Earth Science

7.2 vocab * Alluvial fan- a fan shaped deposit of sediment formed when a streams slope is abruptly reduced * Playa lake- a flat area on the floor of an undrained desert basin (playa) that fills and becomes a lake after heavy rain 7.2 outline * Weathering in Deserts: Although chemical weathering occurs in deserts, mechanical weathering is far more dominant in shaping desert landscapes. * Water in Deserts: In desert, water collects in streams and rivers that can deposit alluvial fans, forms playa lakes, and even carve steep-walled valleys, or canyons, through the desert.
-Desert streams
-Alluvial Fans
-Playa Lakes and Playas
7.3 vocab * Deflation- the lifting and removal of loose material by wind * Desert Pavement- a layer of coarse pebbles and gravel created when wind removed the finer material * Loess-deposits of windblown silt, lacking visible layers, generally light yellow, and capable of maintaining a nearly vertical cliff * Dune- a hill or ridge of wind deposited sand
7.3 outline * Wind Erosion: wind erodes land surfaces in two ways: deflation and abrasion. * Wind Deposits: The wind can create landforms when it deposits its sediments, especially in deserts and along coasts. Both layers of loess and sand dunes are landscape features deposited by wind. -Loess
-Sand Dunes: Wind can deposit sand in mounds or ridges called dunes when it encounters an obstruction. * Types of Sand dunes: The shape of a sand dune depends on the wind direction and speed, how much sand is available , and the amount of vegetation.
-Barchan Dunes
-Transverse Dunes
-Barchnoid Dunes
-Longitudinal Dunes
-Parabolic Dunes
-Star