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| Geology 370: Glacial Geology
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A.
Introduction
Glaciers
Glacial geology
Importance
Conversion of snow to ice:
melting and refreezing
restructuring by wind
movement of crystals relative to one another
Effective precipitation
nivometric coefficient: ratio of snowfall to total annual precipitation
Temperature
Latitude: important on a global scale
Altitude: important on a local & regional scale
snowline: elevation where annual accumulation & ablation are equal
snowline decreases from tropics towards poles
ice age snowlines lower than today
Topography
Aspect: important on a local scale
lowest snowlines in northern hemisphere on northeast facing slopes
Continentality: distance from moisture source
snowline increases with distance from moisture source
Past: pre-Quaternary glaciations
approximately 280 MYBP (late Carboniferous/early Permian)
approximately 450 MYBP (late Ordivician)
approximately 700 MYBP (late Proterozoic)
Eon
Era
Period
Epoch
Start Date (based on ICS)
Phanerozoic
Cenozoic
Neogene
Holocene
11,800 YBP
Pleistocene
1.806 MYBP
Pliocene
5.332 MYBP
Miocene
23.03 MYBP
Paleogene
Oligocene
33.9 +/-0.1 MYBP
Eocene
55.8 +/-0.2 MYBP
Paleocene
65.5 +/- 0.3 MYBP
Mesozoic
Cretaceous
145.5 +/-4.0 MYBP
Jurassic
199.6+/-0.6 MYBP
Triassic
251.0+/-0.4 MYBP
Paleozoic
Permian
299.0+/-0.8 MYBP
Carboniferous
359.2+/-2.5 MYBP
Devonian
416.0+/-2.8 MYBP
Silurian
443.7+/-1.5 MYBP
Ordovician
488.3+/-1.7 MYBP
Cambrian
542.0+/-1.0 MYBP
Proterozoic
Most recent ice age
Image credit: Natural Resources CanadaPresent
