Glacitectonic rafting of chalk bedrock : Overstrand

A glacitectonic raft is defined as “…a fragment of substratum with preserved original lithological
character, detached from its primary bed and transported due to glacial activity, occurring within or
immediately adjacent to corresponding glaciogenic deposits…” (Ruszczynska‐Szenajch, 1987; Evans,
2007). The distinguishing factor of a raft compared to an erratic is that the latter refers to a single
consolidated clast transported in a matrix, whereas a raft is generally observed as a fault‐bound
wedge of relatively unlithified sediment. In contrast to sediment slabs involved in moraine ridge
formation (Krüger, 1996), rafts are more capable of maintaining their lithological structure and can
be transported comparatively large distances rather than being limited to local thrusting under
direct stress from advancing ice.