How does glacial ice form? Flashcards
1
Q
1
A
low temperature
2
Q
2
A
- snow falls & stays for one year
- conditions are so cold it doesn’t melt
- this is firn (0.4g/cm3)
3
Q
3
A
diagenesis occurs when new low density (0.5g/cm3) snow falls, layers & compacts with initial snow
4
Q
4
A
- each new snowfall air is expelled
- low-density snow converts to high-density
5
Q
5
A
subsequent years of snowfall = further compaction = glacier ice (0.83-0.91g/cm3)
6
Q
Density of firn
A
0.4g/cm3
7
Q
Snowfall for diagenesis density
A
0.5g/cm3
8
Q
Glacial ice density
A
0.83-0.91g/cm3
9
Q
How long does this take?
A
30-40 and 1000yrs
10
Q
When is true glacial ice encountered?
A
100m deep
