Structural Landforms in Basement Terrains

Abstract

Fault scarps are not specific to crystalline lithologies and will therefore be ignored in this chapter, which deals more specifically with mesoscale, or fifth-order ‘sculptural’ landforms as ranked and defined by Cailleux and Tricart (1956). Such landforms reflect the response to differential erosion of lithologies exhibiting contrasting hardnesses and of basement terrains exhibiting heterogeneous structural fabrics. Landform sizes vary lengthwise from a few kilometres to a few dozen kilometres and fall in either of two categories:

• residual bedrock landforms, which are frequently understood to derive from palaeosurfaces of planation as a consequence of a greater resistance to denudation;

• topographic basins, which are not fault-defined and have been hollowed out by etching processes.