1. A2 Glacial Deposition

2. Glacial Deposition

3. TODAY

4. LAST GLACIAL MAXIMUM

9.  Further compaction squeezes all the air spaces out.  The firn changes to a blue-green glacial ice.  Once it reaches a thickness of 30 - 40 metres, the ice cannot support its own weight and yields to plastic flow.  It now moves downslope under its own weight.

12. Fluvio-glacial environment WATER - SORTED ICE UNSORTED Terminal

18. Glaciers: ERODETRANSPORTDEPOSIT

36. Processes of Transportation: 1. Supra-glacially- on the glacier surface 2. Englacially - inside the glacier 3. Subglacially - at the base of the glacier

37. Why does Deposition Occur? Ice Melting - due to: 1. Pressure Generated Heat 2. Geothermal Heat 3. Daytime Warming - Insolation 4. Warmer temperatures at lower altitudes 5. Prolonged insolation in Polar summers

38. Processes of DepositionLandforms 1. Melt-Out (TILL)Moraines Till Plains Erratics 2a. Fluvioglacial (CONSOLIDATED)Sandurs Varves Drumlins 2b. Ice ContactEskers Kames

39. Landforms 1. Melt-Out (TILL)Moraines Till Plains Erratics

46. Medial Moraine

48. Lateral Moraine

50. Supraglacial Moraine

53. Recessional Moraine

55. Till - unconsolidated - eg Cromer

56. Erratic - eg Norwegian erratics found in East Anglia

57. Landforms 2 Fluvioglacial (CONSOLIDATED) Sandurs Varves

60. Outwash plains / Sandurs. Kames and kettle lakes may be part of this environment.

61. As the ice melts, a hole, or kettle, forms in the debris. This is similar to burying an ice cube in fine sand; when the ice cube melts, a pit develops.

62. Views from Storadimon

65. A small delta

67. VARVES

68. Thick Varves = Warm Temperatures Lots of melting - Ablation Increased Deposition

69. Landforms 1b. Ice ContactEskers Kames Drumlins

71. Sediment deposited

72. Esker - a sinuous ridge of sands and gravels

73. ICE NB supraglacial channels flow to side of glacier (as glacier is slightly higher in the middle. The lateral stream channels are trapped by the valley sides. They carry sediment - hence SORTED deposits - and are different to lateral moraines - which are UNSORTED. Valley Side Valley Side

74. Once the ice has melted away (I.e in an interglacial period) a terrace is left perched up on the valley wall - SORTED deposits

81. Drumlins

82. The situation is further complicated by subsequent re-working of the sediments - for example by climatic cooling and a subsequent ice re-advance.This can make it difficult to establish what a drumlin actually is as the evidence can been bulldozed by ice Example Bangor, North Wales

84. Rock Flour

85. As rock flour enters this lake in Alberta, Canada, it turns the water milky.

86. An iceberg containing glacial debris.

89. What are these landforms of glacial deposition?

90. A2 REVISION GLACIAL DEPOSITION