Ch. 5 Glaciers & Ice Ages p. 124-140 guided notes

Glaciers: a part of two basic cycles in the Earth system Glaciers are a part of both the ________ cycle and _________ cycle Glacier Definition:

Glaciers: a part of two basic cycles in the Earth system 2 Types of glaciers 1) Valley, or alpine glaciers: _______________________________ _________________________________ 2) Ice sheets, or continental glaciers __________________________________ Other types Ice caps and piedmont glaciers

What kind of Glaciers cover these regions What kind of Glaciers cover these regions? How are they different than the other type?

How Glaciers Move 2 Types of glacial movements Zone of fracture Plastic flow: ___________________________ Slipping along the ground: _________________ Average rate of movements very slow up to ______ m a day Zone of fracture Uppermost _____ meters ____________form in brittle ice

Explain…where is it moving fastest? Why does it fracture on top?

Glacial Movement Glacial Budget: _____________________ ___________________________________ Zones of a Glacier Zone of accumulation – Zone of wastage –

What causes the glacier to advance or retreat? Figure 6.6

Glacial Erosion Glaciers erode by __________ – lifting of rock blocks Abrasion: ___________________ Evidence of Abrasion: _______________ ________________

Glacial Erosion: Erosional Landforms Landforms created by alpine glacial erosion: define and describe how formed Glacial trough/U-shaped valley:_________ Hanging valley: _________________ Cirque: _____________________ Arête:__________________ Horn:___________________ Fjord:___________________________

Label the Erosional landforms created by alpine glaciers Figure 6.9 C

What causes glaciers to deposit material?

Glacial Erosion: Depositional Features Types of glacial drift (sediment of glacial origin) ______ – material that is deposited directly by ice _______________ - sediment deposited by meltwater Glacial erratics: ______________________

What evidence is there that this is glacial till and not river deposited sediment? Close up of pebble

Glacial Erosion: Depositional Features Moraines :_________________________ How are each of the following formed? Types of moraines Lateral Medial End Ground

Glacial Erosion: Depositional Features Define and explain the formation of each depositional feature Outwash plain Kettles Drumlins Eskers Kames

Label the depositional features Figure 6.18

A drumlin in upstate New York… What might you look for on a topographic map of Wellesley to determine if we had any drumlins?

Glaciers of the Ice Age Alternative explanations given for glacial sediment:_______________________ _________________________ Glacial/interglacial cycles occur every __________ Our “Ice age” contained about _____ cycles Ice Age Began 2 to 3 million years ago Division of geological time is called the __________epoch Ice covered ______ of Earth's land area

Maximum extent of ice during the Ice Age: How do we know? Figure 6.19

Causes of Glaciation Proposed possible causes Plate Tectonics which could cause a climate shift by ______________________ ___________________________________ _____________________________ Variations in earth’s orbit which could cause a climate shift by______________________ ______________________________________

Variations in earth’s orbit ________________ hypothesis Shape (____________) of Earth's orbit varies Angle of Earth's axis (___________) changes Axis wobbles (_____________) Changes in climate over the past several hundred thousand years are closely associated with variations in Earth's orbit