glacial landform
TRANSCRIPT
Evidence for GlaciersEvidence for GlaciersErraticsErraticsStriationsStriationsPolished BedrockPolished Bedrock
Erratic
ErraticErratic Boulder-sized rock Boulder-sized rock
dumped by a dumped by a glacierglacier
Rock is different Rock is different type than type than surrounding rockssurrounding rocks
Striations
Striations/ Chatter marksStriations/ Chatter marks Grooves carved Grooves carved
into bedrockinto bedrock Formed by Formed by
abrasive action of abrasive action of cobbles and cobbles and pebbles carried at pebbles carried at bottom of glacierbottom of glacier
Direction of Direction of scratches shows scratches shows direction glacier direction glacier movedmoved
Glacial polishGlacial polish Smooth rock Smooth rock
surfacessurfaces Created as glaciers Created as glaciers
flow over bedrockflow over bedrock
Glacial Pavement….Glacial Pavement….
Luis María Benítez.
Source unknown
ZONE OF
ACCUMULATION
ZONE OF
ABLATION
The Upper Grindelwald Glacier and the Schreckhorn, in the Bernese Oberland, Switzerland.
Adrian Pingstone
crevassecrevassessA great fissure or A great fissure or
crack in a glacier.crack in a glacier. They can be more than 30 m deep They can be more than 30 m deep
The Perito-Moreno Glacier, Argentina
TOP LAYER OF GLACIER CAN FRACTURE…..BRITTLE BEHAVIOR
FROMS CREVASSES
http://www.chmouel.com/geeklog/gallery/gallery_individual.php/argentina/8.html
Original valley (V-shaped)
Glaciers come and alter landforms
Glaciers retreat and newfeatures appear
Landscape Features- Landscape Features- Valley GlaciersValley Glaciers
CIRQUESCIRQUES: : semi-circular shaped bedrock feature semi-circular shaped bedrock feature created as a glacier scours back toward the mountaincreated as a glacier scours back toward the mountain
ARÊTESARÊTES: : steep-sided, sharp-edged bedrock ridgesteep-sided, sharp-edged bedrock ridge formed by two glaciers eroding away formed by two glaciers eroding away
on opposite sides of a ridgeon opposite sides of a ridge
CIRQUE
TARN
TARNS:TARNS:glacial lakes glacial lakes produced by glacial scouringproduced by glacial scouringoften found in cirquesoften found in cirques
HORNSHORNS:: 3 or more cirques adjacent to one 3 or more cirques adjacent to one
anotheranother
Hanging Valley
ARÊTE CIRQUE
HANGING VALLEY
U-SHAPED VALLEY
U-shaped valley
tilltillUnsorted and Unsorted and unstratified rock unstratified rock material deposited material deposited dirtectly by glacial dirtectly by glacial ice.ice.
Landforms made from Landforms made from glacial till are called glacial till are called moraines. moraines.
Glacial till sediment, in some places hundreds of feet thick, covers most of New York State.
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All the ‘stuff’ that’s pushed out of the way by the glacier gets piled up in a big heap,
called moraine.
Terminal moraine
Lateral moraine
Medial moraine
Lateral moraine
Dirk Beyer
Lateral moraine
Image by Michael Collier
Medial MoraineMedial Moraine
MorainesMoraines Chugach Chugach
Mountains, Mountains, AlaskaAlaska
Image by Bruce Molnia, Terra
Photographics
MORAINESMORAINES: material left behind : material left behind when glacier recedeswhen glacier recedes
Kettle Lake
Till
Drumlins
Terminal MoraineGlacial Stream
Moraine-dammed lake
Outwash
plain
Esker
Drumlin
drumlins
Kettle Lakes
eskereskerA long, winding A long, winding ridge formed ridge formed when sand and when sand and gravel fill gravel fill meltwater meltwater tunnels tunnels beneath a beneath a glacier.glacier.
Eskers
kamekame A small, cone-A small, cone-shaped hill of shaped hill of stratified sand stratified sand and gravel and gravel formed at a formed at a glacial front by glacial front by meltwater meltwater carrying carrying sediment off sediment off the glacier’s the glacier’s surface.surface.
http://www.env.duke.edu/eos/geo41/gla2.htm
KAME (WISCONSIN)
Have sorted sediments
outwashoutwash
When a When a glacier glacier melts, melts, its rock its rock load load remains remains in nearly in nearly the the same same place as place as in the in the glacier.glacier.
Outwash plainOutwash plainAn outwash An outwash plain will be plain will be crossed by crossed by many many meltwater meltwater streams. streams.