Glaciation Flashcards
what is a corrie?
its an armchair shaped hollow on a high mountain with steep back and side walls. after glaciation it may fill with ice.
explain plucking
when rocks freeze to a corrie wall and plucks rocks from it
what is a tarn?
small mountain lake left in area when the glacier melts
explain the process of abrasion
rocks from plucking and freeze thaw freeze in a glacier and scrape away the valleys base and sides
what is freeze thaw?
water enters cracks, freeze, expands and thaws widening the crack. this is repeated until the crack fores the rock to break apart
what is an arete?
a sharp mountain edge made from two corries facing back to back
what is a pyrimidal peak?
a sharp mountain peak formed by three or more corries back to back
how do truncated spurs form?
by interlocking spurs created by a river
what is a hanging valley?
are former tribuary glacier valley - smaller valley that meet the main glaciated valley
explain what a ribbon lake and misfit stream is
misfit stream - stream occupying valley, ribbon lake - long ass lake running through U/V shaped valley
Corries
Snow gathers in north facing hollow. The snow builds up and compacts into neve/ ice. Gravity pushes it down so it sticks to wall and plucks rocks from surface. The rocks loosed act like sandpaper and deepen the hollow by attrition.
It’s heaviest at top and has a rotational movement. Front is eroded - lip is formed.
Glacier retreated and often leaves a tarn behind
U shaped valley
Process of a corrie although the glacier uses plucking and abrasion to widen/steepen and smooth the the walls from a V to a U.
The sides got truncated/ interlocking spurs where glaciers eroded interlocking spurs. Small sections have hanging valleys with tributary rivers running into the main ribbon lake. Glacier continues downhill until it stops
