1. Glacial Processes • Glaciers are large masses of ice that move over time

2. On the basis of size and shape, glaciers can be divided into two types: • Valley glaciers – Glaciers that flow down well defined stream valleys in mountainous regions

3. Continental glaciers – Large ice sheets that cover most of a continent and flow independent of topography

4. There are two main zones of a glacier: • Zone of Accumulation – Here snow and ice accumulate and flow toward the: • Zone of Ablation – Snow and ice are lost through melting, sublimation, and calving

5. If accumulation > ablation, glacier advances • If accumulation < ablation, glacier retreats • If accumulation = ablation, glacier remains a constant size

6. As glaciers move they erode and transport sediment and rock. This creates several different types of erosional and depositional features and distinct water bodies. Common features include: - Cirques - Lateral Moraines - Glacial Striations - Terminal Moraines - Erratics and Till - Lateral Moraines - Drumlins - Kettles

7. Glacial Till Glacial Striations Drumlin

8. Lateral Moraine (dark brown running from center to lower left) Formation of a kettle

9. Glacier development is influenced by climate changes, which can be attributed to three astronomical cycles

10. During warmer periods, glaciers retreat (melt), causing sea-level to rise • During cooler periods, glaciers advance, causing sea-level to fall • If all of the ice on Earth melted (25 million km3) sea-level would rise 65 meters