Portas de Ródão

The Portas de Ródão are a geological formation located near Vila Velha de Ródão, resulting from the intersection of the hard quartzite relief of the Serra das Talhadas with the course of the River Tagus. At this location, there is a narrowing of the valley, which runs between two steep walls, which reach about 170 m in height, resembling two "gates", one to the north in the District of Castelo Branco, Beira Baixa, and another to the south in the Municipality of Nisa, District of Portalegre, Alto Alentejo.[1][2][3]The embedding of the Tagus began by upward erosion, about 2.6 million years ago, taking advantage of tectonic accidents associated with the Pônsul fault, and occurred in several stages, reflected in river terraces and platforms embedded by erosion, most visible on the right bank upstream of the Portas.The large lake and the great depths immediately downstream from Portas bear witness to the grandeur of the waterfall that must have existed here before the current equilibrium phase was reached.