Formes i modelats glacials i periglacials al Pirineu Oriental

This is a geomorphological study of the river Segre's upper section, including the mountains of Calmquerdos, Tossa Plana de Lles and Port Negre, situated between the valleys of the rivers Valira and Querol (Eastern Pyrenees). The morphogenetic dynamics of quaternary glaciarism have been noted, clearly distinguishing two glacial episodes: one main impulse corresponding with the moraines farther away from the cirques'heads, and a minimal extension reflected by the rock glaciers fixed in the glacial basins. The past action of the periglacial morphoclimatic system has also been discussed, marking the importance that it had in the remodelation of the glacial forms and the slopes below. The paper closes with the study of the actual geomorphological dynamics operating in the supraforestal levels of the mountains in the upper part of the river Segre's Valley. A special attention has been taken in emphasizing the periglacial action on the spatial distribution of the various modellings that give form to those levels