PRABHU JAGATBANDHU COLLEGEDEPARTMENT : GEOGRAPHY

CLASS : B.A/B.SC PART 1(HONS)

GUEST FACULTY : PRIYANKA SANPUI

IN THE HONOUR OF NAAC VISIT_2014

A MICROSOFT POWER POINT PRESENTATION CLASS

TOPIC : IMPACT OF AEOLIAN PROCESSES ON LANDFORM DEVELOPMENT

Aeolian Processes & Landforms

The word ‘Aeolian’ derives from Aeolus the Greek God of winds. Wind erosion processes consist of abrasion, the scouring of exposed surfaces by the sand blasting action of wind blown materials, and deflection and the removal sand sized & smaller particles by the wind.Wind Deflaction : Intense erosion lowers elevation of a region. A velocity of 50 km/hr is required to produce significant movement of sand by wind.

Ventifacts : Multiple faceted pebbles ---VENTIFACTS are formed from dolerite rocks in Taylor valley,Anterctica. This group of rocks are likely started as single rock that over time has broken apart. The wind has eroded the surfaces that appear gray while, the reddish part of the rock is simply the weathered surface of rock patina. The inset picture show another example of rock breaking apart in place and being eroded by the wind.

Barchans Dunes :These are crescent shaped dunes lying at right angles to the prevailing wind and having a steep, concave leeward side with the crescent tips pointing downwind. Barchans dunes generally form on flat & hard surfaces where the sand supply is limited.

Parabolic Dunes :These are U-shaped mounds of sand with convex noses trailed by elongated arms.

Transverse Dunes :Transverse dunes have same characteristics as the barchans dunes. But their leeward side slope is more steeper. They generally form in areas of sparse vegetation and abundant sand. Most beach dunes are transverse dunes.

Longitudinal Dunes :

Large elongated dunes lying parallel to the prevailing wind direction. They usually have symmetrical cross sections, form in areas where sand is abundant and the wind is constant and strong. They are usually tens of meters high and up to 100 km long.

Star shaped Dunes :Radically symmetrical, STAR DUNES are pyramidal sand mounds with slip faces on three or more arms that radiate from the high centre of the mound. They tend to accumulate in areas with multidirectional wind regimes. Star Dunes grow upward rather than laterally.

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