The Plateau (Periglacial Cake)

The Plateau (Periglacial Cake)

A geological formation with a sloping profile and a rounded shape, situated at the foot of the escarpments on the north-western slope of La Tiñosa.
Geologists call it a ‘periglacial cake’, and its formation dates back to the Quaternary period (two million years ago), a time when periods of cold climate alternated with warmer ones. Through a process known as gelifraction or gelivation, the rocks in the gorges are broken down into small fragments called clasts due to the stresses caused by the freezing of rainwater that fell into their crevices, fractures and pores. In this way, during the glacial periods, significant deposits of loose stones were formed on the northern faces of some of the mountain ranges in the natural park; these were subsequently cemented by the flow of water rich in calcium carbonate during the warmer periods. The cement allows us to calculate the approximate age of these deposits, estimated at around 80,000 years. The rock formed in this way is known as ‘breccia’, and the varying degrees of angularity or roundness of the stones that make it up are due to the greater or lesser distance they have travelled from their place of origin. On the Meseta, the clasts are angular because they have fallen from nearby upper cliffs and have not been subjected to transport by any subsequent river system. The unique geological formation of this site makes it worthy of inclusion on the list of the natural park’s outstanding geosites.