39 terms

Glaciers-2

Glaciers information for Science Olympiad 2012-2013
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glacier
moving body of ice that forms from the accumulation and compaction of snow
sublimate
process in which a solid changed directly into a gas
firn
well-packed snow that survives a summer melting season
snowline
the lowest topographic limit of year-round snow cover
Alpine glaciers
confined by surrounding bedrock highliands
cirque glaciers
create and occupy semicircular basins on mountainsides, usually near the heads of valleys
valley glaciers
flow in preexisting stream valleys
ice caps
form at the tops of mountains
piedmont
foot of the mountain glacier - begins as a confined alpine glacier but then flows onto an adjacent lowland where, unconfined, it spreads radially
glacial period
during an ice age, climatic fluctuations cause glaciers to grow and advance
interglacial periods
Periods of time lasting thousands of years that are characterized by relatively warm air temps. And high sea levels. alternate with glacial periods.
Quaternary ice Age
ice age that happened recently
continental ice sheet
a glacier that moves out from a central point in all directions and covers most of a continent
Budget of glacier
-difference between the glacier's annual gain of snow and ice
-if budget is positive, the glacier will grow
-if budget is negative, the glacier will recede
zone of accumulation
The part of a glacial system where snow and ice are accumulating faster than they are melting away.
zone of ablation
the area low on the glacier where melting exceeds the added snow
equilibrium line
the place on a glacier where snow accumulation and melting are in balance
calving
process by which a block of a glacier breaks off and falls into the sea to form an iceberg
terminus
the end or outer margin of a glacier
drumlin
A low oval mound or small hill
esker
A long ridge of gravel and other sediment, deposited by melt water from a retreating glacier or ice sheet.
kettle lake
A kettle is a shallow, sediment-filled body of water formed by retreating glaciers or draining flood waters.
medial moraine
moraine that forms along the sides of glaciers stirght down
terminal moraine
A moraine deposited at the point of furthest advance of a glacier or ice sheet.
ice shelf
A floating sheet of ice permanently attached to a landmass.
iceberg
A large floating mass of ice detached from a glacier or ice sheet and carried out to sea.
tarn
A small mountain lake.
out wash plain
plain formed of glacial sediments deposited by melt water out wash at the terminus of a glacier.
glacial erratic
a piece of rock that differs from the size and type of rock native to the area in which it rests
cirque
A half-open steep-sided hollow at the head of a valley or on a mountainside
fjord
A long, narrow, deep inlet of the sea between high cliffs
glacial striation
scratches or gouges cut into bedrock by glacial abrasion.
horn
sharply pointed mountain peak which results from the cirque erosion due to multiple glaciers diverging from a central point.
piedmont glacier
A permanent layer of ice covering an extensive tract of land.
ice sheet
A permanent layer of ice covering an extensive tract of land.
aretes
A sharp mountain ridge.
kame
A steep-sided mound of sand and gravel deposited by a melting ice sheet.
hanging valley
A valley that is cut across by a deeper valley or a cliff.
Lateral moraine
moraine that forms along the sides of glaciers side to side