Rapporti fra geomorfologia e neotettonica. Messa a punto concettuale

Relations between Geomorhology and Neotectonics. Conceptual restatement

Abstract

The term morphoneotectonics comprises the relations between landforms and neotectonics. Since tectonic movements modify the surface, modification resulting from recent tectonic movements may be mapped and the possibility of renewed activity can be assessed. Surface modifications caused by Neotectonics may be of various kinds: a) direct geological-type consequences (e.g. uplift, subsidence, faulting, folding); b) indirect geological-type consequences (e.g. variations of sedimentation rate or of detrital accumulation); c) direct geomorphological-type consequences (e.g. mass movements, fault scarps, subsidence); d) indirect geomorphological-type consequences (e.g. adaptations of the land to the modified structural conditions, adaptations that take place following the tectonic phenomenon with varying response times, such as particular forms of ridges or slopes (rectilinear ridges, convex-concave slopes, etc.), asymmetrical valleys, river bends, particular hydrographic patterns, stream piracy, etc.). Very often, the geological modifications (types a and b,) are not visible on the surface, and it is therefore necessary to discover the geomorphological consequences of both direct (c) and indirect (d) types in order to evaluate recent tectonic movements. The neotectonic interpretation of geomorphological consequences is sometimes difficult because they may appear very different in different morphoclimatic zones. Moreover, similar landforms may also be developed by differential erosion, and they may often reflect the concept of equifinality, that is, that similar landforms may be the result of different genetic processes.