Week 8 LGM Flashcards
When did the LGM occur?
23,000 – 19,000 BP, centred on ~21,000 ka BP
What is the LGM?
defined as ‘peak’ glacial conditions when ice sheets were largest and global temperatures were at a minimum.
When did the last glacial period occur?
115,000 – 11,500 years BP.
What does the LGM mrak?
the culmination of a nearly 100 kyr long glacial
period, during which ice-sheets had continued to build up.
What were the conditions during the LGM
icy, dry, cold, windy and sparsely vegetated
What was the insolation at mx ice sheets?
summer insolation had risen closer
to modern levels
what helped force LGM
Lower CO2
insolation
presence of ice sheets
What where global sea level during LGM?
110-125 m lower than today
How much of the world was covered by ice sheets today and in the LGM?
10% today
25% LGM
Which ice sheet was the largest in NH?
The North American ice sheet (Laurentide and Cordilleran) was the largest accounting for 55%
of the extra ice volume.
What did the presence of large ice sheets impact?
sea level, atmospheric circulation and
vegetation
What are loess fields?
large amounts of dust deposited from a glacier
What did the presence of ice sheets do?
generated large
amounts of dust leading to the formation of loess fields
Why do ice sheets cause more dust?
Ice sheets grind across the landscape, scraping and
dislodging soils, producing large amounts of debris
(boulders to fine clay).
Where did dust in Antarctica come from?
predominantly from Patagonia.
