EV203 Lesson AL
landforms associated with mesa-and-scarp terrains
(tables and cliffs caused by different material that weathers at differing rates)plateaus, mesas, buttes, and pinnacles
Overview of Arid Regions
Climate type : B Major biome: deserts Soil type: Aridisols Soil forming factor: Climate
What is alluvium?
Deposits of alluvium are sediment from water deposits.
Barchan Dunes
Dunes shaped like crescents with the tips pointing downwind from where there is little sand and a flat surface. The crescent forms when the wind is stable and fixed.
star dunes
Dunes that are isolated hills of sand that exhibit a complex, star like form. Develop where wind patterns are changing.
How does fluvial erosion influences landscapes of arid lands?
Fluvial erosion (water) works super quickly and causes flash floods.
plateaus
Largest Area of land in a mesa scrapa landform.... raised area of land, such as a hill or mountain, with a flat top
ventifacts
Rocks faceted by wind sand blasting
How are sand dunes formed?
Sand dunes are hills built from sand that is carried and dropped off by wind.
Mesas
Tables or protected rock
regions in north America for basin-and-range
Vegas california and western mexico
types of sand dunes
barchan, parabolic, transverse, longitudinal, star
Exotic streams
begins in a humid region and moves to a dry region (Nile) (colorado river)
playas
bottom of the valley, super dry where no water remains in the valleys. Usually from dried up lake beds that were (saline) they melt away.
saltation
bouncing of sand and rocks and then chain reaction of sand hitting stuff
bajadas
combo of alluvial fans... hanging walls conecting basin and range
buttes
cuter and smaller mesa and scarps.
Aeolian erosion
deflation and abrasion (caused by wind)
how does weathering influence landform development
differing rates of weathering in rocks casues shapes and slopes of landforms.
transverse dunes
dunes in a series of long ridges that are perpendicular to the direction of the wind
ephemeral streams
flows only breifly after the rainfall. intense erosion and transportation and deposition
longitudinal dunes (Seif dunes)
form parallel to prevailing winds where sand supplies are moderate
mesa scarp regions in North america
grand canyon
ranges
groups of mountains
blow outs
hollows formed by removal of partciles by wind called blowout.
saline lakes
lakes that have salty water. Water that doesnt flow, it just evaporates and leaves its minerals and salt. turns into a playa when it dries out.
traction
most of the sand is broken up and thrown into saltation or suspension
suspension
paricles moved by wind above.
abrasion erosion
physical weathering from strong turbulant wind
alluvial fans
rain falls on high hills. carries down a bunch of stuff. Fan-shaped deposits of sediments dropped by streams flowing out of mountains
Describe flash flood hazards
rains rapidly on saturated soil or dry soils with poor absorption ability. the debris flow can be catasphropic
landforms associated with basin-and-range regions
ranges, alluvial fans, bajadas, and basins
pinnacles
smallest verticle formations of the mesa scarp landform
how is rock moves through aeolian transportation
suspension saltation and traction
basins
valleys in mountain ranges
deflation erosion
wind picks up particles and removes them from an area.
