week 8 Lecture 2 Flashcards
What are the numbers?
- deglacation
- Last glacial maximum
- Millennial scale climate events
What are 1-4?
- bolling allerod
- Antartic cold reversal
- younger dryas
- heinrich stadial
When did north america’s ice begin too melt?When did it disapeer?
The North American ice sheets began to melt around ~16,000 years ago and had disappeared by ~6,000 years ago.
Why did proglacial lakes form?
Ice sheets had depressed the land beneath
Meltwater from ice sheets poured into these depressions
How do proglacial lakes change with retreat of glaciers?
Position of proglacial lakes moved north through time, as exposed land slowly rose, and new derepressed land was exposed from ice retreat
Whyd did the Channelled scablands form?
Sometimes, proglacial lakes would burst, leading to flooding of immense proportions.
When did the Antartic cold reversal happen?
Occurred ~14,700 – 13,000 years ago
What was the Antarctic Cold Reversal?
Cooling strongest in the South Atlantic and regions south of 40° S
result of enhanced northward heat transport, amplified by the expansion and thickening of sea ice in the southern ocean
What dis the Antarctic Cold Reversal align with?
Aligns with the Bølling Allerød warm stage in the North Atlantic
When did the Youngers Dryas occur?
Occurred ~12,900 to 11,500 years ago.
What happened at the end of the younger drys?
Greenland temperature rose 10°C
one of the most abrupt climate changes in Earth’s history
What happened in the Youngers Dryas?
Northern Hemisphere suddenly returned to near glacial conditions
Expansion of cold tolerant vegetation in Europe
Cooling of SST in North Atlantic and Caribbean
Weakening of Monsoon systems in Asia
Antarctica was warming
What caused the Younger Dryas?
Influx of glacial meltwater into North Atlantic due to bursting of lake agassiz
When did the fastest warming occur?
Bølling Allerød in Greenland (14,500 years ago).
