glacial processes

Question 1

abrasion

Answer 1

as the ice moves over the valley floor, the jagged rocks and stones embedded at the base and sides of the glacier scrape along the valley sides and base

this acts like sandpaper, smoothing the rock below

where the rocks embedded in the glacier scratch along the surface, striations may be left on the rock surface

striations are scratch marks on the rock surface and they can help determine the direction of ice movement

Question 2

plucking

Answer 2

as a glacier slowly travels downhill, loose rocks and stones from the valley floor and sides freeze onto the glacier

as the glacier moves down slope by gravity, these rocks and stones are then torn away, producing a rough, jagged surface

by teasing away huge rocks, the valley sides are left very steep and the base very flat

these rocks then become incorporated into the base and sides of the glacier and will assist with abrasion

Question 3

freeze thaw weathering

Answer 3

a process of erosion that happens in cold areas where ice forms

a crack in a rock can fill with water which then freezes as the temperature drops

as the ice expands, it pushes the crack apart, making it larger

when the temperature rises again, the ice melts, and the water fills the newer parts of the crack

the water freezes again as the temperature falls, and the expansion of the ice causes farther expansion to the crack

process continues until the rock breaks