What is a drumlin and how is it formed?
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What is a drumlin and how is it formed?
Drumlins are oval-shaped hills, largely composed of glacial drift, formed beneath a glacier or ice sheet and aligned in the direction of ice flow.
What is drumlin in geology?
Drumlins are hills of sediment (generally a quarter of a mile or more in length) that have been streamlined by glacier flow. Thus, they are often elongated. They often occur together in fields, some with as many as several thousand individuals.
What is special about a drumlin?
Generally, they are elongated, oval-shaped hills, with a long axis parallel to the orientation of ice flow and with an up-ice (stoss) face that is generally steeper than the down-ice (lee) face. Drumlins are typically 250 to 1,000 meters long and between 120 and 300 meters wide.
How is a Roche Moutonnee different from an drumlin?
The contrasting appearance of the erosional stoss and lee aspects is very defined on roches moutonnées; all the sides and edges have been smoothed and eroded in the direction travelled by the glacier that once passed over it. In a drumlin, the steep side is facing the approaching glacier, rather than trailing it.
What is a erratic in geography?
Glacial erratics are stones and rocks that were transported by a glacier, and then left behind after the glacier melted. Erratics can be carried for hundreds of kilometers, and can range in size from pebbles to large boulders. Scientists sometimes use erratics to help determine ancient glacier movement.
What is the difference between a drumlin and a moraine?
Drumlin: An elongated, teardrop-shaped hill. These streamlined hills were sculpted in the direction of the glacial ice movement. End Moraine: A type of moraine formed at the outer edge of a glacier or glacial lobe where it paused or stopped.
What are drumlins used for?
Glacial geologists frequently use these swarms of drumlins in palaeo-ice sheet reconstruction, because they can be directly related to the direction of former ice flow. They can therefore be used to reconstruct the dynamic behaviour of former ice sheets (Livingstone et al., 2010; Livingstone et al., 2012).
Where is a Drumlin?
Drumlins are commonly found in clusters numbering in the thousands. Often arranged in belts, they disrupt drainage so that small lakes and swamps may form between them. Large drumlin fields are located in central Wisconsin and in central New York; in northwestern Canada; in southwestern Nova Scotia; and in Ireland.
What does Ice Age mean in history?
ice age, also called glacial age, any geologic period during which thick ice sheets cover vast areas of land. A number of major ice ages have occurred throughout Earth history. The earliest known took place during Precambrian time dating back more than 570 million years.
What is the difference between sheet glaciers and mountain glaciers?
Alpine glaciers are also called valley glaciers or mountain glaciers. Ice sheets, unlike alpine glaciers, are not limited to mountainous areas. They form broad domes and spread out from their centers in all directions.