Geology; Chapter 4

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Section 1

Question Answer
The combined area of present-day continental ice shets cover about what percentage of Earth's land surface?10%
The uppermost 50 meters of glacier is reffered to as the zone of_____.Fracture
When ice accumulation equals ice wastage, the front of the glaciaer will _____.Remain Stationary
List four features of valley glaciation.Horn, Fiord, Cirque & Levee
Layers or ridges of glacial till are _____.Moraines
Most of the major glacial episodes of the recent Ice Age occurred during a divsion of geologic time called the _____.Pleistocene epoch
About what percentage of Earth's land surface do dry regions encompass?30%
Most of the erosional work in deserts is accomplished by _____.Running Water
Many arid areas are characterzied by this types of drainage.Interior

Section 2

Question Answer
Two basic types of glaciers are _____ glaciers and _____.Valley ; Ice sheets
The movement of glacial ice is generally refered to as _____.Flow
Glacial sediments, no matter how, where or in what form they were depositied, are called _____.Drifts
_____ moraines form at the terminus of a glacier.End/ Terminal
The two climatic types commonly recognized within the dry regions of the world are _____ or arid, and _____, or semiarid.Desert ; Steppe

Section 3

Question Answer
Deserts: Arid, less than 10 in. per year
Steppes: Semi-arid, 10 to 20 in. per year. More humid transition zone, separating deserts from bordering humid climates.
Ephemeral Streams: carry water only in response to specific episodes of rain fall. Few tributaries, level rises and/or falls quickly.
Interior Drainage: discontinuous pattern of intermittent streams that do not flow into the ocean
Alluvial Fans: cone of debris deposited by stream on land at moth of canyon.
Playa Lake: Temporarily lake at low point in arid, basin, dry
Deflation: wind erosion by lifting and removal of lose materials
Desert Pavement: layer of pebbles and gravel left on surface. Too large to be moved by wind.
Loess (luhs): blankets of wind blown silts, fine particles, occurs world wide
Dunes: wind deposited mounds or ridges of sand
Slip face: steep downwind side of dune
Cross beds: inclined layers in sand dune

Section 4

Question Answer
Glaciers: Think mass of ice forming on land from compaction and recrystallization of snow, that flows
Budget of Glaciers: Advance (grow faster than melts), Retreat(melts faster than grows), Stationary(equal)
Calving: Large pieces break off from of glacier, icebergs form at sea
Zone of Wasting: Region of ice loss, more melts than forms
Zone of Accumulation:Region where snow is accumulates and ice formation occurs at upper end of valley
Crevasses: Deep crack in the brittle surface of a glacier
Zone of Fracture: Upper(top) 50m of ice where cracking is common, not enough pressure for plastic flow
Alpine or Valley Glaciers: A glacier confined to a mountain valley which was often a previous stream valley, many in mountains around the world
Continental Glacier: (Ice sheet) Large thick mass of ice flowing outward from one or more accumulation centers


Section 4.2

Question Answer
Ice Flow: (Glacial movement occurs in two ways)Plastic Flow, Glacial movement
Glacier Eroding: (two types)Abrasion, Plucking
Two Areas where there is Ice Sheets:Greenland and Antarctica

Section 5

Question Answer
Kames: Steep sides hills formed as glacial melt water washed sediments into depression in the
Eskers: Sinuous ridges of sorted drifts deposited by water flowing in and under glaciers (good
Outwash Plain: Ramp like surface of stratified drift built adjacent to downstream edge of end
Kettles: Bowl shaped basin formed when blocks of stagnate ice melt, form ponds
Drum lines: Long low hills formed as glaciers advance over drifts
Moraines: Layers or ridges of till formed by glacial deposition
List four types of Moraines: Lateral- Alongside, Medial- Towards center after 2 valley glacier have joined, Terminal- At end of glacier (farthest Advanced) or recessional, Ground- Under level areas
Drift: General Terms for sediment of glacial origin (Midwest to New England)
Three types of Drifts:Till (unsorted), Stratified Drift(sorted by size), Erratic (boudlers)
Cirque: Bowl shaped basin formed at upper end of valley glacier
Hanging Valley: Tributaries glacial valleys left above the main trough
Glacier Trough: Deeper, Wider, straighter U-shaped Valley, made by glaciers
Tarn:Lake in Cirque
ArĂȘtes: Sharp edges between Alpine glacial valleys
Horn: Pyramid like peaks formed by glacier (ex: Swiss Matterhorn)
Fiords: Deep, Steep inlets of the sea, forms in flooded glacial troughs
Glacial Lake Evidence of many glacial cycles in pastGlacier Lake Agassiz

Section 6

Question Answer
Tarn:Lake in Cirque
Kettles: Bowl shaped basin formed when blocks of stagnate ice melt, form ponds
Pluvial Lakes: Lakes formed during cooler, wetter climates (Great Salt Lake, Utah)
Playa Lake: Temporarily lake at low point in arid, basin, dry