1.4 Understand how moving ice acts as an agent of erosion and deposition. (Chap. 2) There are two types of glaciation. Continental Glaciation Alpine Glaciation Distinguish between the terms alpine glaciation and continental glaciation. (P.32) Continental Glaciation • Continental glaciers cover parts of continental land masses; ex Greenland Alpine Glaciation • Alpine glaciers form high in mountain valleys; above the snow-line C D E B A Alpine Glaciation Distinguish between the terms alpine glaciation and continental glaciation. (P.32) Similarities Differences • Both move and cause erosion • Both change the landscape • Both developed in constantly cold < 0 0C • Location • Alpine = mountain • Continental = earth poles • Size • Alpine = smaller • Continental = larger Define the terms outwash plain, terminal moraine, erratics, drumlins & eskers. (P. 33 Q.12) • These features are associated with continental glaciation. • See picture p. 34 Outwash plain Outwash plain • Similar to a river delta • Melt water flowing from the glacier deposits silt • Deposited in layers • Small particles carried further away • Larger particles drop closer to the glacier Outwash Plain Continental Glacier – Outwash Plain Outwash Plain Continental…Outwash plain Continental…Outwash plain Terminal moraine • Heap or ridge of bulldozed gravel that marks the end of the forward motion of a glacier • As glacier retreats it deposits debris/gravel • P. 34 Continental…Terminal Moraine Terminal Moraine Outwash Plain Continental…Terminal Moraine Erratics • Large boulders that were transported long distances and dropped • They now sit in a region and look very much out-of-place. • P. 34 Erratic Erratic Continental…Erratic Terminal Moraine Outwash Plain Erratic Drumlins p. 34 • Egg shaped hill • Formed under glaciers • Sloped or Pointy end points in direction of ice flow Drumlins p. 34 • Formation • Ice melts under glacier • Deposits of gravel made • Glacier moves forward • Deposits are bull-dozed along and catches up in rough areas forming piles or drumlins. Drumlin What direction did the glacier move? Continental…Drumlin Drumlins Terminal Moraine Outwash Plain Erratic Esker p. 34 • Long deposits of eroded glacial material • Formed by sub-glacial streams that deposit material like all rivers. • Highways of the North!! Esker Esker Continental…Esker Drumlins Terminal Moraine Esker Outwash Plain Erratic Examine evidence for the direction of movement of glaciers. (P. 34 question # 13) 1. Sloped end of drumlin 2. Location of terminal moraine • What is direction of glacier movement in this picture? Continental…Outwash Plain Define the terms cirque, arête, hanging valley, lateral moraine, and terminal moraine. (P. 36) • These features are associated with alpine glaciers Alpine glaciers • Alpine glaciers are like very slow moving rivers of ice flowing down high mountain valleys. Cirque (p. 36) • a circular hollow cut into bedrock during glaciation • Side and back walls are steep but front wall opens downward Cirque - How formed? • Alpine glacier freezes onto mountain valley and as is proceeds it plucks rock from the mountain top leaving the cirque shape. C D E Cirque B A Cirque Arête p. 36 • Steep, jagged, narrow, knife edged ridge between two cirques or glacier valleys. Arete C D E Cirque B A Arête Truncated Spur • Blunt-ended ridge of rock jutting from the side of a glacial trough, or valley Arete C Truncated spurs A D E Cirque B Horn or Pyramidal Peak • is a mountaintop (peak) that has been modified by the action of ice during glaciation. Arete C Truncated spurs A Horn D E Cirque B Horn Hanging Valley Most noticeable once glacier has melted! • A high level tributary valley from which the ground falls sharply to the level of the lower, main valley. • The depth of the lower valley is due to more severe glaciation. Hanging Valley Hanging Valley Hanging Valley in Newfoundland • Hanging Valley in Gros Morne National park . • Trout River pond Lateral Moraine • Moraine means 'rock waste'.It is also known as glacial till • Lateral Moraine is the land-form deposited at the side of a glacier • Debris/waste rock drops off the side of the mountain as the glacier moves forming a ridge of debris at the outer-sides of the glacier. Lateral Moraine •Lateral Moraines Kaskawulsh Glacier St. Elias Mtns - Arctic Terminal Moraine • deposits that mark the farthest extent of the glacier • Good indicator of the direction or movement of the glacier as well. Alpine Glaciation • Terminal Moraine Medial Moraine • This is a ridge of rock waste found along the middle of the floor of a u - shaped valley. • It occurs when two glaciers meet, two lateral moraines unite to form a medial moraine. Medial Moraine •Medial Moraine Medial Moraine • Medial Moraine Alpine Glaciation Kaskawulsh Glacier St. Elias Mtns - Arctic Describe how fiords are formed. (P.37) 1. Alpine Glaciers erode troughs & valleys in the mountain 2. Glacier valley reaches the coast. 3. Glacier melts and sea water floods the valley Fiord • A glacially eroded or modified U-shaped valley that extends below sea level and connects to the ocean. Filled with seawater… Gross Morne - Fiord Fiord in Norway • Norway is well known for its abundant fiords Continental Glacier