| Summary: | The large geomorphological zones of Colombia are defined partly by the climatic levels rising from the equatorial environment and partly by the relief energy; subdivisions of not less importance are determined either by the regional humidity or dryness. Thus the following elements can be distinguished; a glacial level, reaching down to 3000 m. during the recent Quaternary; a periglacial fringe, and a belt of paramos which gas replaced the previous ice-cap; the great forested andine slopes, the valleys and interior dry basins, where the morphogenesis influenced by the steepness of the slopes, corresponds respectively to solifluxion and to water runoff and lastly the hot low-lands which are either wooded or relatively dry and often affected by outside phenomenons. It seems that the principal morphogenetic crisis of the Quaternary is due to drier climates and have affected mostly the mountainous areas and the regions which are actually dry or not very wet. These periods of an undetermined number appear to be contemporary to marine regressions; however, as the glacial area has been wetter during the recent glaciations at least, still a doubt remains, as enough proofs are lacking. Elsewhere, the uplifting of the Andes has seen a decisive period during the upper Pliocene and the tectonic movements have continued up at least to the recent Quaternary. Apart from the direct role which these deformations play in the morphogenesis, they could also account for the inheritance of certain relief forms and pedological alterations which are characteristics of the humid tropical forest climates and which can be noticed actually at high altitude. Les grands domaines géomorphologiques de la Colombie sont définis d'une part par l'étagement climatique du milieu équatorial et, d'autre part, par la vigueur du relief des subdivisions non moins importantes sont déterminées par l'humidité ou la sécheresse régionales. On distingue ainsi : un étage glaciaire qui descendait au Quaternaire récent jusque vers 3000 m une frange ...
|
|---|