Scientist unveiled (present) the 1^st in depth study of star dune, revealing the internal structure of these geological features and the process of its formation.

1. The study focused upon a star dune in eastern Morocco called Lala Lallia, meaning ‘highest sacred point’ in the local Berber language, situated within the Sahara Desert.
2. The scientists used a technique called luminescence dating to work out the age of the star dune. The method calculates when the grains of sand were last exposed to daylight.
3. It took about 900 years, accumulating roughly 6,400 metric tons annually as wind blows sand through the desert.

 About Star Dunes 

1. Star dunes, also known as pyramid dunes, have unique shapes and can reach hundreds of meters in height.
2. They are found in various continents and have been observed on Mars and Saturn's moon Titan.
3. Star dunes make up around 10% of Earth's desert dunes and are the tallest among different types like crescent-shaped barchan dunes and straight linear dunes.

 Sand Dunes Formation 

1. Sand dunes form in areas with complex wind patterns, where winds blow from different directions and accumulate sand, creating large piles that shape into giant dunes.
2. Barchans: These are crescent-shaped dunes created by wind predominantly from one direction.

• They are widespread in sandy deserts globally.
• Barchans are curved towards the wind, with the tips pointing downwind, indicating sand movement.
• They have a gentle slope facing the wind and a steeper slope, the slip face, facing away.

3. Parabolic Dunes: Similar to crescent-shaped dunes but with the slip face on the inward side.

• Also known as blowouts as wind blows out the dune center, leaving a rim.

4. Transverse Dunes: When Barchan dunes align perpendicular to the wind, they form transverse dunes.

• These dunes advance forward as sand slides down their slope, one step at a time.

 Geographical Distribution 

1. Earth's largest star dunes are located in the Badain Jaran desert in western China.
2. Other significant locations include Namib Sand Sea in Namibia, sand seas in Algeria like the Grand Erg Oriental and Grand Erg Occidental, and Rub' al Khali in Saudi Arabia.
3. In North America, Great Sand Dunes National Park in Colorado features a series of star dunes.

 Key Facts for Prelims 

1. India’s First Sand Dune Park to Come Up in Goa.
2. The World Bank has sanctioned Rs 3 crores to the Goa state government for the project.

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