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35 Cards in this Set
- Front
- Back
GLACIER
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a large, long-lasting mass of ice formed on land
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ALPINE GLACIATION
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glaciers found in mountainous regions (formed in valleys)
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CONTINENTAL GLACIATION
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glaciers covering a large part of acontinent (>50 km2)
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FIRN
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compacted mass of granular snow, (has pore spaces between
grains) |
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With more compaction, firn changes to ________ (no pore spaces)
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glacial ice
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Glaciers can be divided into 2 zones
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ZONE OF ACCUMULATION
ZONE OF ABLATION |
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ZONE OF ACCUMULATION
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upper part of a glacier where snow cover remains all year (more snow falls than melts)
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ZONE OF ABLATION
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lower part of the glacier where ice is lost by melting, evaporation, and calving
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CALVING
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is the breaking off of large chunks of ice when a glacier reaches a body of water (blocks float away as icebergs)
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EQUILIBRIUM LINE
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is the boundary between the zone of accumulation and the zone of ablation (marks to lowest position were snow remains all year)
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BASAL SLIDING
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sliding of a glacier as a single body(moves over
bedrock) |
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PLASTIC FLOW
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- movement that occurs within a glacier(does not move at base)
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RIGID ZONE
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top portion of glacier that rides passively over the plastic zone
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CREVASSES
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open fissures or cracks formed by different rates of movement of ice
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ABRASION
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rocks at the bottom of a glacier scrap and grind away at the bedrock, abrasion
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ABRASION produces:
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striations and rock flour
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STRIATIONS
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grooves and scratches in bedrock
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ROCK FLOUR
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very fine particles (mud-sized) formed from the grinding of bedrock
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PLUCKING
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breaking loose of bedrock by melting and freezing of water
in cracks |
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LANDSCAPES PRODUCED BY ALPINE GLACIATION (valley glaciers)
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HANGING VALLEYS
CIRQUE TARN HORN ARETES |
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HANGING VALLEYS
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Thicker the glacier, the more vertical erosion it produces. so trunk (main) glacier erodes
much deeper than smaller tributary glaciers |
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CIRQUE
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steep-sided, half-bowl shaped depressions carved into amountain at the
head of a glacier |
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TARN
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lake found in a cirque
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HORN
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sharp peak that remains after cirques cut back into a mountain on several
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ARETES
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sharp ridges separating adjacent glacially carved valleys
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LANDSCAPES FORMED BY CONTINENTAL GLACIATION
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- do not form rugged topography like alpine glaciers
- form rounded topography - form grooved, striated bedrock and rounded elongated mountains |
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Sediment produced by glaciation is ____
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- ANGULAR, MULTI-SIZED, UNSORTED
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TILL
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unsorted, unlayered rock debris carried by glaciers
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MORAINE
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specific types of till deposits that occurs on a glacier or left behind by a
glacier |
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Types of moraines:
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Lateral moraine, Medial moraine, End moraine
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LATERAL MORAINE
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ridge like bodies of till along the sides of a valley
glacier |
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MEDIAL MORAINE
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ridge of till formed where two adjacent lateral moraines
join and are carried down the glacier |
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END MORAINE
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crescent-shaped bodies of till that form at the terminus of
a glacier |
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Glacial Age
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period of geologic time when world temperatures were cold
enough to produce extensive glaciation. |
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FIORD
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coastal inlet that is a drowned glacially carved valley
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