Glaciers Flashcards
Timeframe of Pleistocene
~2.5 million-11,000 years ago
Global environmental changes during Pleistocene
Ice fluctuated, permafrost, 1/3 of land covered by ice… Lots of lakes
Firn
Granular-like snow that is transitional in transformation of snow to glacial ice; Snow that has persisted through a summer season in the zone of accumulation
Ice Sheets
An enormous, continuous continental glacier/ the bulk of glacial ice on Earth covers Antarctica and Greenland in two ice sheets.
Ice Caps
A dome-shaped glacier, less extensive than an ice sheet, although it buries mountain peaks and the local landscape.
Alpine/valley glaciers
A glacier confined in a mountain valley or walled basin, consisting of three subtypes: valley glacier, piedmont glacier (at base of mountain, spreading freely over nearby lowlands), and outlet glaciers (flowing outward from continental glacier)
Abrasion
Mechanical wearing and erosion of bedrock accomplished by the rolling and grinding of particles and rocks carried in a stream, moved by wind in a “sandblasting” action, or imbedded in glacial ice
Arete
Very sharp ridge separating glacial valleys
Cirques
Origin of glaciers. A bowl shaped recess
Horns
A pyramidal, sharp-pointed peak that results from several cirque glaciers gouging an individual mountain summit from all sides
Till
The direct deposits that appear unstratified and unsorted
Moraines
A marginal glacial deposit of unsorted and unstratified material
Lateral Moraine
Forms along each side of a glacier
Medial Moraine
Forms when two glaciers with lateral moraines join
End Moraine
Formed at other points where a glacier paused after reaching a new equilibrium between accumulation and ablation
