types of glacial landforms Flashcards
what is a pyramidal peak?
three-sided pointed mountain peak
when are pyramidal peaks formed?
when 3 or more back-to-back glaciers carve away at the top of the mountain- creates a sharply pointed mountain summit
what is an example of a pyramidal peak?
Snowdon- Wales
what type of ridges does an arete have?
knife-edge, steep-sided ridges
when are aretes formed?
when 2 corries develop side by side
what gives the arete its jagged profile?
as each corrie erode either side of the ridge, the edges become steeper and the ridge becomes narrower
what is an example of an arete?
Striding Edge in the Lake District
where are corries formed?
in hollows where snow can accumulate- on North facing slopes
what is a corrie?
a bowl-shaped hollow- with a steep back wall and ridges- forming an armchair shape around a hollow, containing a small round lake called a tarn
explain how a corrie forms and changes over time (4 marks)?
dip in the north facing slope fills with water
overtime, scree from freeze-thaw weathering provides abrasive material for the base of the small glacier to erode a deeper hollow via abrasion
the back wall is made steeper because of plucking from the ice at the back of the glacier
the corrie has become deeper with a steeper back wall and a lip at the front of deposited material
what is a tarn lake also known as?
a corrie loch
what is a tarn lake?
a mountain pool or lake in a corrie after the glacier has melted
how is the meltwater held in place in a tarn lake?
because of the corrie lip at the bottom end, the meltwater is held in place and a circular body of water is formed
what are truncated spurs past?
past interlocking spur edges of past river action that have been cut- off forming cliff-like edges on the valley side
where are truncated spurs found?
found between hanging valleys and an inverted v shape
when are truncated spurs formed?
when past ridges/spurs are cut off by the lower valley glacier as it moves past
what is the formation of a truncated spur?
as the glacier moves down the valley it plucks the rock from beneath and those rocks then rub against the bed of the valley,eroding it further- this deepens and widens the valley
at the front end of the glacier it acts as a bulldozer shifting and removing soil, plucking rock from interlocking spurs and truncating them
when is an interlocking spur created?
created as a river erodes the upper valley as it cuts down into the rock and meanders in and out of the surrounding rock
when is this rock removed from interlocking spurs?
during glaciation- removed by descending ice sheets
what is a hanging valley?
a small tributary glacier found hanging above the main valley floor
what happens to hanging valleys when melting occurs?
there are waterfalls onto the valley floor
what is an example of a hanging valley?
Cwm Dyli in Snowdonia
what is an example of a tarn?
Red Tarn in Lake District
what is a ribbon lake?
a long, thin lake
