1. WIND DEPOSITION
• Wind formed deposits are called Aeolian
deposits.
• The rock particles in the Aeolian deposits are
generally well rounded and are sorted
according to their size and weight.
• Wind deposits are mainly two types
1. Accumulations of sand , called “Sand dunes”
2. Deposits of silt, called “Loess”
2.
3. 1. SAND DUNES
• A dune is a hill of sand built either by wind.
• Dunes occur in different shapes and sizes.
• Most dunes have a gentle slope towards the wind-ward
side and a steep face towards the lee-side.
• The valley or trough between the dune is called
SLACK.
• A Dune field is an area covered by extensive sand
dunes.
7. 1.Crescent dune
• Crescent shaped dunes with a steep slip face on
the inward or concave side.
• Commonly known as BARCHAN
8. 2. Transverse dune
• A relatively straight elongate dune oriented perpendicular to the
wind direction.
• They are formed in areas with strong winds where more sand is
available
10. 4.Parabolic
dunes
• U shaped mounds of sand with convex noses trailed by elongated
arms.
• These are formed around blowouts where the erosion of
vegetated sand leads to a U shaped depression
11.
12. 2.Sand Seas or Erg
An erg is a broad, flat area of desert covered with wind swept sand
with little or no vegetative cover.
13. 3. LOESS
• Is a deposit of wind blown silt and clay particles,
typically in the 20-25 micrometer size range
• these deposits are typically nonstratified and
have a grayish yellow colour.
• It composed of many minerals including quartz,
feldspar, hornblende and calcite.
14. 4. SABKHA
• Originated from an Arabic word meaning SALT FLAT.
• Sabkhas are forming along coastlines and are
characterized by evaporite-carbonate deposits with some
siliclastics.
15.
16.
17. 8. Ripple mark
Wave like undulations developed on the rock
surface by wind blown sands.
