2 Firstly, what do glaciers have to deposit? As a glacier moves it tears off huge amounts of rocks and othermaterial from the valley surfaces. This material becomesembedded within the glacier and is sorted into different layersdepending on the size of the material.The material carried by the glacier is called moraine.There are 4 different types of moraine;Lateral MoraineMedial MoraineGround MoraineEnglacial Moraine
3 Lateral Moraine:This is the material carried at the top of a glacier or ice sheet at its sides.The material may have been derived from plucking of the valley sides orfrom freeze thaw action on the valley sides.When the ice melts, lateral moraine forms a ridge along the valley.
6 Medial MoraineThis is material transported on top of the ice sheet in the middle.It is formed when 2 glaciers have joined together and their lateral morainemerged.If a glacier has many large tributaries joining it, many lines of medialmoraine form.
8 Ground Moraine This is material carried along the base of the ice The material has been plucked from underlying rock.Most of the material is then abraded to become tiny particles called rock dustWhen the glacier begins to melt it deposits the moraine.
9 Englacial Moraine This is material carried inside the moving glacier The material may be derived from surface moraine which has fallen intoor been washed into crevasses
11 Features of Glacial Deposition Teriminal MorainesRecessional MorainesBoulder Clay PlainDrumlinsErraticsMoraine-Dammed LakesKettle Holes
12 Terminal Moraines:These are formed where ice melts and deposits all the moraine it was transporting at the front of the glacier (snout).The ice sheet/glacier is still moving so material is constantly being added to the terminal moraineThe longer the ice continues to melt at the same place, the higher the terminal moraineIts material will include lateral, medial and englacial moraines, ground moraine and any loose rocks and soil bulldozed in front of itTherefore, terminal moraines are completely unsortedThey may extend for many kilometersThey mark the furthest point reached by the ice sheet or glacier
14 Drumlins: These are hummocky deposits of boulder clay They are 100 – 800m long and 25 – 100m high and oval shapedThe side of the drumlin facing upvalley is steeper than thedownvalley side.Hummocks may build up because ice pauses in its retreat orbecause there is a slightly larger amount of moraine at that pointThe hummocks then become streamlined by the moving glacierflowing over itThey are usually found in groups or swarms
18 Kettle HolesThese were formed by isolated blocks of ice melting more slowly than the rest of the ice-sheetThe melted ice leaves behind boulder clayWhen the block of ice finally melts, the meltwater is trapped by the boulder clay surrounding itThis leaves small, round kettle holes
20 Annotated diagrams may be used. Task 1:Using the information that you have just heard and your notes, answer the following question;Select one feature of glacial depositionand explain the processes involved in theformation of this feature.Annotated diagrams may be used.3 marks