Glaciers – God’s Great PloughsLouis Agassiz

The most erosive force on EarthDavid Attenborough

5th Year Geography

LC Question (2011 HL)Name one landform on the Ordnance Survey map that was formed by

fluvial or glacial or coastal processes and give a six figure grid reference for its location.

Describe and explain with the aid of diagram(s) the processes involved in the formation of this landform.

Marking Scheme Named landform 2 marks Six figure grid reference 2 marks Process named 2 marks Labelled diagram 4 marks graded Explanation 10 x SRPs Give credit for extra labelling in diagram(s) from explanation Feature or process can be starting point Max 2 SRPs if description only of landform.

Glaciationhttp://www.youtube.com/watch?v=AG3luuhc-5Y&feature=relatedhttp://www.youtube.com/watch?v=XOGbOOaPHsw&NR=1

Glaciation

Glacials (col;d)and Interglacials

Glacial MovementBasal flow – weight of ice causes layer closest to ground to

melt – same process used by ice skaters – meltwater acts as a lubricant

Plastic Flow & Rotational SlipPlastic flow – Ice melts around a specific object (like a large

boulder) and the Glacier flows around itRotational slip – ice “rotates” around a central point – like a

child on a swing. Can also be seen in mass movements (e.g. Landslides)

Glacier typesCirque or Corrie Glacier – a build up of ice high up in a hollow

(corrie) in the mountains. Valley Glacier – when the ice build up in the corrie is too great,

the ice spills out and flows downhill as a valley glacierPiedmont Glacier – when two or more Valley Glaciers meetP138http://www.gearthhacks.com/streetview/file.php?fileid=9065

Glacial Processes

ErosionTransportationDeposition

Glacial Erosion Page 140

PluckingAnimation: http://www.homepage.montana.edu/~geol445/hyperglac/eroproc1/animated~plucking.gif

Abrasion: Polishing and Striations (striae)

Glacial TransportMoraines Page 140

Glacial Deposition Page 141

Glacial Landforms

Cirques (Corries) and Tarns P.142Upper and Lower Lough Bray, Co. Wicklow

Devil’s Punchbowl, Co. Kerry

Arêtes & Pyramidal Peaks P.142The Matterhorn, SwitzerlandArête: Between Upper and Lower Lough Bray, Co. Wicklow

Glaciated Valleys (U-shaped valley), Ribbon Lakes P.144

Glendalough, Co. Wicklow.Ribbon Lakes: Glencar, Co. Sligo.

Truncated Spurs

Glencree, Co. Wicklow

Hanging Valleys P.145Glendalough, Co. Wicklow.

Fiords P.145

Killary Harbour, County Mayo/Galway

Geirangerfjord, Norway

Steep Valley Sides

Deep base – Grirangerfjord is more than 600 metres deep – 5 dublin spires could fit into it

5

Summarising….

Features of Glacial Erosion

Cirque/CorrieArête

Pyramidal PeakU-shaped Valley

Ribbon LakeTruncated SpursHanging Valleys

Fiords

Glacial Deposition Page 141

Glacial Deposits and Fluvioglacial Deposits

First let’s do the Glacial Deposits

Boulder Clay Page 146Moraine Page 147Drumlin Page 148Erratic Page 149

Fluvioglacial Deposits

Outwash Plains, The Curragh

EskersEsker Riada, Clonmacnoise, Co. Offaly

The glaciation of Ireland P.151

2 of Europe’s 4 Major Ice Ages Reached Ireland

175,000 – 100,000 Years ago: Munsterian Ice Age

70,000 – 10,000 Years ago: Midlandian Ice Age

Glaciated IrelandThe ice sheets that spread over Ireland had the effect of

“freezing up” the seawater – as a result water levels dropped.This resulted in Ireland, Britain and Europe joined together as

one large landmassWhen the ice sheets melted two things happened

The Sea level roseThe land rose (as it was not being “pushed down” by ice any

more)This resulted in a unique landscape

Glaciated Ireland – sea levels

Midlandian Glaciation from Space