click below
click below
Normal Size Small Size show me how
Glacier:move,ero,dep
Term | Definition |
---|---|
till | unsorted material deposited by glacier (large) |
stratified drift | Sediments deposited by glacial meltwater that are sorted and layered (small) |
glacial erratics | piece of rock that differs from the size and type of rock native to the area in which it rests. |
glacier | dense ice sheet that slides down a slope due to gravity |
alpine glacier | glacier that started in a bowl shaped mountain cavity (cirque) and flows into a valley |
piedmont glacier | a valley glacier that slides down into a plain |
icecap | covering of ice over a large area |
plastic flow | movement within the ice; beneath zone of accumulation and zone of wastage and zone of fracture |
zone of fracture | Upper 30 - 60 meters ; brittle behavior; the ice breaks rather than undergoing gradual permanent distortion and flow |
zone of accumulation | where snow and ice form; snow accumulates faster than it melts; above equilibrium line; front |
zone of wastage | below equilibrium line; ice and snow melt faster than the accumulate; toe |
crevasse | zone of fracture; caused by tension when when moving over irregular terrain; cracks in ice |
ablation | loss of snow at lower end of glacier (zone of wastage) |
calving | large pieced of ice break off of front of glacier; creates ice bergs |
ice berg | floating pieces of ice |
firn | stage between snow and permanent ice |
glacial retreat | glacier shrinks |
glacial advance | glacier grows |
equilibrium line | where the amount of new snow gained by accusation is equal to the amount of snow lost by abrasion; moves up in the summer and down in the winter |
plucking | meltwater penetrated the cracks and joints along the rock floor of the glacier and freezes; erosion and transportation of large chunks of rock |
abrasion | ice and load of rock fragment slide over bedrock, and smooth, crape, and polish the bedrock; erosion that occurs when the particles scrape against each other |
glacial striations | scrapping of glacier; formed by abrasion |
u-shaped valley | also known as glacial trough |
trough | glacier widen, deepen, and straighten valley, |
hanging valley | after ice has redeemed, valleys of smaller tributary glaciers are left standing above the main glacial trough |
cirque | bowl-shaped depression |
arete | sharpe-edged ridges; line of sharp pyramid like peaks |
horn | pyramid like peak that projects above surrounding |
fjord | steep sided inlets of sea; a long, narrow, deep inlet of the sea between high cliffs |
glacial flour | rock in a powdery form caused by glacial erosion; the bottom go the glacier rubs across the bedrock layer, eroding the softer material |
tarns | mountain lake or pool formed in a cirque excavated by a glacier |
paternoster lakes | one of a series of glacial lakes connected by a single stream or a braided stream system of cirques |
morain | glacially formed accumulation of unconsolidated glacial debris (soil and rock) |
terminal or end morain | farthest advance of glacier(moraine) |
lateral morain | along the side (moraine) |
medial morain | (moraine) 2 valley glaciers intersect to form one ice stream |
esker | remain of river that ran underneath a glacier; winding ridge of stratified sand and grave |
kettles | large piece of ice breaks off a glacier as it moves; leaves depression such as lake |
drumlin | elongated hill in shape of egg; formed from glacier moving over till |