bild

Folded gneiss. Intensively folded gneiss bedrock. Gneiss is a common metamorphic rock formed from sedimentary rocks that are squashed by the high temperatures and pressures deep within the Earth's crust. This process folds the layers of rock producing the banding seen here. Photographed near Geiranger, Norway. (KEYSTONE/SCIENCE PHOTO LIBRARY/DR JUERG ALEAN/SCIENCE PHOTO LIBRARY)