Star dune: Scientists solve mystery behind Earth's largest desert sands - BBC News

Scientists collected radioactive sand grains in the dark to understand when they formed.

13 hours agoShareclose panelShare pageCopy linkAbout sharingImage source, C BristowImage caption, The Lala Lallia star dune in Morocco is 100m highBy Georgina RannardScience reporter The age of one of Earth's largest and most complex types of sand dune has been calculated for the first time.

Star dunes - or pyramid dunes - are named after their distinctive shapes and reach hundreds of metres in height.

They are found in Africa, Asia and North America, as well as on Mars - but experts had never before been able to put a date on when they were formed.

Now scientists have discovered that a dune called Lala Lallia in Morocco formed 13,000 years ago.

Star dunes are created by opposing winds that change direction. Understanding their age helps scientists understand those winds and unpick the climate of that era, says Prof Geoff Duller at the University of Aberystwyth, who published the research with Prof Charles Bristow at Birkbeck University.

https://www.bbc.co.uk/news/science-environment-68450147

---