GG282 Lecture Notes - Lecture 9: Diamicton, Fluvial, Lodgement
Document Summary
At the margin or on the surface of the glacier (supraglacial) As the ice melts out (e. g. englacial materials deposited at bed) Begin in the subglacial environment with materials deposited directly from glacial ice (without modification by water) The material deposited is called till (glacial diamicton) Till may be deposited beneath an actively sliding glacier through a process called lodgement (lodgement tills) Till may be deposited as ice melts out producing melt out tills (ablation tills) Till may be deposited in mass flows, either subglacially or in the supraglacial environment (this produces flow tills) Mixture of fine and coarse sediments (diamict or diamicton) Coarse clasts in till are often angular or subangular, some may show striations. Coarse clasts may have a preferred orientation (called a fabric) Most tills are massive (no bedding or lamination) The properties of tills will reflect several variables, including:
