The Solid Earth - Chapter 4: Glacial Erosion Flashcards
As a glacier flows over a fractured bedrock surface, it loosens and lifts blocks of rock, _____ them into the ice, and carries them off
incorporates
The process of ice taking and incorporating rock
Plucking
When does plucking occur?
When meltwater penetrates the cracks and joints along the rock floor and refreezes so that the water expanding can exert leverage
The process of the ice with its load rasping or filing and grinding the surface below as well as the ice
Abrasion
The pulverized rock produced by the glacier grist mill
rock flour
Linear scratches on the bedrock that provide clues to the direction of glacial movement
Glacial striations
Which will produce more glacial striations - fine rocks or larger, coarser rocks?
Larger, coarser
Why does glacial erosion create such jagged, angular topography?
It accentuates what is already there by creating steeper canyon walls and making bold peaks
Ice sheets tend to override the terrain and _____ rather than accentuate irregularities
subdue
As a glacier moves down a valley once occupied by a stream, the ice modifies it by:
glacier widens, deepens, and straightens
The U-shapes result of a V-shaped valley encountering a glacier
Glacial trough
After the glaciers have receded, the valleys of feeder glaciers stand above the main trough and are called
hanging valleys
Rivers flowing through hanging valleys may produce spectacular ____
waterfalls
A hollowed out bowl shaped depression with precipitous walls on three sides and open on the down valley side
Cirque
The cirque represents the focal point of the glaciers ____ (or the area of snow accumulation and ice formation)
focal point
