Glaciation
விளையாடிக் கற்றுக்கொள்ளுங்கள்
ஆற்றல் சம்பாதிக்க இந்த கேள்விகளுக்குப் பதிலளியுங்கள், பின்னர் மீன் பிடித்து ஆராயுங்கள். கணக்கு தேவையில்லை.
பாட குறிப்புகள்
Ice Ages and Glaciers
- An ice age is a period when ice covers large parts of the Earth's surface, including areas that are now ice-free.
- During past ice ages, ice extended over much of the UK, shaping the landscape we see today.
- Glaciers are persistent bodies of ice that form where snow accumulates faster than it melts over many years.
- Today, glaciers cover about 10% of Earth's land surface, mostly in polar regions and high mountains.
- Most glacial ice is stored in vast ice sheets in Antarctica and Greenland.
How Glaciers Form and Move
- A glacier forms where the accumulation of snow exceeds ablation (melting and evaporation) over many years.
- Over time, snow is compressed into dense ice that behaves like a slow-moving river of ice.
- Glaciers move under their own weight, flowing downhill due to gravity.
- As they move, glaciers undergo ductile and brittle deformation, creating features like crevasses and seracs.
- The process of glacier growth and flow is called glaciation.
Glacial Erosion
- Glaciers erode the landscape in two main ways: plucking and abrasion.
- Plucking occurs when meltwater freezes onto rocks, and as the glacier moves, it pulls pieces of rock away.
- Abrasion is the scraping of rock fragments embedded in the ice against the bedrock, smoothing and wearing it down.
- Erosion by glaciers creates distinctive landforms such as corries, arêtes, and U-shaped valleys.
Landforms of Glacial Erosion
- A corrie (or cirque) is a bowl-shaped hollow on a mountainside, eroded by a glacier.
- An arête is a sharp, narrow ridge between two corries.
- A pyramidal peak is a pointed mountain top formed where three or more corries erode back-to-back.
- A U-shaped valley is a deep valley with steep sides and a flat floor, carved by a glacier.
- A hanging valley is a smaller valley that meets a U-shaped valley high above its floor, often with a waterfall.
- A ribbon lake is a long, narrow lake found on the floor of a U-shaped valley.
Glacial Deposition
- Glaciers transport material eroded from the landscape and deposit it as moraine.
- Moraine is the name for piles of unsorted rock and sediment deposited directly by a glacier.
- Drumlins are smooth, oval-shaped hills of deposited material, often found in clusters.
- Drumlins are sometimes called 'basket-of-eggs' topography because of their shape.
The Lake District: An Upland Glaciated Landscape
- The Lake District in northwest England is a classic example of an upland area shaped by glaciation.
- It contains many features of glacial erosion, such as corries, arêtes, and U-shaped valleys.
- The long, narrow lakes of the Lake District are examples of ribbon lakes.
- Glacial deposition has also left moraine and drumlins in some valleys.
Glaciers and the Environment
- Glacial ice is the largest reservoir of fresh water on Earth, holding about 69% of the world's freshwater with ice sheets.
- Glaciers store water as ice and release it as meltwater in warmer seasons, providing a vital water source.
- Changes in glacial mass are sensitive indicators of climate change.
- Melting glaciers contribute to sea level rise.
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இலவச முன்னோட்டம் — 59-இல் 8 கேள்விகள். அனைத்தையும் பார்க்க பதிவு செய்யவும்.
1.What is a glacier?
Easy- AA persistent body of natural ice that is constantly moving under its own weight
- BA large block of sea ice that floats on the ocean surface
- CA seasonal layer of snow that never turns to ice
- DA river of meltwater flowing down a mountain
2.Which process is the opposite of accumulation in a glacier's mass balance?
Easy- AAblation
- BPlucking
- CAbrasion
- DCalving
3.Which of these is a landform of glacial erosion?
Medium- ACorrie
- BDrumlin
- CMoraine
- DEsker
4.What is the name for a sharp ridge that separates two corries?
Medium- AArête
- BPyramidal peak
- CHanging valley
- DRibbon lake
5.Which statement best describes how a glacier forms?
Medium- ASnow accumulates over many years and is compressed into ice
- BMeltwater refreezes instantly at the base of a mountain
- CSea ice is pushed onto land by ocean currents
- DRainwater freezes in deep cracks in the rock
6.Which of the following is a depositional landform created by a glacier?
Medium- ADrumlin
- BCorrie
- CArête
- DU-shaped valley
7.What is a pyramidal peak?
Medium- AA sharp mountain peak formed where three or more corries erode backwards
- BA rounded hill of glacial till deposited at the snout of a glacier
- CA ridge of rock left between two glacial valleys
- DA lake formed in a hollow carved by a glacier
8.Which sequence correctly orders the stages of glacial erosion?
Medium- ASnow accumulates, ice forms and moves, plucking and abrasion occur, landforms are created
- BIce melts, snow accumulates, landforms are created, plucking occurs
- CPlucking occurs, snow accumulates, ice forms, abrasion occurs
- DLandforms are created, ice moves, snow accumulates, abrasion occurs
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