extreme dryness that may be hot or cold
desert
this kind of desert:
-low latitudes
-low elevations
-far from oceans
hot
this kind of desert:
-high latitudes
-high elevations
-near cold ocean currents
cold
these deserts are the Earth's largest. form due to patterns of atmospheric convection
subtropical deserts
this desert is when moist ocean winds are driven up and over mountains. windward air if forced to rise, expand, and cool, moisture condenses, rains fall, and creates a rain forest. leeward air, stripped of moisture sinks toward the surface, sinking air wa
rain shadow deserts
cool air over cold ocean water holds little moisture and this air absorbs moisture when it interacts with land. The Atacama Desert in Peru is the driest place on Earth and is one of these
Coastal deserts
Air loses moisture as it crosses continents. ex Gobi Desert in Mongolia
Interior deserts
when air circulation carries dry air to polar regions, it is so cold the air can't hold moisture
Polar deserts
the dark surface coating of iron and manganese oxides. forms very slowly from bacterial activity, dust, and water. native americans carved petroglyphs here
desert varnish
this in rock weather produces vibrant colors
iron oxides
dry stream channels
dry washes, arroyos, wadis
when grains move in contact with land surface, coarser sand sized particles
surface load
when sand skips and bounces by grain impact
saltation
when sediment is carried in the air, finer grained silt sized dust
suspended load
coarse coasts cannot be lifted and moved by wind so when the finer sediment is removed, this is formed
lag deposits
stones with wind faceted upper surfaces
ventifacts
concentrated wind erosion creates this
blowout
lowering the land surface via erosion
deflation
erosional debris accumulates as this. joint bounded blocks break off ledges and cliffs, debris tumbles down slope and accumulates at base
talus aprons
when alluvial fans coalesce along a mountain front
bajadas
when desert lake evaporates, leaving dry flat lake bed
playas
sand forms dunes inside deserts. vast areas of dunes are called
sand seas
Cliff retreat in a plateau of flat-lying rocks that are large, top may be several km
mesas
Cliff retreat in a plateau of flat-lying rocks, medium sized
buttes
Cliff retreat in a plateau of flat-lying rocks, end result, height exceeds top surface area
chimneys
steep, joint-controlled cliff; less steep dip slope.
cuesta
steeply dipping beds create a symmetric ridge
hogback
eroded remnant of almost complete cliff retreat
inselberg
mosaic like arrangement of surface stones
desert pavement
ramp-like bedrock surfaces that slope up toward a mountain front
pediments
gently sloping, gravelly alluvial fans
stony plains
windblown accumulations of sand
sand dunes
aridification of non desert areas because of overpopulation, overgrazing, diversion of water supplies
desertification