Controlled moraines: origins, characteristics and palaeoglaciological implications

摘要: Abstract Controlled moraines are supraglacial debris concentrations that become hummocky moraine upon de-icing and possess clear linearity due to the inheritance of former pattern debris-rich folia in parent ice. Linearity is most striking wherever glacier ice cores still exist but it increasingly deteriorates with progressive melt-out. As a result, has low preservation potential deglaciated terrains tracts previously interpreted as evidence areal stagnation may instead record receding polythermal margins which was concentrated frozen toe zones. Recent applications modern glaciological analogues palaeoglaciological reconstructions have implied that: (a) controlled development can be ascribed specific process (e.g. englacial thrusting or supercooling); (b) good enough imply occurrence snouts ancient supercooled snouts). These assumptions tested using case studies construction wide range entrainment thickening mechanisms seen produce same geomorphic features. Polythermal conditions crucial concentration via processes effective at glacier–permafrost interface. End lie on process–form continuum constrained by basal thermal regime. The morphological expression structures ridges while retain cores, final deposits/landforms tend consist discontinuous transverse intervening hummocks, preserving only weak impression structure. arranged arcuate zones up 2 km containing ice-walled lake plains lying down flow streamlined landforms produced warm-based A variety signature. Spatial temporal variability relationships will lead sequential different types end during recession sheet margin.