The glacial and periglacial heritage of the Courel Mountains UNESCO Global Geopark (Galicia)

Abstract

Courel mountains are located in Galicia, Northwest Iberian Peninsula (between 42.715° N; 42.32° N and 7.023° W; 7.42° W). A group of embedded valleys and cramped watersheds that expand in North-South direction characterizes their relief. The sector is lithological dominated by slabs, quartzites and limestones with small outcrops of diabase. The tectonic dynamics set up after Cenozoic intensively fractured the materials that created relevant strike slip faults with a general direction NNE-SSW. Also, in this sector appear other fracture systems with directions NW-SE and W-E, that fragmented the terrain and delimited a great cluster of blocks with sigmoidal shapes that defining large sectors. Fluvial network is conditioned by this discontinuities system that draw the valleys direction, but also, singularly, by their lithology.

During the recent Pleistocene, possibly between 40,000 and 11,000 years ago, the dominant climate was cold with phases with different temperature and humidity. This caused the remodeling large sectors in relation to glacial and periglacial processes. The first ones led their evidences in the erosive landforms, as glacial cirques and glacier thresholds, or accumulative forms, as the moraine crests. The second processes shaped in stratified slope deposits in the slopes or in boulders slopes.

Through fieldwork, geomorphological mapping and sedimentological analysis of deposits, nine glacial complexes have been recognized on the eastern and western slopes of the Courel Mountains, as well as many deposits of periglacial origin.