2A.2 Present and past Pleistocene distributions of Ice cover Flashcards

1
Q

Definition and importance of Cryosphere -

A

Ice cover is collectively known as the cryosphere and be classes into a number of different ice forms. Covers 13% of the planets surface.

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2
Q

Ice regions can be found in high latitudes for example -

A

Arctic and Antarctic Circles of more than 65 degrees north and south of the equator of polar cells. Due to very little and insufficient sunlight throughout the year.

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3
Q

Ice regions can also be found in high altitude for example at -

A

Mountain ranges which can be any latitude (for example the Alps) Ice is often constrained within the topography

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4
Q

Thermal characteristics of Polar glaciers -

A

Cold based glaciers have a very cold surface temperature of -20 to -30 degrees and their base is frozen to the bedrock beneath. Little glacial movement only one that can happen is internal deformation.

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5
Q

Thermal characteristics of temperate glaciers -

A

Warm based glaciers are not frozen to the bedrock surface they rest on, at their there is a layer of water, allowing the base of the glacier to slide and move, through basal sliding.

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6
Q

Classification of ice masses -

A

Constrained - no dome shape, so the movement is influenced by the surroundings - Cirque glaciers

Unconstrained - The flow and shape is not influenced by its surroundings, ice sheets, shelves and caps.

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7
Q

Ice sheets -

A

Ice sheets are unconstrained types of glaciers, they are largely domed shaped and cover underlying topography found more commonly in Antarctica and Greenland. Cover more than 50,000 km cubed

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8
Q

Ice caps -

A

Unconstrained glacier types which covers less than 50,000 km cubed and can flow in multiple directions, these are versions of smaller ice sheets E.G Svalbard

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9
Q

Ice fields -

A

Ice fields are ice sheets covering a mountain plateau with some mountain peaks flowing through

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10
Q

Ice fields -

A

Ice that covers a mountain plateau, doesn’t extend to high-altitude areas for example the Himalayas, unconstrained

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11
Q

Valley glaciers -

A

Unconstrained, ice is surrounded by high mountains and fills the valleys, ribbon shaped and vary in length from a few kilometres to over 100 km , examples can include in the Himalayas

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12
Q

Cirque glaciers -

A

Unconstrained, smaller glacier occupying a hollow on the mountain range, carves out a corrie or cirque, smaller versions are known as a niche glacier.

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13
Q

Cold based glaciers -

A

Referred to as polar glaciers, which occur in high latitude particular in Greenland and Antarctica ice temperature is usually below 0 degrees, extreme surface temperature can be as low as -20 degrees - - degrees. Relatively little surface melt in the short and cool polar summer, glacier is permanently frozen to it’s bed.

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14
Q

Warm based glaciers -

A

Referred to as temperate glaciers which occur in high altitude regions outside a polar region, the temperatures fluctuate below and above pressure melting point. Due to increased pressure of overlying ice, water exists as a liquid at temperatures below 0 degrees, glacier has lot’s of debris in it’s basal layers and significant in subglacial depositional features.

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