Hart and Rose 2001 (1 & 2) Flashcards
A number of methods have been adopted to measure glacier bed deformation, ranging from…
Direct observation and instrumentation, the interpretation of macroscale and microscale sedimentary structures, to the interpretation of glacier bedforms and glacier/bed modelling.
Boulton and Jones (1979), Clarke (1987) and Boulton and Hindmarsh (1987) were amongst the earliest worker to produce new models for glaciers resting on deform- able beds. They showed that…
if the glacier and its bed were coupled, this would lead to an increase in velocity of the glacier and a decrease in thickness and surface slope.
The implications of knowing if the glacier and its bed were coupled, this would lead to an increase in velocity of the glacier and a decrease in thickness and surface slope are…
(i) Climatic forcing and glacier response
- if much of the glacier movement takes place in the underlying sediment, then changes in the deforming layer, such as drainage of the sediment or changes in sediment texture, may have a more dramatic effect on glacier motion than climatic change.
(ii )Fast ice flow
- unexplained discontinuous fast flow in surging valley glaciers, tidewater glaciers and ice streams. Prior to the discovery of the role of deforming beds, this activity was attributed primarily to subglacial hydrology. Currently, explanations are attributed to a combination of deforming bed processes and associated subglacial hydrology
(iii) Glacial controls on climate. Heinrich events in the North Atlantic, which represent a decrease in sea surface temperature and salinity, are thought to be caused by discharges of the Laurentide ice sheet into the North Atlantic from the region of Hudson Bay. These discharges are attributed to binge-purge oscillations of the Laurentide ice sheet (MacAyeal, 1993) with periods of accumulation over an immobile bed, and periods of surge over a mobile bed
The contribution of glacier bedforms to the understanding of subglacial deformation comes primarily from…
the study of flutes in modern glacier forelands, immediately after ice retreat
