Glaciers 2 Flashcards

Terms Definitions
plucking
lifting of rocks
WisconsinanIllinoianPre-Illinoian
stages of glaciation in illinois
ABRASION produces:
striations and rock flour
Cirque
an amphitheater-shaped basin at the head of a glaciated valley
LANDSCAPES PRODUCED BY ALPINE GLACIATION (valley glaciers)
HANGING VALLEYS
CIRQUE
TARN
HORN
ARETES
Truncated Spurs
eroded triangular shaped cliffs in glaciated valleys
Horns
Mt. Russell and Mt. Carillon are pyramid-like in form. They were produced by the head ward erosion of glaciers that once occupied the valleys that nowsurround them.
Two continents that contain continental glaciers
Antartica and Greenland
MORAINE
specific types of till deposits that occurs on a glacier or left behind by a
glacier
apart of two basic cycles
-hydrologic cycle
-rock cycle
Hanging Valley
a tributary that enters a glacial trough high above the floor of the trough
Rigid Zone
Occurs above the zone of plastic flow.
What are drumlins?
Long, smooth, canoe-shaped hills made of till. Usually found in swarms. Formed when a glacier ran over a preexisting moraine.
What is a hanging trough?
A tributary glacial valley.
PLASTIC FLOW
- movement that occurs within a glacier(does not move at base)
landforms created by erosion
Landforms created by glacial erosion
Erosional features of glaciated valleys
Glacial trough
Hanging valleys
Pater noster lakes
Cirques
Fiords
Arêtes
Horns
zone of accumulation
the area where a glacier forms
Elevation of the snowline varies greatly
Ice Age
Occured 1.6 or 1.8 million to 10,000 years ago during the Pleistocene Epoch.
U-shaped valleys
Valleys that were once occupied by a glacier.
What is firn?
A rough, granular ice material found in a glacier.
Sediment produced by glaciation is ____
- ANGULAR, MULTI-SIZED, UNSORTED
Eccentricity of orbitChanges in earth’s tiltPrecession of the equinoxes
the 3 parts of Milakovitch's Theory
What are glacial deltas?
Formed when glacial streams empty into lakes.
landforms made of stratified drift - ice contact deposits
Ice-contact deposits
Deposited by meltwater flowing over, within, and at the base of motionless ice
Features include
Kames
Eskers
What is a terminal moraine?
The deposit from the glaciers farthest advance.
What is rock flour?
A mixture of fine sand and silt formed by the crushing of rock under a glacier.
LANDSCAPES FORMED BY CONTINENTAL GLACIATION
- do not form rugged topography like alpine glaciers
- form rounded topography
- form grooved, striated bedrock and rounded elongated mountains
What are the different sections of a glacier?
The top 30-40 m are brittle (crevasses can form). The rest is called plastic. It is so dense that it is extremely hard(about a 5 on Mohs scale).
Marine
ocean
roches moutonnees
sheep rocks
Drumlins
- Smooth, canoe/tearshaped
hills parallel to
direction of glacial
movement
- Steep side faces the
direction from which
the ice advanced
Till
Unsorted, unstratified material left by glaciers.
Horn
pyramid-like
peak formed by 3 or
more cirques
V-shaped valley
carved by running water
erratic
large boulder transported and deposited by a glacier. Sticks out does not match rocks in area
What is Till
sediments glaciers deposits
decreases
As latitude increases, snowline _______________
Morains
(Glacial deposit) An accumulation of unconsolidated material deposited by glaciers.
rocks dragged along beneath glaciers are...
plucked
Ice Ages
long periods of freezing weather
Glacier
A large, moving mass of ice.
col
[glacial] two eroding cirques may reduce an arete to a saddlelike depression or pass
ice flow in?
all dicection/ ice sheet
Glacier Ice
A type of metamorphic rock
Zone of Fracture
uppermost portion of glacier
Valley Glaciers
glaciers that flow in valleys
Firn
Compacted and refrozen snow that hasn't become a glacier
Eskers
Deposited by rivers, running water; sorted.
Terminal moraine
Glacial till marking the glacier's furthest advance.
