Geography 14
Arid lands: Major erosional agent is,__________. Most desert surfaces are,_______. Produced by,__________, weathering. Steep slopes that retreat,__________, and exposing,____, angle pediments.
Fluvial, rocks, mechanical, parallel, low-angle,
Reg= desert,___________. Formed by,__________, or sediment,___________.
Stony deserts, pavement, deflation,accumulation,
Which of the following is NOT TRUE about playas:
They develop in canyons of entrenched desert rivers where a local base level causes a shallow lake to accumulate
Which of the following is NOT true of loess deposits?
They were formed in playas in basins of internal drainage
Loess: _________, of deserts and,______/_________, sand deposits very,_______. Loess Plateau = glacial/periglacial=
downwind, glacial/periglacial, fertile, China(largest/thickest deposits) Midwest
Basins of interior drainage: no outlet to ocean Only permeable rivers are,________. Ephemeral streams: high,_________,(incision), and high,_________(large size of bed load= _________ for abrasion and incision)
exotic, capacity, competence, tools,
Which of the following is NOT one of the major causes of increases in desertification:
exposure of previously buried sand deposits by erosion
Desert Landscape of US West: Basin and Range: _______, tilt blocks, _______, fans, _______,_______(Hueco,Mesilla),______, salt pans. Mesa and Scarp: Plateau, mesa, butte, _______/______, badlands(_______Canyon), arches and,_______ bridges.
faulted,alluvial, bajada,bolson, playa, pinnacle/pillars,Bryce, natural
Aeolian Erosion and Deposition: Fluid,______, and _____,selective, Abrasion->________. Transport:(3) within 10 cm of ground
flow,size, yardangs, suspension,saltation, traction,
The energy of waves striking a headland that protrudes into the sea is,_________, than that which strikes the beaches adjacent to it because_________:
greater, refraction concentrates energy onto the headland
Haboobs were common during the Dust Bowl years as the High Plains dried out and blew away. Haboobs are:
intense dust storms, associated with thunderstorms or dry cold fronts, like a wall of dust, hundreds of feet high, approaching and darkening the sky,
Desert landscapes:(3)
-Erg -Reg -Hamada
Dune types:(4)
-barchans -transverse -longitudinal -star dunes
Eolian deposition:(3)
-sand seas -dunes -loess
Aeolian Erosion and Deposition: Dust storms: Strong winds >___mph, _____,soil,_____,soil,______,sediments.
20, bare,sandy,sandy,
The world's largest sand sea is in the,__________. The most common desert surface is covered by stones and is known as_______:
Arabian desert,...reg
Hamada=
Barren bedrock surface
Barchans: _________, with horns _________, limited supply of,______. Transverse: low consistent,_______. _____, of sand. Longitudinal:result of,___, prominent wind, _________. Star Dunes: winds from,_________, directions. __________, sand volume
Crescent, downwind, sand, winds, lots, 2, directions several, massive
Aeolian Erosion and Deposition: Long distance transport from:________/________, across,_________, to,__________, and,_________,and,_________. From,______, and other deserts in,____, across,__________, to US,______ coast. Impact: erodes soil,__________; deposits in the,______, feed,___________, stops,___________, from forming,
Sahara/Sahel, Atlantic,Caribbean, Florida, Texas, Gobi,Asia, Pacific, West, nutrients, oceans, phytoplankton, hurricanes,
Desertification:______(sub-Saharan Africa) White Sands: ________, dunes(largest deposit in the world,______ sq. miles) Interior drainage of,________, Basin, evaporates up to ___ inches/year some dunes move up to,___ ft/yr
Sahel, Gypsum, 275, Tularosa, 80, 30,
Erg= sand weathered in ________, climates and transported to desert plain; shaped by,________. Only __-__% of Sahara covered by sand Sandiest= Largest sand sea= Smaller examples=
Sand seas humid, wind, 10-20%, Arabian, Empty Quarter, White sands, Great Sand Dunes NP,CO
Deep, narrow gullies like those on the side-slopes of the Franklin Mountains are known as,_________. They are carved by,__________ streams. Major rivers that cross desert regions are known as exotic rivers. They are fed by,__________.
arroyos...ephemeral streams...headwaters in distant mountains with rain and/or snowmelt
A continuous depositional apron,known as a,________, may form when individual alluvial fans coalesce into one sloping surface. This feature contrasts with a __________, which is an erosional surface along a mountain front where bedrock is covered by a thin veneer of alluvium.
bajada,...pediment
Waves: waves of,__________, in open ocean in,________, orbits to depth of,__ wavelength Waves approach shore-> waves affected by,____, with sea-floor.-> tilt,________, into wave of,________, and eventually breaks. Swash and Backwash: Erosion by,_______, and,________. Wave,__________ onto,__________(concentrates energy of erosion); divergence into bays
oscillation, circular,1/2, drag, forward, translation, impact, abrasion, refraction, headlands
Aeolian Erosion and Deposition: Haboobs: _________, from thunderstorm in ____________, US, dry,______,front __ recently in Texas
outflow, Southwest, cold, 2,
Fluvial processes: Differential weathering and erosion- strong influence of,_______,type and,__________. Gentler,lower debris,_______. Caprocks ex= Canyons, Mesas, Buttes, Badlands ex= Ephemeral stream channels: ___________ (aka gullies, washes, coulees) Residual surfaces and features: (3)
rock,structure, slopes, Monument Valley Bryce Canyon UT arroyos inselbergs,pediments,bornhardts(old uplands)
Many desert landscapes evolve with:
steep slopes on resistant rocks that retreat parallel and maintain their steepness expansion of gently sloping rock-cut pediments as mountains are worn back Arroyos cut by occasional ephemeral streams
Arid Regions: __________ High Pressure cells,___-___ N, _____-shadow deserts in lee of mountain ranges, ________, interiors far from ocean,
subtropical, 15-35, rain, continental,
Open-ocean waves become waves of,_______, when the water circulation is affected by drag with the sea-floor. Their wavelength,_______, and their wave height,________. Eventually the waves break.
translation...decreases...increases