Chapter 14 Glacial & Periglacial Landscapes Flashcards
Glaciers
Large body of ice
continuously moving.
Two Types:
Alpine: Greenland Continental: Antarctica
Glaciers:
Above Snowline
Snow often does not melt entirely
Glaciers:
Below Snowline
Snow melts away during summer
Glaciers:
Firn
Granular ice
Older, partly compacted snow
The result of repeated melting and freezing or snow
Glacial Ice
Compacted firn
Results in very dense ice
Alpine Glaciers
Exist in valleys in mountain ranges
Named after Alps in Europe
Continental Glacier
Ice Sheets
Greenland Ice Sheet Covers almost the entire island and is almost two miles thick Cover vast areas (Example: Antarctica)
Glaciers:
Zone of Accumulation
Upper portion of glacier
Ice is added, and accumulates
Glaciers:
Zone of Ablation
Lower portion of glacier
Ice is removed through:
Melting, Deflation (wind), Calving, and Sublimation. Glacier National Park, MT
Glacial Erosion:
Glacial Plucking
The breaking-off and removal of rock from a glacier.
Glacial Erosion:
Abrasion
The scraping away of rock, by rocks being transported by a glacier
Glacial striations and polish result
Glacial Erractic
Boulder transported by glacier
Ice Ages:
Glacial Period
Period with lower temperatures
Glaciers grow or are created
Sea level drops as water is
incorporated into glaciers
Ice Ages:
Interglacial Period
Currently in an interglacial period
Period with higher temperatures
Glaciers melt and retreat
Sea level rises as glacial meltwater enters ocean
Glacial Erosion:
Drift
Rock material transported by a glacier
Glacial Erosion:
Stratified Drift
Sorted by size
Carried by meltwater
Glacial Erosion:
Unstratified (Till)
Unsorted
Carried by glacier itself, not by meltwater
Alpine Glaciers:
U-shaped valley
Results from glacial
erosion
Example: Yosemite Valley
Alpine Glaciers:
Cirque
Bowl shaped depression near the upper end of glacier
Alpine Glacier:
Arête
Jagged rock wall separating two cirques
Alpine Glacier:
Horn
Jagged peak separating several cirques
Alpine Glacier:
Tarn
A lake that fills a cirque after a glacier has melted
Alpine Glacier:
Paternoster Lakes
Small, circular lakes organized in a
stair-step pattern
Named after rosary beads
Sea Ice
Ice in oceans
Pack ice
Formed from freezing seawater
Icebergs
Body of continental glacier that has broken free to float on water
Thicker than sea ice
Float low in the water
Continental Glacier
A much larger, flatter glacier (ice sheet)
Example: Antarctic Ice Sheet cover entire continent
Pluvial Periods:
Paleolakes
Ancient Lakes
Examples:
- Pyramid Lake
- Mono Lake
The opposite of the accumulation zone in a glacier?
Ablation Zone
