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Theri Desert

JUN 18

Preliminary   > Geography   >   Places in news   >   Places in news

About Theri Desert:

  • Most of us may not know the small desert situated in the state of Tamil Nadu. It consists of red sand dunes and is confined to the Thoothukudi district.
  • The red dunes are called theri in Tamil.
  • They consist of sediments dating back to the Quaternary Period and are made of marine deposits.
  • They have very low water and nutrient retention capacity.
  • The dunes are susceptible to aerodynamic lift.
  • This is the push that lets something move up. It is the force that is the opposite of weight.

Mineral composition of Theris

  • The analysis of the red sand dunes reveal the presence of heavy and light minerals.
  • These include ilmenite, magnetit, zircon, hematite, quartz etc.
  • The iron-rich heavy minerals like ilmenite, magnetite and rutile present in the soil had undergone leaching by surface water.
  • They were then oxidised because of the favourable semi-arid climatic conditions.

How did they form?

  • Theris appear as gentle, undulating terrain.
  • The lithology of the area shows that the area might have been a paleo (ancient) coast in the past.
  • The presence of limestone in many places indicates marine transgression.
  • The present-day theris might have been formed by the confinement of beach sand locally, after regression of the sea.
  • When high velocity winds from the Western Ghats blew east, they induced migration of sand grains and accumulation of dunes.

PRACTICE QUESTION:

Theri Desert is located in which of the following states in India?

(a) Rajasthan

(b) Ladakh

(c) Tamil Nadu

(d) Gujarat

Answer


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