Ch. 6 (Taylor) Flashcards
What is the difference between ice sheets and alpine/valley glaciers?
ice sheets: large scale glaciers that can cover entire continents
alpine/valley glaciers: form in mountainous areas at higher elevations
What are the different ways a glacier can move?
plastic flow and fracture/brittle flow
What is plastic flow?
when a glacier moves, the ice deforms and moves without the ice breaking
occurs near the bottom of a glacier
What is fracture/brittle flow?
when a glacier moves, the ice fractures
occurs near the top of the glacier
includes crevasses that open when ice fractures during movement
What are the erosional glacial features that occur?
Plucking: loosening and lifting of solid rock as a result of freeze/thaw action at areas of weakness
Abrasion: scraping against solid rock
What is Cirque?
bowl shaped depression in the zone of accumulation, at the top of the glacier
What is Arete?
glaciated ridges between to troughs
What is Horn?
glaciated peak
What is Fjord?
glacier that terminates at a large water body
List the different types of glacial landforms
cirque, arete, horn, fjord
What are the glacial deposition features
moraines, outwash plains/valley trains, kettles, drumlins, eskers, kames
What are the different types of moraines?
Lateral: sediment built up on the sides of a glacier
Medial: forms when two or more lateral moraines coalesce
End: mound of till found at the terminus of a glacier, represents the farthest advance of a glacier
Ground: subsequent moraines that form as a glacier recedes
Definition of Moraines
layers or ridges of sediments at the edges of a glacier
What is an outwash plains/valley train?
valley where running water deposits glacial drift
What are Kettles?
depressions in glacial till filled with water, where solitary chunks of ice become buried in till, later melt, forming a depression in the till
What is a drumlin?
tear drop shaped hill of till
made by large obstruction that glacier was unable to move
ice direction of movement from head toward tail
What are eskers?
sinus ridges of sand and gravel, formerly a sub-glacial stream
What are kames?
large hill of sand and gravel
made when large depressions in receding glaciers are filled with mounds of stratified drift
How does water play an important role in shaping deserts?
rain often occurs as heavy showers –> causes flash floods –> interior drainage (streams have no drainage pattern) –> desert streams are ephemeral (flow only during periods of rainfall) –> most erosional work in a desert is done by running water
What are the causes of wind erosion?
deflation, blowouts, desert pavement, wind abrasion
