chapter 3 section 4 glaciers. moving mass of ice and snow form when more snow falls than melts agent...
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GlaciersAdvancing Glacier-When the glacier increases in size and slides forward due to gravity
Retreating Glacier-When the glacier decreases in size because it is melting
Muddy River
Glacier, Alaska 1948
Valley Glacie
r(Alpine
)
•Located in mountainous areas
•Snow and ice build up in a long, narrow v-shaped river valley
Continental Glacier
• Huge mass of ice and snow (larger than valley glacier)
• Usually covers a large portion of land like a continent
• Only tallest peaks of land are exposed
• Today cover 10% of earth's surface (found in Greenland & Antarctica)
Last Ice AgeWhite is land covered in ice.
You are here.Continental glaciers cover large portions of the world at one time
http://cabrillo.edu/~crsmith/glacloop.gif
1. Snow accumulates and piles up faster than it melts
2. Weight of snow is great enough to compress bottom layers into ice
3. Ice on bottom partially melts and becomes putty like
4. Whole mass begins to slide on this putty-like layer
5. When the mass of the glacier is too great, gravity pulls
How do glaciers form and move?
Abrasion & PluckingPlucking-Glacier picking
up rocks as it travelsAbrasion-Glaciers gouge and scratch land below as it moves
How do glaciers erode Earth’s surface?
•As they move, glaciers act as bulldozers pushing loose material out of their path
•These eroded sediments are added to the mass of the glacier (plucking) or piled up along its sides
•Glaciers also grind rock and soil that isn't loose (abrasion)
Terminal Moraine
The ridge of till at the farthest point reached by a glacier (Long Island & Cape Cod-terminal moraine from last ice age)
How do glaciers deposit sediment?•Glaciers begin to melt and lose their energy of motion
•Begin to deposit sediments they carry (till )
•Till at the edges of a glacier (moraine)
•Till at the end of a glacier (terminal moraine)
Kettle Lake Contain water all year long
Kettle lake- kettle that fills with water from melted ice blocks
Glacial LakeGlacial lake- Forms like a kettle lake, but high in the
mountains
Contain water all year long
Horn-mountains with sharp pointed peaks
Arête-sharp edges that run down mountain sides (separating 2 cirques)
Fiord (Fjord)Fiord- a coastal valley cut by glacier that fills in with water when seas rise from glacial melt
Glacier Direction of
flow
Drumlin-mounds of till that a glacier slides over and as the glacier melts back the mound becomes uneven
What am I showing you?
The TILL from plucking & abrasion that will be laid down when the glacier melts