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25 Cards in this Set
- Front
- Back
Glacier formations |
100s to 1000s years to form
accumulation, compaction and recrystallization of snow
important record of time |
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Types of Glaciers (2 types to know for exam) |
Continental/Ice sheets (only Greenland and Antarctica)
Alpine or Valley Glaciers (Alps, Alaska, Northern Rockies, Southern Andes, Himalayas) |
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Erosion and Landforms |
1. Plucking and Abrasion
2. Glacial Trough - U shaped valley
3. Glacial Striations |
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Plucking |
Occurs when melt water penetrates the cracks and joints along the rock floor of the glacier and freezes |
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Abrasion |
As the ice and its load of rock fragments slide over bedrock, they function like sandpaper to smooth and polish the surface below. |
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Glacial Trough |
The result during glaciation, narrow valleys undergo a transformation as the glacier widens and deepens them creating a U-shaped glacial trough |
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Glacial Striations |
scratches and grooves made when ice contains large rock fragments |
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Glacial Deposits |
Glacial Drift - sediments of glacial origin no mater how where or what form they were deposited (Till or Stratified Drift)
Moraines - Layers or ridges of till |
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Glacial Drift - two distinct types |
Till and Stratified Drift |
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Till |
Materials deposited directly by the glacier. Till is deposited as glacial ice melts and drops its load of rock debris |
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Stratified Drift |
Sediments laid down by glacial meltwater. It is sorted according to the size and weight of the fragments. |
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Effects of Glaciation |
1. Lithospheric Subsidence - Greenland
2. Lowering of Sea Level
3. Pluvial Lakes and Drainage Basins
4. Climate |
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Causes of Glaciation |
1. Plate Tectonics
2. Variations of Earth's orbit |
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Three types of Variations to Earth's orbit |
1. Eccentricity- elliptical orbit
2. Obliquity- 22.5 - 24.5 degrees
3. Precession - wobble of axis rotation |
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How much of Earth's surface is desert? |
30% |
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What are some misconceptions of deserts? |
1. Deserts are lifeless
2. Deserts are always hot (snow in Sonoran desert and Antarctica is a desert)
3. Deserts are vast expanses of sand
4. Desert erosion is caused by wind ~ it's caused mostly by water. |
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How do climatologists define "dry climate" |
A climate in which yearly precipitation is less than the potential loss of water by evaporation. |
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Ephemeral Streams |
Streams in response to specific episodes of rainfall. May only flow for a few days or hours |
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Interior Drainage |
A discontinuous pattern of ephemeral streams that do not flow out of the desert to the ocean. |
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Alluvial Fans |
A cone of debris at the mouth of a canyon |
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Bajada |
Over time Alluvial fans enlarge and connect with fans from adjacent canyons to produce an apron of sediment along the mountain foot. |
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Playa Lakes |
Streams may flow across the alluvial fans to the center of the basin converting the basin floor into a shallow lake lasting only a few days or weeks before evaporation and infiltration remove the water. |
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Desert pavement and deflation |
Over time, deflation lowers the surface and coarse particles become concentrated |
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Saltation |
Sediment moving appears to jump or skip along |
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Abraison |
Windblown sand cuts and polishes exposed rock surfaces. |