Glaciation Flashcards
what is a corrie
an armchair shaped hallow, on a high mountain with steep back and side walls. After glaciation it may fill with ice
how do corries form
snow gathers in south facing hallows. The snow builds up and compacts into ice because of the weight (neve.) As gravity pushes it down it sticks to the walls and plucks rocks from the surface. the rocks loosen and acts like sand paper deepening the hollow (abrasion.) Ice in the corrie has a rotational movement, the front is less eroded and a lip formes. The Glacier retreats often leaving a tarn at the base.
What is a Tarn
small mountain lake left in the base after the glacier melts
what is Neve
compacted snow turned into ice
What is the rock lip
the build up at the front of a corrie
explain the process of plucking
rocks freeze to the corrie wall and plucks rocks from it
Explain abrasion
Rocks from plucking and freeze thaw freeze in the glacier and scrape away at the valleys base and sides - deepening it
what is Freeze Thaw
water enters cracks,freezes, expands and thaws, widening the crack. Repeated until the crack forces the rock to break apart
how do U shaped valleys form
The same process of a corrie although the glacier uses plucking and abrasion to widen, steepen and smooth the V shaped valley into a U one. The steep valley sides have truncated spurs and interlocking spurs where the glacier eroded the interlocking spurs. Smaller sections have hanging valleys with tribuary rivers running into a main channel river. Glacier continues to move downhill until it stops.
What is an arete
sharp mountain edge made sometimes from two corries facing back to back
what is a pyramidal peak
sharp mountain peak formed by three or more corries facing back to back
explain what a truncated spur is
interlocking spurs created by a river
Explain what a hanging valley is
when smaller valleys surrounding the corrie/valley meet the main glaciated valley - they are also former tribuary glaciated valley
explain a ribbon lake
a long river running through the U/V shaped valley
what is a misfit stream
a stream occupying a valley
