G1 Glacial Planet Flashcards
(17 cards)
What is a glacier?
Flow of glacial ice
A glacier forms when snow accumulates faster than it can be removed, eventually turning to ice.
What are the main types of glacial landforms?
- Cirque (corrie) glacier
- Valley glacier
- Outlet glaciers and ice streams
- Tidewater glacier
- Ice caps and ice fields
- Ice sheets
- Ice streams and ice shelves
These landforms represent different ways glaciers interact with the landscape.
Why do glaciers form?
Temperature and moisture controls
Exogenic climate controls influence glacier formation.
Where do glaciers typically form?
High latitudes and high altitudes
Climate and tectonic uplift are the main controls for glacier formation.
When do glaciers and ice sheets form?
Varying extent and causes through time
Historical fluctuations in climate influence glacier formation.
What was the ‘Little Ice Age’?
A period of cooler climate driven by slight fluctuations in solar activity
It led to a notably greater extent of glaciation in temperate regions.
What caused the Greenland Stadial 2 (13-12kya)?
Collapse of northern hemisphere ice sheets
This created a flux of freshwater into the North Atlantic, impacting ocean circulation.
What was the Last Glacial Maximum (LGM)?
Distribution of glaciers at ~30-22ka was x1000 in Arctic Canada, x1500 in northern Europe & x1.3 in Arctic
It represents a time of extensive glaciation.
What are the two major ice masses involved in North America’s glaciation?
- Cordilleran ice sheet
- Laurentide ice sheet
These sheets coalesced and joined with the Greenland ice sheet at LGM.
What is isostatic uplift?
The rise of land masses that were depressed by the weight of ice sheets
It plays a role in estimating the elevation of ice sheets.
How much global sea level rise has occurred since the LGM?
~120m of SLR since LGM
Sea level changes vary locally, demonstrating complexity in relative sea level change.
What characterizes the Eemian interglacial period?
4-6°C warmer than present
It serves as a comparison point for glacial and interglacial cycles.
What is the primary mechanism for controlling temperature on Earth’s surface?
The greenhouse effect
This mechanism has influenced the carbon cycle over millions of years.
What are the conditions for the growth of a continental scale Antarctic ice sheet?
CO2 threshold of 500-750 ppmv
CO2 levels significantly impact ice sheet formation.
What happens to snow in relation to albedo?
Snow -> high albedo -> reflects short wave radiation (SWR) -> cooling
This process affects global temperature and climate patterns.
True or False: The presence of ice sheets on Earth is a common feature of its history.
False
Ice sheets are an unusual feature in the context of Earth’s history.
What initiated the Cenozoic ice age?
The breakup of Antarctica and South America
This event significantly impacted global climate.
