15.2
What is basal slip?
At the base of the glacier there is increased weight and that weight causes the water to melt Pressure cause ice to change from solid to liquid Can stay as water Can refreeze into slush with with sand and gravel This decreases friction and glacier can "flow" Only the base moves No melt when cold
when and where do glaciers move slowest?
Glacier parts that move the slowest Bottom and sides Friction against the rock slows it down
how do glaciers move?
Glaciers move due to their own weight and the force of gravity Rate of movement varies centimeter per day to meter per day As they move they erode rock
what is the plastic follow movement?
Grains of ice change shape from spherical to flat Because of pressure Ice grains slip over each other propelling the glacier is not touching the ground friction
what is glacial creeping?
Less friction in the middle Middle goes further than the sides Sides have more friction against the edge of a valley
how do glaciers cause erosion?
Rock can be eroded, carried inside or dragged underneath Materials are eventually deposited
what is a cirque?
Semi-circular basin where the glacier began High elevation Glacier flows out of the cirque Ex. Tuckerman's ravine Previous cirque
what is the Jakobshavn Isbrae?
The fastest glacier in the world In 1985 it moved 4.16 miles And it moved 3.54 miles in 1992 In 2000 it moved 5.84 miles And 7.83 miles per year in 2003
How are u-shaped valleys formed?
U-shaped valleys usually are made by glacier Erosion on 3 sides! Continental glaciers cover the whole land so it grinds down the mountains around it to rounded peaks Effects of valley glacier erosion Produce U-shaped valleys Carve out very distinct landforms
when and where do glaciers move fastest?
When the glacier moves fastest In the summer (warm periods) After periods of heavy snowfall Where do glaciers move fastest Steep slopes (gravity) In the middle and center
what is a horn?
a peak that has been partially eroded Ex. Matterhorn Glaciers carve out the base of the mountain, leaving a pointed peak
What is an iceberg
calved off pieces of glacier... fresh water
what is a hanging valley?
formed by a tributary glacier at a higher elevation than its "parent" glacier
what is a lateral moraine?
hen the snow piles up lateral to the glacier's movement
What are striations?
scratch marks left by the glacier's path
what is a moraine?
the accumulation of till
what is an ice front?
the end of the glacier
what is a terminal moraine?
the farthest point the glacier has traveled and the moraine that is found perpendicular to the glacier's flow that marks the furthest point of glacial advancement
what is till?
unsorted rock deposited by a melting glacier
what is calving?
when pieces of the ice front on a continental glacier break off Global warming
what is a crevasse?
when there is a crack in the glacier due to its movement Will open up in a perpendicular direction to the glaciers flow