Polyphase glaciotectonic deformation in the Contorted Drift of Norfolk

New observations indicate five main phases of deformation. The three advances of the Cromer (North Sea) ice produced three phases of till-related shear foliations, liheations and intrafolial and other folds (01–03). The first Cromer advance from the NNE also probably caused the initial emplacement of most if not all of the large chalk and sand rafts. West of Cromer these structures have been progressively re-worked into a later shear foliation (04) which is shared by the Marly Drift above and to the west. An expansion of Lowestoft ice from the west is most likely to have been responsible for these structures. Finally, rapid deposition of gravel and sand outwash induced the formation of non-glaciotectonic diapiric domes and basins (05).