Aerial photograph of the Texel Mountains, Oetztal Alps, Italy. The bright marble, dark mica schist and gneiss which form the Texel Mountains today, endured a particularly harsh treatment. Under enormous heat, they were pressed into the Earth?檚 interior twice ??before and during the Alpine orogeny. At last they were 'cooked' 50 kilometres deep in the Earth's crust at a temperature of 650 degrees Celsius. Finally they were pushed upwards over only 20 million years, which is quite fast from the point of view of geology.