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Desert Star Dunes

Facts for Prelims (FFP)

 

Source: TH

 Context: Scientists have revealed the secrets of Earth’s magnificent desert star dunes, showcasing the internal structure and formation process of these geological wonders.

 

The study focused on the Lala Lallia star dune in eastern Morocco, uncovering its intricate layers and estimating it took about 900 years to form, accumulating sand at a rate of approximately 6,400 metric tons annually. These star dunes, accounting for under 10% of Earth’s desert dunes, are the tallest and most impressive, resembling pyramids with arms extending from a central peak.

 

Desert star dunes have a distinctive internal structure and formation process:

  1. Internal Structure: Revealed through ground-penetrating radar, it shows layers formed over time through accumulating sand. Some parts resemble other types of dunes.
  2. Formation Process: Formed by opposing winds with changing directions, resulting in a unique star shape. Winds blowing from different directions lead to net sand accumulation, creating giant dunes.

 

What are Dunes and its different types?

Dunes are mounds, ridges, or hills of sand formed by the wind in deserts, coastal areas, or other sandy environments. They come in various shapes and sizes. The different types of dunes include:

  1. Barchan Dunes: Crescent-shaped dunes with the tips pointing downwind, commonly found in areas with limited sand.
  2. Linear Dunes: Long and straight dunes that form parallel to the prevailing wind direction.
  3. Star Dunes: Pyramid-shaped dunes with arms radiating from a central peak, forming in areas with complex wind regimes.
  4. Transverse Dunes: Long ridges of sand perpendicular to the wind direction, often found in extensive sand seas or deserts.
  5. Parabolic Dunes: Similar to barchan dunes but with the tips pointing upwind, typically forming in areas with abundant sand and vegetation.
  6. Dome Dunes: Rounded mounds of sand with no specific orientation to the wind direction, often found in coastal regions or sandy plains.