Everything Flashcards
Kames
Mounds of sediment found on the floor of a glacial trough, resulting from fluvioglacial deposition in a marginal lake.
Meltwater channels
Often narrow and steep sided valleys formed by torrents of meltwater at the end of a glacial period.
Hanging valleys
Tributary glacial trough perched up on the side of he main glacial trough, often marked by a waterfall.
Frost heave
Small scale upwards displacement of soil particles, resulting from the freezing and expansion if the water just below ground surface.
Glacial trough
Glacially enlarged river valley, large broad flat surface floor with steep sides, U shaped.
Internal deformation
Ice crystals slipping and sliding over each other. They may become damaged or fractured and gradually move downhill due to gravity. Occur in cold and warm glaciers often at the same time as basal sliding.
Basal sliding
The movement of a large block of ice, usually by a series it short jerks. Occurs in warm glaciers where meltwater is present. Obstacles causes added pressure as the ice moves over them, this leads to melting called regelation slip.
Frost shattering
Water seeps into cracks and pores in the rock. Temperature drops to at least 0 degrees and the water freezes expanding in volume. The expansion stresses the rock causing the crack to enlarge. When the temperature rises to above 0 degrees the water melts and the process is repeated causing chunks of rock to beak off.
Describe the distribution of polar and alpine cold environments
Polar, high latitude 60-70 degrees north and South within the arctic and Antarctic circles. Alpine, lower latitude, under he influence of mountains, found along the west coast of the Americas and North of the Indian subcontinent.
Periglacial environments
Found of the ridges of polar and glacial environments, Siberia, Canada, and Greenland. Permanent frozen ground, the warmer summer allows the ground surface layer to thaw enabling some plants to grow.
Extensional flow
When there is a sudden increase in the gradient, the ice will flow faster and may become thinner as it is stretched.
Compressional flow
A reduction in the gradient further down the glaciers means the ice will move slower causing it to pile up and become thicker.
Terminal moraine
Marks the furthest extent of a glacier.
Ground moraine
The rocks grind along the base of the glacier, this moraine can be several metres thick.
Englacial moraine
Rock material buried within the ice having been buried over several year by layers of fresh snow and ice.
Lateral moraine
Consists largely of frost shattered rocks that have fallen onto the glacier from the valley sides.
Accumulation zone
There is a net gain of ice over the year, the inputs exceed the outputs.