Lesson 11 Flashcards
What forms in the brittle ice of glaciers?
crevasses
Shallow wetland that typically form after rainfall?
Playa lakes
What are two things about plate tectonics that could have caused glaciation?
- Continents arranged differently
2. Changes in oceanic circulation
What important mechanism of glacial movement consists of the whole ice mass moving along the ground?
Slipping along the ground
Ridge line come together to form a point ?
Horn
What glacial drift is relatively well-sorted sediment laid down by glacial meltwater?
stratified drift
How do Glacier form?
compaction and recrystallization of snow
What is associated with variations in earths orbit
Changes in climate over the past several hundred thousand years
What is the axis wobbling called?
Precession
What is the angle of earths axis called?
Obliquity
What do glaciers show about the flow?
shows the past and present flow
What does milankovitch’s theory say about earths orbit ?
The shape of earths orbit varies
A u shaped valley with steep, straight sides and a flat or rounded bottom.
Glacial trough
a valley which is cut across by a deeper valley or a cliff.
Stream drops straight down.
Hanging valley
What cycles are Glaciers a part of?
hydrologic cycle
rock cycle
Moraine formed between two valley glaciers that have joined?
medial moraine
How much of earths land are was covered during the ice age ?
30%
What is it called when below about 50 meters, pressure is great, causing ice to flow like a plastic material.
Plastic flow
What is the balance or lack of balance between accumulation at the upper end of the glacier, and loss at the lower end called?
glacial budget
Alluvial fans, playas, and playa lakes are features often associated with these landscapes.
Alluvial fans
Playas
Playa lakes
Glacier erosion by lifting pieces of bedrock out of place?
plucking
What zone is the area where a glacier forms with snow accumulation and ice formation?
Zone of accumulation
How many basic cycles in the Earth system are Glaciers a part of?
two
Many of the landscapes of the Basin and Range region of the ______ and ______ United States are the result of streams eroding uplifted mountain blocks and depositing the sediment in interior basins.
western and southern
Where is the zone of fracture located?
Uppermost 50 meters
What glacial drift is unsorted sediment deposited directly by the ice?
till
What type of abrasion erosion causes pulverized rock?
Rock flour
a long, narrow, deep inlet of the sea between high cliffs?
Fiord
What are the two movements of glacial ice?
Plastic flow
Slipping along the ground
What is the effect of ice age glaciers? (Water)
Changes in sea level
Where is wind erosion more significant?
dry areas
What are the two distinct types of glacial drift?
till
stratified drift
What is the shape of earths orbit called?
Eccentricity
What are the two ways glaciers erode land?
plucking
abrasion
What does milankovitch’s theory say about the earths axis?
the angle changes
The axis wobbles
What type of glacier exists on a much larger scale, covering most of Greenland and Antarctica?
Ice sheets
What is responsible for most of the erosional work in a desert?
Running water
other glacial depositions
study pics may has
a half-open steep-sided hollow at the head of a valley or on a mountainside
Cirque
Where is ice brittle in a glacier?
Zone of fracture
What is the effect of ice age glaciers? (Living things)
Plants and animals migrate
What two things must a theory of glaciation causes include?
Cooling of earth
Short term climate changes
What is any sediment of glacial origin called? .
drift
What is a thick mass of ice that forms over land?
glacier
What is the most widespread features created by glacial deposition?
Moraines
Ridge line between 2 valleys
Arte
What type of abrasion erosion causes grooves in the bedrock?
Striations
Moraine which mark the former position of the front of a glacier?
end moraine
What is the division of geological time called?
Pleistocene epoch
What are the 2 types of main glaciers and 2 other ones?
Valley or Alpine
Ice sheets or Continental
Ice caps
Piedmont
What is the main role of wind in a desert?
transportation and deposition of sediment
Glacier erosion by grinding and scraping of a rock surface?
abrasion
Moraines associated with valley glaciers and ice sheets?
end moraine
ground moraine
A fan-shaped mass of alluvium deposited as the flow of a river decreases in velocity?
Alluvial fans
Between the two glacial drifts, which is well sorted sediment and which is unsorted sediment?
well sorted: stratified drift
unsorted: till
A dry, vegetation-free, flat area at the lowest part of an undrained desert basin?
Playas
Moraine formed along the sides of the valley?
lateral moraine
What is the effect of ice age glaciers? (Weather)
Climatic changes
What are boulders embedded in till?
Glacial erratics
What is the effect of ice age glaciers? (Earths layers)
Rebounding upward of the crust?
Practically all desert streams are dry most of the time and are said to be _____.
ephemeral
Moraines only associated with valley glaciers?
lateral moraines
medial moraines
When did the ice age begin?
2-3 million years ago
Layers or ridges of till created by glacial deposition?
Moraines
What are the two types of abrasion erosion from a glacier?
Rock flour
Striations
Name two of the proposed causes of glaciation?
Plate Tectonics
Variations in earths orbit
What zone is the area where there is a net loss due to melting?
Zone of wastage
What type of glacier is found in mountain areas ?
valley or alpine glaciers
Moraine with an undulating layer of till deposited as the ice front retreats?
ground moraine
What type of glacier usually follows valleys that were originally occupied by streams?
valley or alpine glaciers
