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.