10 3 Erosion and Deposition by Ice What

10. 3 Erosion and Deposition by Ice

What does a glacier look like? Why are glaciers often called “rivers of ice”?

Glacier § An enormous mass of moving ice. § Continental glaciers – spread across continents. § Alpine glaciers – form in mountainous areas.

How Glaciers Move § § § Gravity causes glaciers to flow. Thick glaciers move faster. Steeper slopes cause glaciers to move faster.

How are glaciers an example of water shaping a landscape? Glaciers are made of snow and ice, which are forms of water. Glaciers shape and change the landscape as they move across it.

Landforms Created by Glaciers § Cirques – bowl shaped depression where glacial ice cuts back into the mountain walls.

Landforms Created by Glaciers § Horns – sharp, pyramid-shaped peaks that form when three or more cirque glaciers erode a mountain.

Landforms Created by Glaciers § Aretes – jagged ridges that form between two or more cirques that cut into the same mountain.

Landforms Created by Glaciers § U-shaped valleys – a glacier erodes a river valley forming a U shape.

Landforms Created by Glaciers § Hanging valleys – small glacial valleys that join the deeper main valley; forms waterfall after the ice is gone.

Glaciers

Types of Glacial Deposits § Glacial drift – all material carried and deposited by glaciers.

Type of glacial drift § Till – unsorted rock material that is deposited directly by the ice when it melts. § Unsorted – till is made up of rock of different sizes.

Type of glacial drift § Moraines – § form along the edges of glaciers § Form when glaciers carry material to the front of and side of the ice.

Type of glacial drift § Stratified drift – a glacial deposit that is sorted into layers based on the size of the rock material.

Outwash plain § A broad area where the glacier deposits streams of sorted material.

Kettle § A depression formed when ice melts and sediment builds up around the block of ice. § Commonly form lakes or ponds.

How is glacial drift related to glaciers reshaping landscapes? Glacial drift is the rock material carried and deposited by a glacier. As a glacier moves, it reshapes the landscape by picking up and depositing glacial drift.

Review Questions 1. What is a glacier? A glacier is an enormous mass of moving ice. Continental glaciers are very large and tend to expand across entire continents. Alpine glaciers are smaller and form in mountainous regions. 2. Identify five landscape features that are formed by alpine glaciers. Five landscape features formed by alpine glaciers include horns, cirques, aretes, hanging valleys, and U-shape valleys.

3. How can a glacier deposit both sorted and unsorted material? Meltwater streams that flow through a glacier carry sorted material. Unsorted material is deposited when a glacier melts entirely. 4. Why are glaciers such effective agents of erosion and deposition? Glaciers are effective agents of erosion and deposition because they are very heavy and have the ability to move across Earth’s surface. Glaciers are capable of eroding, moving, and deposit in large amounts of rock material. .