The stratified slope deposits of Tierra del Fogo (Argentina) as an annalogue for similar pleistocene deposits in Galicia (NW Spain)

• Autor(a) principal: Pérez-Alberti, A.
• Data de Publicação: 2016
• Outros Autores: Cunha, Pedro P.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10316/79896; https://doi.org/10.18002/pol.v0i28
• topic: Stratified slope deposits; Cryonival processes; Fuegian Andes; Argentina; Serra do Courel; Galicia; Spain

This paper focuses on slope dynamics in schist/slate materials in cold humid environments. It characterises the sedimentological features and controls involved in the for-mation of stratified slope deposits in two areas with similar topographical, lithological and cli-matic characteristics. In both areas, the slopes have dips >30º and the dominant rock types are schists and slates. In the case of Tierra del Fuego, the sedimentary deposits studied are modern; those in Galicia are Pleistocene in age. The slope processes operating in Tierra del Fuego, gen-erating modern stratified slope sedimentary deposits, throw light upon the interpretation of sim-ilar ancient sediments studied in Galicia. This comparative study reveals the fundamental role played by snow and freeze-thaw cycles in the creation of stratified slope deposits. Firstly, snow cover has a direct effect on the slope, compacting sediments, keeping ground temperature stable during winter, or moving clasts as they slip down the slope or act as a slide ramp. Indirectly, as the snow melts, it creates surface run-off and mud or gravel slides. Secondly, the activity gen-erated by numerous freeze-thaw cycles results in the vertical mobility of clasts. However, the continuous loading of sediments on the slope hinders the formation of coarse-grained pavement. Thirdly, the rock type and slope steepness play an important role in the creation of stratified slope deposits.