glaciation Flashcards
what is a glacier?
a mass of ice formed by the accumulation and compaction of snow
how are glaciers created?
hundreds of meters of snow accumulates, and the bottom of the pile compresses into ice
what does it mean when a glacier advances?
rate of accumulation > rate of melt
what does it mean when a glacier retreats?
rate of accumulation < rate of melt
what does it mean when a glacier is stationary?
rate of accumulation = rate of melt
what is a valley glacier also known as?
alpine glaciers
valley glaciers move from ______ to _______ elevations due to gravity
high / low
what happens if the valley opens onto flat land?
the glacier spreads out
how and why do the glaciers move?
outwards under their own weight in all directions
how do glaciers change the landscape?
they scrape the land, loosening rock and soil which becomes part of the glacier.
the glaciers scrape so hard that they leave marks on the earth
what is a drumlin?
an oval shaped hill made of glacial deposits
what is an erratic?
a large boulder that was picked up by a glacier and deposited far from its original surroundings
what is an ice cave?
an opening in the front of a glacier that is formed when glacial ice melts
what is an ice floe?
a large sheet of free floating ice
what is an ice shelf?
a large sheet of ice attached to a glacier or to land but extends into the ocean
what is a lateral moraine?
a mounded glacial deposit at the bottom of a valley
what is a striation?
grooves in rock made by passing glaciers
what is a terminal moraine?
a glacial hill deposit that marks the end of a glacier’s forward movement
