Where are glacial troughs found?
Glacial troughs cover 24% and 40% of shelf area of the Arctic and Antarctic shelf environments, respectively, but they are also found on shelves in Chile, British Columbia, Alaska New Zealand and northern Europe.
What is a glacial trough in geography?
Glacial troughs, or glaciated valleys, are long, U-shaped valleys that were carved out by glaciers that have since receded or disappeared. Troughs tend to have flat valley floors and steep, straight sides.
What causes a glacial trough to form?
The formation of a glacial trough involves two processes abrasion and plucking. Abrasion is when pieces of debris in the glacier wear away at the rocks below, a bit like sandpaper. The sharper rocks in the ice can also cause scratches in the rocks called striations.
What is a flooded glacial valley called?
Glacial valley, also called glacial trough, stream valley that has been glaciated, usually to a typical catenary, or U-shaped, cross section. These glacial troughs may be several thousand feet deep and tens of miles long.
Why are glacial lakes dangerous?
This is a glacial lake outburst flood. Global temperatures are rising, and glaciers are melting worldwide. The melting creates feebly dammed glacial lakes that can violently burst. The resulting floods can devastate downstream communities.
What is a glacial burst?
Glacier bursts are a cascading risk. Cascades of glacier bursts, cloudbursts, heavy rainfall and subsequent landslides are becoming more frequent and complex. The breaking of the Nanda Devi glacier triggered a landslide, avalanche, deluge, and flash floods in the intricately linked tributaries of the Ganga river.
What is the difference between glacial valley and river valley?
The formation of glacial valleys does not depend on the gradient but only the volume of the glacier. Larger glaciers carve larger, wider valleysRiver valleys are formed due to the kinetic energy of rivers falling from a steep height.
How can you tell from your profile that the valley was formed by a glacier?
They have a characteristic U shape in cross-section, with steep, straight sides and a flat or rounded bottom (by contrast, valleys carved by rivers tend to be V-shaped in cross-section). Glaciated valleys are formed when a glacier travels across and down a slope, carving the valley by the action of scouring.
How is U-shaped valley formed?
U-shaped valleys have steep sides and a wide, flat floor. They are usually straight and deep. They are formed in river valleys which, during the ice age, have been filled by a large glacier . These glaciers have deepened, straightened and widened the valley by plucking and abrasion.
Where is a famous U shaped valley?
Yosemite National Park
What is the end of a valley called?
The head of the valley or, less commonly, the valley head, refers to the uppermost part of a valley.
Is U shaped valley erosion or deposition?
Glacial erosion produces U-shaped valleys, and fjords are characteristically so shaped. Because the lower (and more horizontally inclined) part of the U is far underwater, the visible walls of fjords may rise vertically for hundreds of feet from the water’s edge, and close to the shore the water…
Do you mean by U-shaped valley?
A U-shaped valley or glacial trough is formed by the process of glaciation. It has a characteristic U shape, with steep, straight sides and a flat bottom. Glaciated valleys are formed when a glacier travels across and down a slope, carving the valley by the action of scouring.
What do u mean by U-shaped valley?
BSL Geography Glossary – U-shaped Valley – definition Definition: U-shaped valleys form through glacial erosion. Glaciation develops in established v-shaped river valleys where the ice erodes the surrounding rocks to create a “U” shaped valley with a flat bottom and steep sides. Glacier movement is driven by gravity.
What landforms are created by glacial deposition?
Glacier Landforms
- U-Shaped Valleys, Fjords, and Hanging Valleys. Glaciers carve a set of distinctive, steep-walled, flat-bottomed valleys.
- Cirques.
- Nunataks, Arêtes, and Horns.
- Lateral and Medial Moraines.
- Terminal and Recessional Moraines.
- Glacial Till and Glacial Flour.
- Glacial Erratics.
- Glacial Striations.
What landforms are created by river deposition?
Erosion and deposition within a river channel cause landforms to be created:
- Potholes.
- Rapids.
- Waterfalls.
- Meanders.
- Braiding.
- Levees.
- Flood plains.
- Deltas.
Which is the best description of glacial till?
Glacial till is the sediment deposited by a glacier. It blankets glacier forefields, can be mounded to form moraines and other glacier landforms, and is ubiquitous in glacial environments.