Glaciated Landscapes Flashcards
what was the time period for the Pleistocene
2 million- 11,500 years ago
How many years ago did the Quaternary period start
2.6 million years ago
what are the four types of cold environments
polar, alpine, periglacial, glaciers
what is the average annual temperature in a polar environment
-30 to -40 degrees
18,000 years ago was the last glacial maximum, what was its name
Denvensian
the last UK glacial advance was 12,000-10,000 years ago, what was its name
Lock Lomond Stadial
what period was the Little Ice Age
1550-1750
Eccentricity of the Earth’s orbit changes over a period of how many years
100,000
axial tilt of the Earth varies between which angles
21.8 - 24.4
the Earth wobbles on its axis over a period of how many years
21,000
what is the average size of an ice sheet
10,000 - 100,000 sq.km.
surging glaciers can flow up to what distance per day
100m
what % of all current glacier ice is contained in Antarctica
85%
the Greenland ice sheet consists of how much of the Earth’s total ice cover
11%
for every 100m in altitude, how much does the temperature decrease by
1 degree
what is roughly the average amount of precipitation that periglacial environments receive each year
600mm
how long do subsoil temperatures have to remain below 0 degrees, before they are considered permafrost
2 years
what % of the Earth experiences periglacial conditions
20%
how much % of land cover does sporadic permafrost cover
less than 50%
what is the range of height that pingos can reach
30-70m
what are the names of the two types of pingo
open system and closed system
ice-wedge polygons are usually found where
valley floors
what % of Canada is covered by some form of permafrost
over 50%
what % of Alaska is covered by permafrost
80%
blockfields can be found in which area of Canada
Northern Manitoba
the transformation from neve/firn to glacier ice can take up to how many years in polar regions
150 years
the overall transformation of ice can take what time frame
100- 4000 years
the Greenland ice sheet covers how much of an area
1.7 million km2
how thick is the Greenland ice sheet in the centre
3km
what % of the world’s ice masses are experiencing ‘rising trends’ in their net negative balances
75%
basil slip is divided into three processes, name them
creep and regelation, extending and compressing flow; surges
what is formed on top of a glacier through rotational ice movement
Bergschrund
rock flour is made up of what grade size
0.1mm
a pyramidal peak can be found between how many cirques
three or more
an Arete is a sharp ridge between how many cirques
2
macro-scale landforms are how big
1km or greater
micro-scale landforms are how small
less than 1m in length
material deposited underneath ice is known as what
Till
till that is transported and deposited in a different geological area is known as a what
An erratic
name the four different types of moraine
medial;lateral;recessional and terminal
a Drumlin resembles the shape of a what
oval/egg
the erratic boulders transported by the Cordilleran Ice sheet to the plains of Alberta weigh up to how much
16,000 tonnes
what are the two types of fluvioglacial landforms
ice contact and pro-glacial
