Aeolian Environment Flashcards
a. Less than 250mm/yr precipitation
b. between 250 and 500mm/yr
a. Desert (Arid)
b. Steppe (Semi-Arid)
(a) -Regions near 30° N & S latitude air sinks
(subtropical highs)
-Produce clear skies, sunshine, and ongoing
drought
(b) Give one example
Low Lattitude Desert
Simpson Desert
(a) -Located in the deep interiors of continents
- Precipitation only 10-20 cm/yr
(b) Give one example
Mid Lattitude Desert
Gobi Desert
are formed because tall mountain ranges prevent moisture-rich clouds from reaching areas on the lee, or protected side, of the range. As air rises over the mountain, water is precipitated and the air loses its moisture content.
Rainshadow Desert
- Mean summer temperatures of -1.5 to 2° C
- Mean winter temperatures of -32 to -23° C
(b) Give one example
Polar Desert
Antarctic Desert
is an area where sand has accumulated as a result of
aeolian processes.
Erg
is blowing out and scattering of rock particles by
wind.
Deflation
are sandy depressions in a sand dune ecosystem
(psammosere) caused by the removal of sediments by wind
Blowouts
is the mechanical scraping of a rock surface, by
friction between rocks and moving particles
Abrasion
Long exposure of rock surface in the oxidizing conditions of a desert also results of a dark, surface patina of iron and manganese oxides
Desert Varnish
impact of saltating grains to have a frosted patina, like the frosting of glass windows
Grain Surface Frosting
the selective removal of finer grains from the sediment in a flow, but is more effective in the lower density and viscosity medium of air
Winnowing Effect
consisting of gravel-sized particles that are too large to be transported by the wind
Lag Deposits
are dust that accumulate far from their source
Loess
a hill or ridge of wind-deposited sand. Ranges from
3m to 600m in wavelength and are between 10cm and 100m high.
Dunes
lunate structures with arcuate slips faces forming cross-bedding
Barchan Dunes
straight-crested forms aligned perpendicular to the prevailing wind direction
Transverse Dunes
a variety of dune intermediate between barchan and transverse dunes;these dunes form scalloped rows of sand perpendicular to the wind
Barchanoid Dunes
characterized by cross-bedding reflecting avalanching down on both sides of the dune and oriented in different directions
Longitudinal Dunes
– slip faces in many orientations and hence crossbedding directions are variable
Star Dunes
initially originate as blowouts and the dune forms as the head of the dune at the downwind edge of
the blowout
Parabolic Dunes
wind eroded (sand blasted) surfaces. With changing direction of dominant winds, different facets merge along sharp ridges to transform rounded stones to angular \_\_\_\_\_\_\_\_\_
Ventifacts
are larger hill-sized features sculpted by the
wind. It is composed of cohesive silts and clays, sandstone, or limestone
Yardang
An isolated mountain remnant characteristic of
the late stage of erosion in a mountainous region
Inselberg
a broad, flat-topped area elevated above the surrounding land and bounded, at least in part, by cliffs.
Plateau
a broad, flat-topped hill bounded by cliffs and capped with a resistant rock layer
Mesa
a narrow hill of resistant rock with a flat top and very steep sides
Butte
is determined by the amount of water that is charging the water-bearing strata
Water Table
– sand dunes built up by aeolian action that from
adjacent to beaches in any climatic setting
Beach Dunes
Wind blowing over the outwash plain can pick up sand
and redeposit it locally, such as the side of a valley.
Periglacial Deposit
