TEMPO E MAGNITUDE NOS PROCESSOS GEOMORFOLÓGICOS.

Despite de absence of the usage of a time scale in several geomorphology works, it represents a pivotal variable on the understanding of morphodynamic processes. With the addition of new methodologies to landform analysis by means of geochronological, paleoclimatological and neotectonic empirically constructed studies, the concept of time acquired a more complex perspective, aimed at the elucidation of geomorphological problems at distinct spatial scales. Regarding the understanding of formative events cycles, the emergence of recurring periodic cycles must be addressed: tectonic cycles, Mylankovitich orbital cycles, Dansgaard_Oeschger cycles, ENSO cycles, annual season variability. It is important to consider that the method inherent error must be taken into account, for instance, a 10% error in a time scale of 103 years is equivalent to 102 years of the safety interval, thus generating substantial hindrances to the comparison of geochronological data obtained within a 102 years resolution. One of the main implications regarding the way time is addressed in geomorphology is reflected on the equilibrium conceptions. In the case of semi-arid environments the very notion of equilibrium transcends the temporal observation scales of geomorphology. [ABSTRACT FROM AUTHOR]