glaciation Flashcards
how is a corrie formed
snow collects in a hollow of a mountainside and over thousands of years it forms a glacier as the glacier grows gravity causes it to move this motion is called rotational slip as the glacier moves plucking occurs on the back wall this along with freeze thaw weathering provides tools for abrasion which deepens the hollow. a rock lip might form at the front of the corrie. when temperatures increase the ice in the corrie melts and a circular lake is formed at the bottom of the hollow
what is abrasion
rocks that have been frozen into the glacier scrap the bed rock like sandpaper leaving striations behind
what is plucking
rocks that have been frozen into the glacier plucks or tears away pieces of rock from the ground
the formation of a ribbon lake
as a glacier flows it travels over hard and soft rock softer rock is less resistant to erosion so a glacier will carve a deeper trough over this type of rock when the glacier has melted water collects in these deeper areas
formation of a drumlin
drumlins are egg shaped hills formed of till they are elongated features that can reach a kilometre or more in length and over 50 m in height
formation of a truncated spurs
trucated spurs are past interlocking spurs edges of past river action that have been cut-off forming cliff like edges on the valley side they are found between hanging valleys
formation of a hanging valley
a hanging valley is a shallow valley carved by a small tributary glacier
when the ice melts the height of the valley floor is left hanging high above the valley floor eroded by the larger trunk glacier
what is freeze thaw weathering
During the day when temperatures are higher, the snow melts and water enters the cracks in the rock. When the temperature drops below 0°C the water in the crack freezes and expands by about 9 per cent. This makes the crack larger.
how does an arete form
it is formed when two neighbouring corries run back to back. As each glacier erodes either side of the ridge, the edge becomes steeper and the ridge becomes narrower.
what is moraine
are mounds of poorly sorted till where rock debris has been dumped by melting ice or pushed by moving ice.
what are erratic’s
are boulders carried by ice, often for many kilometres, and deposited in areas of completely different rock type.
how does glaciers carry sediment
As the glacier melts, the water carries fine material which is eventually deposited. All of the material moved by the glacial melt water is called glacial till. Glacial outwash is the sand and gravel deposited by the running melt water leaving the glacier.
what is lateral moraine
As the glacier melts, the water carries fine material which is eventually deposited. All of the material moved by the glacial melt water is called glacial drift or glacial till. Glacial outwash is the sand and gravel deposited by the running melt water leaving the glacier. The material is sorted.
what is terminal moraine
Terminal moraines or end moraines as they are often referred to are ridges of unsorted material at the snout of the glacier. They mark the furthest point reached by the ice sheet or glacier. Terminal moraines form when the ice melts and deposits all the moraine it was transporting at the front of the glacier.
what is medial moraine
Terminal moraines or end moraines as they are often referred to are ridges of unsorted material at the snout of the glacier. They mark the furthest point reached by the ice sheet or glacier. Terminal moraines form when the ice melts and deposits all the moraine it was transporting at the front of the glacier.
