A new study from Aberystwyth University, Birkbeck, and UCL academics is the first to date how long it took a star dune to form and examine its internal structure.

Lala Lallia Star Dune in Erg Chebbi, Morocco. Credit: Prof. C Bristow
Lala Lallia Star Dune in Erg Chebbi, Morocco; Photo: Prof. C Bristow

Star dunes are large sand dunes that get their name due to the arms that spread from a central peak. Resembling stars when viewed from above, these sand pyramids are widespread in deserts in places like Africa, Arabia, China, and North America.

The new research has revealed that the oldest parts at the base of the dune are 13,000 years old. Additionally, despite scientists believing that larger dunes were far older, the research showed that the dune has reached its approximately 330-foot height and 2,300-foot width due to rapid growth over the past thousand years.

Believed to be the tallest dunes on Earth, star dunes can also be found elsewhere in our solar system including Mars and on Saturn’s moon Titan.

 

Though star dunes are fairly common in the modern day, they have rarely been found in geological records. Their absence in records has puzzled scientists as past deserts are a common part of Earth’s history, preserved in underground rocks.

“This research is really the case of the missing sand dune—it had been a mystery why we could not see them in the geological record. It’s only because of new technology that we can now start to uncover their secrets. These findings will probably surprise a lot of people as we can see how quickly this enormous dune formed, and that it is moving across the desert at about 50 cm a year. These fantastic star dunes are one of the natural wonders of the world.” stated Professor Geoff Duller, from the Department of Geography and Earth Sciences at Aberystwyth University.

Satellite image of Lala Lallia star dune from Google Earth 2023 Credit: Scientific Reports (2024)
Satellite image of Lala Lallia star dune from Google Earth 2023; Photo: Scientific Reports (2024)

The new findings suggest the star dune formed at approximately the same time as the Younger Dryas event, an abrupt cooling period in Earth’s history, and that it stopped growing for 8,000 years. Pottery found at the site suggests that wetter conditions may have stabilized the dune before the onset of a drought.

The team used ground-penetrating radar to look inside the star dunes and gain insights about how they formed. The study also used luminescence dating techniques developed at Aberystwyth University to discover the last time minerals in the sand were exposed to sunlight to determine their age. 

“It’s quite a privilege to think that the luminescence dating techniques developed here in Aberystwyth are unlocking some of the secrets of the most challenging climates in the world. They are giving us an insight into geology that could have wider implications including geological deposits that are used for water resources and storing carbon,” stated Professor Duller of Aberystwyth University.