Unscramble the words! Zefere Twah Sibarano Gnkpulic Enimroa Llubzngido Freeze thaw Abrasion Plucking Moraine Bulldozing

Erosional Features CORRIE (Cirque, Cwm) Arête, Pyramidal Peak, Tarn Glacial Trough (U-Shaped Valley) Hanging Valley, Truncated Spurs, Ribbon Lake

What does a pre-glacial landscape look like?

What does a glacial landscape look like?

What does a post-glacial landscape look like?

Corrie – Helvellyn Use the processes mentioned so far to describe the formation of the corrie and tarn lake Freeze-Thaw Plucking Abrasion

Corrie & Tarn Animation

How is a Corrie formed? Snow collects in a natural hollow on the side of a mountain. Over time, further snow collects in the hollow. This extra weight compresses the snow underneath, turning it into ice. The hollow is deepened and widened by the corrie glacier through the processes of abrasion and plucking. This over-deepening leads to an ‘armchair’ shape characteristic of a corrie and causes a ‘rock lip’ to be formed.

Inputs – avalanches, precipitation (snow) Store – ice Outputs – meltwater, evaporation Processes of erosion – abrasion and plucking must be described fully. Definitions are usually worth 2 marks each.

Inputs – avalanches, precipitation (snow) Store – ice Outputs – meltwater, evaporation Processes of erosion – abrasion and plucking must be described fully. Definitions are usually worth 2 marks each.

Explain how is a Corrie formed Inputs – avalanches, precipitation (snow) Store – ice Outputs – meltwater, evaporation Processes of erosion – abrasion and plucking must be described fully. Definitions are usually worth 2 marks each.

A Corrie in pictures! Cwm Idwal Steep back-wall Inputs – avalanches, precipitation (snow) Store – ice Outputs – meltwater, evaporation Processes of erosion – abrasion and plucking must be described fully. Definitions are usually worth 2 marks each. Bowl-shaped corrie Tarn

Aretes are “knife-edged” ridges formed between two corries Inputs – avalanches, precipitation (snow) Store – ice Outputs – meltwater, evaporation Processes of erosion – abrasion and plucking must be described fully. Definitions are usually worth 2 marks each.

Pyramidal peaks are formed when three or more corries cut backwards into the same mountain. Arête Tarn Corrie Inputs – avalanches, precipitation (snow) Store – ice Outputs – meltwater, evaporation Processes of erosion – abrasion and plucking must be described fully. Definitions are usually worth 2 marks each.

Label the Pyramidal Peak Diagram Inputs – avalanches, precipitation (snow) Store – ice Outputs – meltwater, evaporation Processes of erosion – abrasion and plucking must be described fully. Definitions are usually worth 2 marks each.

Arêtes & Pyramidal Peaks When two corries form next to each other, and their adjacent walls are eroded backwards until they meet, a narrow and pointed rock ridge is formed. When three or more corries erode backwards we get a pyramidal peak Examples Arête – Striding Edge (Lake District) Pyramidal Peak - Matterhorn

Corrie Steep back wall caused by freeze-thaw and plucking Arm chair shaped hollow that snow and ice accumulate in, carved by a glacier Rock lip at the edge of the corrie formed by deposits as the glacier rotated out of the basin Tarn formed in the deepest part of the corrie as it was scooped out by erosion (abrasion)

Corrie on Maps

Steep back wall created by freeze-thaw and plucking Corrie An arm chair shaped hollow widened and deepened by a glacier. Arete Sharp knife edged ridge between TWO corries. Formed as two corries are eroded and weathered backwards. Named example Striding Edge on Helvellyn in the Lake District

Striding Edge - Matterhorn

Crib Goch - Snowdonia

Pyramidal Peak: Steep mountain formed as three corries retreat backwards Corrie back-wall steepened by freeze-thaw and abrasion

Arêtes and Pyramidal Peak

Corrie Begins as a patch of permanent snow Snow accumulates, becomes ice Begins to flow due to gravity Below the ice there is a scouring action produced by the rotational movement of the ice as it moves down hill, and abrasion from the rock debris held in the ice The rocks embedded in the ice scrape away at the underlying surface, slowly producing a curved hollow. As the ice moves, plucking occurs on the backwall As ice moves, cracks (bergschrunds) occur, allowing water to enter and freeze-thaw to take place Freeze thaw occurs at the very top part of the glacier

This shouldn’t take you long – 15 minutes! Homework task! Your task is to produce a 1 page document showing photographs of each of the features you have learnt about – and some information to accompany them! This shouldn’t take you long – 15 minutes!