on two main factors: the level of bedrock exposure of the mapped structures and their magnitude of deformation.’’ Z. Berger 1994. 18 Units and 16 Variants are ordered in four Groups: Diastrophic Rock Units: are the result of all movements of the crust produced by tectonic processes (Figs. 35 to 38). Gravity Structures: are the result of gravitational forces of dense rocks causing underlying low density rocks to rise (Figs. 39 to 41). Fault Line Traces: are strong linear features in consolidated rocks or coherent surficial material visible in airphotos or imageries possibly or probably resulting from movement reflecting tensional stress. Figures 42, 43, and 44 are examples of known faults. General Lineaments: may be straight or irregular. They include linear arrangements of natural geomorphic or radiometric features marking fracture traces (Fig. 45) and interpreter-drawn mapping lines that mark the natural boundary lineaments of unconformable rock types (Figs. 46 to 49).