Glaciers, Deserts, and wind

thousands of small glaciers that exist in lofty mountain areas -follow vallyes originally occurpied by streams -longer than they are wide

flow out in all directions from one or more centers

floats on water -cannot change water levels

large, relatively flat masses of ice extending seaward from the coast (eg. ross ice shelf) -thinner seaward

cover uplands and plateaus; much smaller than ice sheets

occupy broad lowlands at the bases of steep mountains; form when one ore more valley glaciers emerge from the confoining walls of mountain valleys

fed by ice caps and ice sheets; flow down valleys; tongues of ice

plastic- movement within the ice; ice behaves as a birttle solid until 50 meters of weight is surpassed

occasional mass movements of glaciers

uppermost 50 meters of a glacier; brittle ice; crevasses form here

form when glacier moves sover irregular terrain, resulting in cracks

snow accumulation and ice formation above the zone of fracture

firn

outer limits of the zone of accumulation

below the snowline; net loss of snow from pervious winter

creates icebergs; glaciers waste as large pieces of ice break off in the front of a glacier

balance between accumulation at the upper end of the glacier and loss at the lower end; if ice accumulation exceeds wastage glacier advances

plucking and abrasion

meltwater penetrates cracks and joints and freezesm sediment becomees part of the glacier’s load

smoothing and polishing of the surface below; pulverised rock called rock flour makes up loess deposits

large rocks in glaciers create grooves in rock below

tirbutary glaciers located above the main glacier after it has melted and begun receding

areas of snow accumulation; bowl-shaped depressions

small lakes found in cirques