Monday, November 28, 2011

Wind Processes (eolian)

Alluvial Fan: A fan-shaped deposit of sediment formed when a stream's slope is abruptly reduced.
Playa: The flat central area of an undrained desert basin.
Horst: An elongate, uplifted block of crust bounded by faults.
Graben: A valley formed by the downward displacement of a fault-bounded block.
Mesa: An elevated area of land with a flat top and sides that are usually steep cliffs.
Butte: Similar to a mesa, but with steeper sides.
Pinnacle
Star Dune: An isolated hill of sand that exhibits a complex star-like form and develops where wind directions are variable
Barchan Dune: A solitary sand dune shaped like a crecent with its tips pointing downwind.
Transverse Dune: A series of long ridges oriented at right angles to the prevailing wind; these dunes form where vegetation is sparse and sand is very plentiful.

Depositional

Terminal Moraine: The end moraine marking the farthest advance of a glacier.
Lateral Moraine: A ridge of till along the sides of a valley glacier composed primarily of debris that fell to the glacier from the valley walls.
Medial Moraine: A ridge of till formed when lateral moraines from two coalescing alpine glaciers join.
Drumlin: A streamlined symmetrical hill composed of glacial till. The steep side of the hill faces the direction from which the ice advanced.
Kettle: Depressions created when blocks of ice become lodged in glacial deposits and subsequently melt.
Esker: Sinuous ridge composed largely of sand and gravel deposited by a stream flowing in a tunnel beneath a glacier near its terminus.
Proglacial lake: A lake formed from glacier runoff, filling a depression caused by the glacier.





Erosional



Horn: A pyramid-like peak formed by glacial action in three or more cirques surrounding a mountain summit.
Cirque: An amphitheater-shaped basin at the head of a glaciated valley produced by frost wedging and plucking

Hanging Valley: A tributary valley that enters a glacial trough at a considerable geight above the floor of the trough.
Glacial Trough: A mountain valley that has been widened, deepened, and straightened by a glacier.
Arete: A narrow, knifelike ridge separating two adjacent glaciated valleys.
Fiord: A steep-sided inlet of the sea formed hen a glacial trough was partially submerged.