Glacier erosion Flashcards
Name glacial erosion x4
Glacial plucking
Glacial abrasion
Glacial crushing
Fluvio-glacial erosion
What is glacial plucking
Where well jointed rocks weakens and meltwater is present at base of glacier
The meltwater freezes onto rock
As ice moves caused immense pulling force fracturing and plucking the rock from its original position
What is Glacial abrasion
Material plucked from bedrock is frozen into glacial ice and moved downslope
As it moved downslope the material runs against valley sides, smoother rocks
What is glacial crushing
Direct fracturing of weak bedrock of weight of ice above it.
Bedrock weakened by freeze thaw or repeated glacier advance/retreat (dilation)
What is fluvio-glacial erosion
Basal ice melting beneath temperate glaciers producing large volumes of meltwater allow processes to occur
Abrasion hydraulic action attrition and corrosion
Name landforms produced by glacial erosion x10
Cirque
Arête
Pyramidal peak
Glacial trough
Truncated spur
Hanging valley
Ribbon lake
Roche mountonnee
Knock and lochan
Crag and tail
Description/ formation cirque
Depression in mountainside w/ steep back wall
Rounded hollow in mountain eroded by abrasion and plucking, rotational movement
Description/ formation arête
A narrow knife edge between two cirques
Plucking/abrasion/ freeze thaw on the back wall of cirque mean they erode backwards creating a ridge
Description/ formation pyramidal peak
A pointed mountain peak with three + cirques
Erosional processes causing cirques to erode backwards to each other creating sharp point
Description/ formation glacial trough
A u-shaped valley with steep side and wide floor
A V-shaped eroded to a u due to plucking/abrasion
Description/ formation truncated spur
Steep rocky valley side where spurs of a river valley used to interlock before glaciation
Glaciers less flexible than rivers removing the interlocking spurs by abrasion/plucking
Description/ formation hanging valley
A small tributary V/U- shaped valley above main glacial trough, often has a waterfall w/ river
Erosion occurred quicker vertically meaning tributaries are left high above main valley floor
Description/ formation ribbon lake
A long narrow lake along the floor of a glacial trough
Areas of increased plucking/abrasion by valley glacier deepen part of valley floor creating lake
Description/ formation Roche moutonnee
A mass of bare rock of The Valley floor with a smooth stoss (up valley side) and steep jagged lee (down valley side)
Variation in rock resistance cause ice movement by creep and regelation Stoss the ice scours and smooth rock
Lee refreezing causes plucking
Description/ formation knock and lochan
A lowland area with alternating small rock hills (knock) and hollows/lakes (lochan)
Scouring at base of glacier excavated areas of weak rocks forming hollows filling with meltwater
