Modifications Flashcards
What are glacio-fluvial deposits?
Glacio-fluvial deposits are sedimentary deposits formed by the action of meltwater from glaciers.
Why are glacio-fluvial deposits difficult to identify in the field?
Glacio-fluvial deposits are difficult to identify in the field because repeated advance and retreat of glaciers modify and alter the appearance of landforms, and these deposits are also subject to weathering, erosion, and colonization by vegetation in post-glacial times.
What happens to glacio-fluvial deposits as temperatures continue to rise?
As temperatures continue to rise, the melting and retreat of glaciers result in the production of more meltwater. This leads to a greater expanse and accumulation of outwash material in the pro-glacial zone.
Which landforms will be exposed in greater number and length during the continued retreat of glaciers?
During the continued retreat of glaciers, kames and eskers will be exposed in greater numbers and of greater length.
How fast is Solheimajökull presently retreating?
Solheimajökull is presently retreating at a rate of about 100 meters per year.
What is likely to form at the snout of Solheimajökull in a couple of decades given the present rate of retreat?
Given the present rate of retreat continuing, a pro-glacial lake will probably form at the snout of Solheimajökull within a couple of decades.
What happens to vegetation as temperatures increase?
As temperatures increase, the growing season for vegetation also increases.
How does exposed outwash material become colonized over time?
Exposed outwash material becomes colonized over time, first by mosses and lichens, and then by grasses, flowering plants, and shrubs.
How have periglacial environments traditionally been referred to?
Periglacial environments have traditionally been referred to as being at or near ice sheets.
What are the more accurate characteristics that define periglacial environments?
Periglacial environments are more accurately defined as areas with permafrost (perennially frozen ground overlain by an active layer), seasonal temperature variations (above zero in ‘summer’, albeit for a short period), and freeze-thaw cycles dominating geomorphic processes (frost heave, freeze-thaw).
Where can periglacial environments be found?
Periglacial environments can be found in high latitude areas such as Alaska and northern Canada, continental interiors like Siberia, and in high mountains at lower latitudes including the Plateau of Tibet, Andes, and Alps.
What percentage of the Earth’s land surface do periglacial environments make up?
Periglacial environments make up 25 percent of the Earth’s land surface.
What is the estimated percentage of the Earth’s land surface that has experienced periglacial conditions in the past?
It is estimated that another 25 percent of the Earth’s land surface has experienced periglacial conditions in the past.
What were the conditions like in southern England during the most recent glacial period?
During the most recent glacial period, southern England was ice-free but experienced severe winters.
