corrie, arete, pyramidal peak Flashcards
where does snow collect on the mountain, and what does this allow for? BG
snow collects in a north-facing hollow on the side of a mountain. The northerly aspect means greater protection from the sun in the summertime, the snow never completely melts due to snowfall in winter exceeding snowmelt in summer.
the snow compresses. what causes this? and what stages does the snow do so in? BG
the snow begins to compress due to its heavy weight, first into neve, then firn and finally ice.
The glacier moves downhill, doing what? BG
rotating slightly due to gravity
Explain FULLY what happens in the formation of a corrie BEFORE GLACIATION
snow collects in a north-facing hollow on the side of a mountain. The northerly aspect means greater protection from the sun in summer, the snow will never completely melt, it accumulates due to snowfall in winter exceeding snowmelt in winter. The snow begins to compress due to its heavy weight, first into neve, then firn, then ice. This ice then moves downhill, rotating slightly due to gravity
As the glacier moves downhill, it is plucking rocks from the backwall. Explain this process, and what it does to the hollow DG
This is when the ice has frozen around rocks, and when the glacier moves, it pulls these rocks out and takes them with it. This steepens the backwall
Abrasion also occurs. Explain this process and what it does to the hollow DG
This is when rocks embedded in the ice grind away at the rocks below, eroding them and acting like sandpaper. This deepens the sides and bottom of the corrie.
What forms in the glacier near the headwall? DG
Bergshrund Crevasses
What do Bergshrund Crevasses Allow? DG
Falling stones from frost shattering to fall into the glacier, where they can assist in further abrasion
Freezethaw weathering occurs. Where? And Explain this process DG
Freezethaw weathering erodes the back of the hollow. This is when meltwater enters cracks in the rock, freezes, expanding by 9%, which forces the cracks to widen. This is repeated, and eventually breaks apart the rock
As the glacier moves downhill, what kind of movement do we see, and what does it do? DG
As the Glacier moves downhill, we get rotational movement which deepens the corrie.
Explain FULLY what happens what happens in the formation of a corrie DURING GLACIATION
As the ice moves downhill it is plucking rocks from the back wall, this is when ice freezes around the rocks, and when the ice moves it pulls out these rocks and takes them with it, this steepens the backwall of the corrie.
Abrasion also occurs, this is when rocks embedded in the ice grind away at the rock below, eroding it by acting like sandpaper. This deepens the bottom and sides of the corrie.
Bergshrund crevasses formed in the glacier near the headwall allow falling stones from frost shattering to fall into the glacier where they can assist in further abrasion.
Freezethaw weathering erodes the back of the hollow. This is when meltwater enters cracks in the rocks, freezes, expanding by 9% and so forcing the cracks to widen. This is repeated and eventually breaks up the rock.
As the glacier moves downhill, we get rotational movement which deepens the corrie further.
The glacier retreats and melts, leaving behind what? AD
A small lake called a tarn
The glacier deposits its material as a pile of moraine. What does this present as? AG
A larger corrie lip at the front edge, and forms scree along the backwall
Explain FULLY what happens in the formation of a corrie AFTER GLACIATION
When the glacier retreats and melts, a small lake called a tarn is left behind.
The glacier deposits its material as a pile of moraine, forming a larger corrie lip at the front edge and scree along the backwall.
EXPLAIN FULLY THE FORMATION OF A CORRIE
Before Glaciation
snow collects in a north facing hollow on the side of a mountain. the northerly aspect means greater protection from the sun in summer, so the snow never completely melts. The snow accumulates because snowfall in winter exceeds snowmelt in summer. The snow begins to compress due to its heavy weight, first into neve, then firn. then ice. The ice begins to move downhill rotating slightly due to gravity.
During Glaciation
As the ice moves downhill, it is plucking rocks from the backwall, this is when ice freezes around the rocks, and as the ice moves it pulls them away with it. This steepens the backwall of the corrie.
Abrasion also occurs. This is when rocks embedded in the ice, grind away at the rocks below it- eroding it like sandpaper. This deepens the bottom and the sides of the corrie.
Bergschrund crevasses formed in the glacier near the headwall allow rocks from frost shattering to fall into the glacier and assist in further abrasion.
Freezethaw weathering erodes the back of the hollow. This is when meltwater seeps into cracks in the rock, freezes- expanding by 9% which forces the cracks to widen. This repeats, and eventually breaks up the rock.
As the glacier moves downhill, we get rotational movement, this further deepens the corrie.
After Glaciation
The glacier melts and retreats, leaving behind a small lake called a tarn.
The glacier deposits its material as a pile of moraine, forming a larger corrie lip at the front edge, and scree along the backwall.
