Home / Estrela UNESCO Global Geopark / Fraga da Pena tor (Geosite), Fornos de Algodres
This site of geological interest shows a large granitic tower (tor) at the top of the western slope of the Muxagata creek. Tors form due to the erosion of sandy materials derived from the deep weathering of granites, which cause the outcropping of fresher and harder core stones. The boulder morphology is controlled by the joint patterns of the bedrock, which give origin to geometric shapes. The initial stage of deep weathering of the granite has occurred a few tens of million years ago, under a warm and wet climate, followed by a stage where erosion prevails when compared to weathering rates.