Kettles
A steep, bowl-shaped hole in the ground once covered by a glacier, formed when a block of ice left by a glacier melts.
kame
cone-shaped hill of sand and gravel formed by the deposition of sediments in streams flowing over the top of the glacier
Varve
bands of light and dark sediments; summer and winter pattern of deposition (like ogive but of dirt)
Arete
is a jagged saw-tooth ridge formed between 2 adjacent glacial lobes moving to lower elevations
Piedmont
coalescence of two or more Alpine glaciers; usually occupying lowlands
drift
any material carried and deposited by a glacier
alpine glacier
a glacier in a mountain range
cirque glaciers
filled bowl-like hollows. found high on mountainsides
A bowl-shaped depression formed by a glacier in the valley where it begins
cirque
striations
very small scratches found in the bedrock produced by the erosion of a glacier.
ground moraines
deposited as glacier retreats but doesn't stall...mostly flat
ogive
alternative bands of light and dark ice on a glaciers surface
Barchan dune
dunes with a parabolic shape with horns that extend in the same direction as the wind
U; V
glacially eroded valleys have a ____ shape, as opposed to the ____ shape left by stream erosion
kettle lake
pooling of glacial meltwater in holes left by chunks of receding glacier
Types of Sand Dunes
barchan dunes, transverse dunes, longitudinal dunes, parabolic dunes and star dunes
Medial moraines
When two glaciers come together, and their sediments do too, and they are now in the middle instead of on the edge.
Rock Flour
A fine sediment of pulverized rock produced by glacial erosion
glacial till
an unsorted mixture of rock materials deposited as a glacier melts
Continental Glacier
glaciers that cover large areas that form when temperatures remain cold enough to allow snow and ice to accumulate
glacial deposition
where a glacier melts a deposits sediment that it has eroded from the land
positive budget
glacier is advancing, alpine to lower elevations, continental to lower latitudes
basil sliding
glacial slips/slides on a think layer of mud at the bottom of a glacier.
terminal moraines
end moraines that form at farthest edge of toe advance
moulin
a vertical but windy tunnel in a glacier carved by a surface stream
kettle
a small depression that forms when a chunk of ice is left in glacial till
fiord
A glacial valley that has been filled by the sea
Horns?
a pyramid like peak formed by glacial action in 3 or more cirques surrounding a mountain summit.
ice cap
smaller ice sheet , may be in mountains
Medial Moraine
the middle of the ice; form where glaciers join; debris mostly on top of the ice
calving
process by which a block of a glacier breaks off and falls into the sea to form an iceberg
ridged zone
part of glacier where ice stays with itself, doesnt deform much
iceberg
a section of a glacier that flows down a steep gradient so that the ice fractures into numerous crevasses and towering ice pinnacles
Accumulation Zone
highest and coldest part of a glacier where snow buildup occurs
ice ages.
periods of time where all the glaciers are advancing. many ice ages in history of earth only takes a 10 degree drop in temperature to go into the ice age.
Glacier Trough
eroded by passage of valley glacier - longitudinal profile is steep, irregular and stepped - u-shaped and typically straight
Glacial Drift
all sediment deposited as a result of glacial erosion
various landforms
when a glacier melts it deposits the sediment it eroded from the land, creating this
Tarn
A lake high in the mountains in a dip
Describe the trophosphere
*Lowest Layer*Contains 80% of mass of the atmosphere*where weather occurstemperature decreases with height
Icebergs-
a large mass of ice in the middle of an ocean
Zone of Wastage
there is a net loss to the glacier
Glacial erosion: explain proccesses and describe resulting landforms; plucking
Plucking- fracturing and lifting up rock blocks
The Principle of Uniformitarianism
"The Present is Key to the Past"
How do glaciers lose mass?
Ablation (it melts, breaks off)Loss of snow/ ice from melting, calving, sublimation, etc.
Zone of ablation
Where snow / ice is lost due to melting, sublimation, or calving.
Continental Glaciers (Ice sheets)
- Exist on a larger scale than valley glaciers
- Two major ice sheets on Earth are over Greenland and
Antarctica
- Cover large land areas
Two of the Many Hypotheses for the Cause of Glacial Ages Involve...
plate tectonics and variations in Earth's Orbit
Seal level rise associated with ice melting
if melted, sea would rise 60 to 70 meters
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