glaciation (how glacier ice is formed (3.as more snow falls and the firn…
how glacier ice is formed
1.fist snow falls and as more snow falls, it becomes compact and the air content is reduced.
2.it is important that snow falls on a north facing slope (or south facing if it is in the southern hemisphere) so that it survives a summers melt season. this is then known as firn
3.as more snow falls and the firn is compacted even more, the firn will become glacier ice.
this takes around 50 years
glacial/ interglacial periods
inter-glacial periods last around 10,000 years and we are in one now
glacial periods last around 100,000 and the last significant ice cover over the UK was round 18,000 years ago
types of glaciers
a sheet glacier is a very large moving mass of ice that covers a vast area of the earths surface.
found in places like Antarctica, Scandinavia and Iceland
lie over the top of mountains
moving masses of ice that replaces rivers and lie in valleys
found in mountainous regions such as the alps and himalayas
are held in by the mountains
glacier mass balance
accumulation happens at the bottom of the glacier as this is where the ice accumulates
when the accumulation is greater than the ablation
ice melts at he bottom of the glacier and it appears to be going up the mountain
when ablation is greater than accumulation
Erosion and deposition