EXCEPTIO PROBAT REGULAM: DO EXCEPTIONAL FORMS TEST GENERAL THEORIES?

摘要

Though Brunsden's Ten Commandments are evidence of profound understanding of the factors that determine the shape of the Earth's surface, they are abstruse in expression and so specific in content as to preclude adjustment in the face of changing evidence and concepts. Two substantive questions arise. First, given the spatial and temporal complexities of the Earth's surface, is it possible to derive general statements or laws about its development? And, indeed, is it desirable to do so? Though a framework is useful for pedagogic purposes, it may take on an unjustified aura of respectability and immutability, and stultify rather than advance research and understanding. Second, if guidelines are sought, what factors which Brunsden overlooked or underplayed deserve mention? Water is so significant in several aspects of the denudational complex that it warrants specific consideration. Interactions between bedrock and shallow groundwaters produce etch forms which are widely developed and which are climatically and lithologically largely azonal. Subsurface weathering and flushing may contribute substantially to surface lowering. The survival of very old paleoforms in some instances carries significant implications for the distribution of water erosion in some (structural) conditions, as well as explaining several otherwise puzzling aspects of landscape development such as increasing relief amplitude, relief inversion, scarp steepening and developments in the piedmont zone.