Lecture 7 and 8 Flashcards
How is Marine Isotope Stage 3 different from other odd-numbered Marine Isotope Stages?
It is not interglacial in nature
When was Marine Isotope Stage 4?
71-58 ka
What was the global sea level during Marine Isotope Stage 4
90 meters lower than today
What has happened to most Marine Isotope Stage 4 glacial landforms?
They have been overridden by the Marine Isotpe Stage 2 ice sheets
How was the Cordilleran ice sheet in Marine Isotope Stage 4 compared to Marine Isotope Stage 2?
The southern part had a larger extent
How was the Eurasian ice sheet during Marine Isotope Stage 4 compared to Marine Isotope Stage 2?
It was smaller
What very cold region remained ice-free during the last glacial maximum?
The Arctic Siberia
What does an ice-free Arctic Siberia have to do with human dispersal?
There was a stable plant and animal community that would enable humans to live there, and possibly these conditions could have also enabled human dispersal to the North American continent 10 000 years earlier than previously thought.
How long are the winters in Siberia today?
9 months
How long are the summers in Siberia today?
1 month
What is the only region with similar present-day conditions as the Arctic Siberia?
Arctic Canada
Was Arctic Canada ice-free during the last glacial maximum?
No, it was heavily glaciated
What mechanisms were previously suggested to prevent glacial inception in Arctic Siberia?
A lack of material for ice-sheet build-up (precipitation) and increased dust transport deposited on snow, enhancing snow melt.
Why does dust production increase during glacial periods?
Due to increased erosion by ice sheets and increased aridity
What mechanisms prevented glacial inception in Arctic Siberia during the last glacial cycle?
The topography and height of the North American ice sheets prevented precipitation. Beringia was already covered with ice before LGM.
