Fossil ice wedges and ground wedges in sediments below till at Voss, western Norway

In a 3 to 4 m high section, the following four distinct sediment units exist: At the base a well-sorted sand of uncertain origin; above this a bed of till (believed to be lodgement till); above this bedded sand, silt and clay, presumably deposited in an ice-dammed lake; and on top, a younger lodgement till. All the sediments below the upper till are cut through by two different types of wedge-like structures. The wedges of the first type are filled with unsorted sediments and are interpreted as fossil ice wedges. The second type consists of vertically laminated clay and silt, presumably a kind of ground wedge. The sediments and the wedge structures are believed to be of either Allerod/ Younger Dryas age, or from older Weichselian interstadials.