Goegraphy glaciation Flashcards
What is plucking?
plucking is the pulling of rock from the ground by ice
5 point explanation on plucking
the weight of a glacier cracks the ground underneath it
friction melts the ice at the base of the glacier
this meltwater trickles into the tracks
it refreezes in the cracks and sticks to the glacier
the glacier moves forwards and plucks out rocks and carries them away
what is abrasion in glaciation?
is the grinding of rocks against the landscape by the glacier
the 3 points of abrasion in glaciation
rocks are plucked from the ground and carried along at the base of the glacier
they scrape and scut the ground, acting like sandpaper
this leaves scratches in the ground called striation
these show us the direction the glacier moved
what is an ice sheet in glaciation
melted glaciers formed to make ice sheets
climate definition in glaciation
pattern of weather
lowland areas and glaciation definition
ice sheets can extend into lowland regions, which are typically free of ice today. These ares experience significant glacial erosion + deposition
Glaciers definition
rivers of ice
ice age definition
was a period of time where a third of the earth was covered in ice
glacier definition
massive bodies of slow moving ice
cirque definition
a cirque is a basin-shaped hollow mountain it looks like an arm chair. It has three steep sides and often contains a lake, a cirque was the birthplace of a glacier
3 points of how a cirque is formed
a cirque is formed when snow accumulates in a hollow high up on a mountain. The snow is compressed to form ice
The ice plucks rocks from the sides of the mountain as it begins to move. These rocks make the hollow deeper through the process of abrasion
The ice eventually overflows from the hollow and gravity causes the ice to move downhill. The ice that is left behind melts and forms a lake in the hollow. This lane is called a tarn
U shaped valley explanation 3p
when a glaciers moves out of a cirque and down the mountain, it follows the easiest route possible. This route is often a U shaped valley that has previously been carved out by a river
plucking/abrasion reopen the valley =U shaped valley instead of V shaped valley
glacier moves through valley = cutting off tips of interlinking spurs created by river creating truncated spurs
Ribbon lake definition
is a long narrow lake on the floor of a U shaped valley
paternoster lake definition
when a number of ribbon lakes join together by a river they are called paternoster lakes because they resemble rosary beads
