Intraformational clay diapirism and extrusion in Weichselian sediments at Ormehøj (Funen, Denmark)

Abstract

A kamiform hill in the Vissenbjerg dead-ice landscape consists of a basal till, overlain by various glaciolacustrine sediments. Within these sediments diapiric phenomena can be observed; the source is a clay layer, probably occurring just beneath the lodgement till. Pressure gradients between the intraglacial lake and the surrounding dead-ice blocks induced diapiric strain in the clay. Both intrusive behaviour and subaqueous (partly possibly subaerial) extrusive spreading were the result. Deformational structures, caused by this plastic flow, are described, depicted and interpreted.