glacial environment Flashcards
slow mobing mass or river of ice
glacier
relatively small glaciers which occur at higher elevations in mountains
alpine glaciers
largest type of glaciers occupying more than 50,000 km sq of land
ice sheet
thick suspended platform of ice on water attached to land
ice shelves
glaciers occupying a hallow bowl shaped epression
cirque glaciers
steams of flowing ice that are confined within steep valley
valey glaciers
a valley glacier extending down to sea level and carves a narrow valley
fjords
a covering of ice over a large are below 50,000 km sq.
ice cap
ice is at temperature near its melting point
temperate glaciers
ice always maintain a temp below its melting point
polar glaciers
5km, elevation above which snow can form and remain present throughout the year
snowline
zone where addition of snowfall, compaction, and recrystallization occurs
accumulation zone
zone where the loss of mass resulting from melting occurs
ablation zone
meltwater at base of glaciers reduces friction by lubricating the surface and allowing the glaciers to slide
basal slip
process by which glaciers flow as grains of ice deform under pressure and slide over each other
internal plastic flow
occurs when accumulation rate exceeds the ablation rate
glacial advancing
accumulation rate is less than the ablation rate
glacial retreat
modification of land surface by the action of glaciers
glaciation
glacier flows over a fractured bedrock surface, it loosens and lifts blocks of rocks
plucking
ice and its load of rock fragment slide over bedrock, acts like a sand paper it smooth and polish the surface
abrasion
sharp crested serrate rdiges
aretes
angular, sharply pointed mountain peak which results from cirque erosion
horns
valley with a characteristic u-shaped, with steep, straight sides and rounded bottoms
U-shaped valleys
a valley elevated above another valley
hanging valley
small mountain lake
tarns
one of a series glacial lakes connected by a single stream
paternoster lake
shallow sediment-filled body of water formed by retreating glaciers or draining floodwaters
kettle
all sediments deposited as a result of glacial erosion
glacial drift
materials deposited directly by glaciers
till
till undergone diagenesis and turned into a rock
tillite
glacially deposited rock or fragments that now rests on a surface made of different rock
erratics
unsorted chaotic deposits deposited on the sea floor or lake bed
glacial marine drift
accumulation of till carried or deposited by a glacier
moraines
unsorted materials left beneath the glacier when the ice melts
ground moraines
tills deposited along the sides of a mountain glacier
lateral moraines
two valley glaciers meet to form a larger glacier
medial moraines
small ridges of till deposited at the elading age of a melting glaciers
terminal/end moraines
glacial drift can be picked up and moved by melt water streams whhich can then deposit thatmaterial
stratified drift
irregular shaped hill or mound composed of san, till, and gravel
karnes
plain formed of glacial sediments deposited by meltwater outwash at the terminus of a glacier
outwash plain
