Alpine Glaciers and Ice Sheets Formation

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Questions and Answers

What is the primary factor that contributes to the formation of ice sheets in polar regions?

Low levels of solar radiation reaching the Earth's polar regions

What is the characteristic shape of the valleys where alpine glaciers are formed?

V-shaped

What is the process by which snow becomes dense ice in the formation of glaciers?

Compaction by its own weight

What is the term for the zone where more ice is gained than lost over a year in a glacier?

Zone of accumulation Signup and view all the answers

What is the term for the floating sheet of ice that is permanently attached to a land mass and is sustained by ice from the mainland and freezing sea water?

Ice shelf Signup and view all the answers

What is the primary mechanism by which glaciers move?

The bottom-most layer of the ice melts due to pressure and gravity, causing it to flow down the slope under its own weight Signup and view all the answers

What is the primary factor that determines the direction of glacial flow, and how does it affect the accumulation of ice?

Temperature is the primary factor, and when the temperature is high, less ice is accumulated and more ice melts, resulting in the glacier moving downhill. Signup and view all the answers

Distinguish between the Zone of Ablation and the Zone of Accumulation, and explain how they impact the size of a glacier.

The Zone of Ablation is where more ice is lost than gained, causing the glacier to retreat, whereas the Zone of Accumulation is where more ice is gained than lost, causing the glacier to advance. The balance between these two zones determines the size of the glacier. Signup and view all the answers

What is glacial ice, and how does it differ from regular ice?

Glacial ice is interlocking crystals of solid H2O that form once the ice and snow's thickness reaches 50m, and it has a definite internal structure while the external may vary. It differs from regular ice in its structure and flow. Signup and view all the answers

What is the role of plucking in the formation of glacial landforms, and how does it relate to freeze-thaw weathering?

Plucking is the process where the glacier picks up rocks and carries them with it when it moves, which is facilitated by freeze-thaw weathering, where water from the bottom of the glacier freezes and expands, making the rock loose. Signup and view all the answers

What is the difference between erosion and weathering, and how do they contribute to the formation of glacial landforms?

Erosion is the process of breaking down rocks into fine particles and carrying them away, whereas weathering is the process of breaking down rocks into fine particles without displacing them. Both contribute to the formation of glacial landforms through the transportation and deposition of rocks and sediments. Signup and view all the answers

What is the significance of moraine in the context of glacial landforms, and how do crevasses form?

Moraine is the residue left behind by a glacier, consisting of rocks and sediment deposited at the snout. Crevasses are cracks in snow or ice that form as the glacier moves, which can be dangerous for climbers. Signup and view all the answers

Study Notes

Glacier Formation and Types

Alpine glaciers form in mountainous regions, often joining together with other glaciers
They are formed in V-shaped valleys, which were previously occupied by streams
Alpine glaciers can range from 1 km to over 100 km in length
Ice sheets, on the other hand, develop in polar regions due to low solar radiation, covering about 10% of the Earth's land area
Ice sheets are thickest near the center and flow outward in all directions

Ice Shelves and Glaciers

Where ice flows over ocean water, ice shelves are formed
Ice shelves are floating sheets of ice permanently attached to a land mass
Shelves become thinner seaward and often break off, forming icebergs
Ice shelves are sustained by ice from the mainland and freezing seawater from below

Glacier Movement and Formation

Glaciers form in upland and polar regions where it frequently snows
Accumulated snow sets and becomes dense ice over time due to its own weight
The bottom layer of ice melts due to pressure and gravity, causing the glacier to flow downwards
This flow is driven by the glacier's own weight and gravity

Zones of Accumulation and Ablation

The zone of accumulation is where snow is compressed into ice over a long period
Where more ice is gained than lost over a year, it is called the zone of accumulation
If accumulation exceeds melting, the glacier advances
The zone of ablation is where more ice is lost than gained, causing the glacier to retreat

Glacial Ice and Flow

Glacial ice is composed of interlocking crystals of solid H2O, forming once the ice and snow's thickness reaches 50 m
Glacial ice has a definite internal structure, but its external structure may vary
Glacial flow can be smooth and continuous, but surges can occur, with rates up to 100 times the normal flow rate

Glacier Parts and Features

The snout is the end of a glacier
Moraine (or glacial till) is the residue left behind after summer melting
Meltwater is the water that flows downslope from melting ice, feeding rivers or lakes
Crevasses are cracks in the snow or ice that can be dangerous for climbers
Striations are long grooves or scratches created as ice flows over bedrock

Formation of Glacial Landforms

Glaciers erode the landscape by picking up materials as they move
Freeze-thaw weathering occurs when meltwater seeps into rocks, causing them to loosen
Plucking occurs when the glacier plucks rocks from the landscape as it moves
Abrasion occurs when rocks and stones in the glacier scrape against each other and the surrounding landscape
Deposition occurs when the glacier deposits rocks and stones at the snout, forming moraines

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Description

Test your knowledge about the formation of alpine glaciers and ice sheets, their characteristics, and their effects on the environment. Learn about the different types of glaciers, their locations, and their role in shaping the Earth's surface. Get ready to explore the icy world!