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Scientists Reveal Secrets of Desert Star Dunes

A view of the Lala Lallia star dune of the Sahara Desert, in Erg Chebbi, Morocco, as seen in an undated handout image from 2008 and obtained by Reuters on March 1, 2024. Charlie Bristow/Handout via REUTERS
A view of the Lala Lallia star dune of the Sahara Desert, in Erg Chebbi, Morocco, as seen in an undated handout image from 2008 and obtained by Reuters on March 1, 2024. Charlie Bristow/Handout via REUTERS
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Scientists Reveal Secrets of Desert Star Dunes

A view of the Lala Lallia star dune of the Sahara Desert, in Erg Chebbi, Morocco, as seen in an undated handout image from 2008 and obtained by Reuters on March 1, 2024. Charlie Bristow/Handout via REUTERS
A view of the Lala Lallia star dune of the Sahara Desert, in Erg Chebbi, Morocco, as seen in an undated handout image from 2008 and obtained by Reuters on March 1, 2024. Charlie Bristow/Handout via REUTERS

They are among the wonders of our deserts: star dunes, the vaguely pyramid-shaped sand formations up to about 1,000 feet (300 meters) tall with arms stretching out from a central peak to give them a star-like appearance when viewed from above.
Scientists on Monday unveiled the first in-depth study of a star dune, revealing the internal structure of these geological features and showing how long it took for one of them to form - more quickly than expected but still a process unfolding over many centuries.
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 in a small sand sea called Erg Chebbi about 3 miles (5 km) from the town of Merzouga, close to the border with Algeria.
Lala Lallia rises about 330 feet (100 meters) above the surrounding dunes and is approximately 2,300 feet (700 meters) wide, containing about 5-1/2 million metric tons of sand.
According to Reuters, he researchers used ground-penetrating radar to peer inside the dune and employed luminescence dating to determine how long Lala Lallia has taken to form, a method based on the amount of energy trapped inside the grains of sand. The answer: about 900 years, accumulating roughly 6,400 metric tons annually as wind relentlessly blows sand through the desert.
Star dunes make up just under 10% of the dunes in Earth's deserts and are the tallest ones, surpassing other types such as crescent-shaped barchan dunes and straight and lengthy linear dunes. They also have been spotted on Mars and on Saturn's large moon Titan.
"I first encountered star dunes in Namibia 20 years ago, and was instantly amazed at the size of them. I have a vivid memory of the long climb to the top, struggling up very loose sand in the heat of the day," said geographer Geoff Duller of Aberystwyth University in Wales, co-author of the study published in the journal Scientific Reports.
"I find desert dunes very beautiful," Duller added. "The sight of the sinuous curves, and the way that the light and shadow changes with the sun mean that they always look different, whether that is in the cool of the morning, the midday sun or near sunset. The different colors of sand in different deserts are also very striking, with yellow, white, red and even black dunes in different parts of the world."
The ground-penetrating radar revealed the layers within the Lala Lallia dune, showing how it was constructed over time through accumulating sand and how parts of its internal structure resembled other types of dunes.
"Star dunes are formed in areas with complex wind regimes, which means winds blowing from different directions, and net sand accumulation, points within the desert where big piles of sand can be blown around to form giant dunes," said Birkbeck University of London sedimentologist and study co-author Charlie Bristow.
The researchers also determined that Lala Lallia is moving westerly at a speed of about 1.6 feet (0.5 meters) annually.
While many star dunes are known today, only a single ancient one has been found preserved as sandstone in the geological record, dating to about 250 million years ago, in Scotland. By revealing their internal structure, the researchers said their findings provide a guide for geologists to identify more sandstone remnants of ancient star dunes.
Earth's largest star dunes are found in the Badain Jaran desert in western China. Star dunes also are found in places including the Namib Sand Sea in Namibia, large sand seas in Algeria such as the Grand Erg Oriental and Grand Erg Occidental, and Rub' al Khali in Saudi Arabia. In North America, Great Sand Dunes National Park in Colorado contains a series of them.
"They form extraordinary and awe-inspiring landscapes," Bristow said. "From the ground they can be intimidating, mobile mountains of sand."

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NEOM Nature Reserve Reintroduces Six Animal Species

NEOM is working to rebuild self-sustaining ecosystems through habitat rehabilitation, species recovery, and cutting-edge ecological monitoring - SPA
NEOM is working to rebuild self-sustaining ecosystems through habitat rehabilitation, species recovery, and cutting-edge ecological monitoring - SPA
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NEOM Nature Reserve Reintroduces Six Animal Species

NEOM is working to rebuild self-sustaining ecosystems through habitat rehabilitation, species recovery, and cutting-edge ecological monitoring - SPA
NEOM is working to rebuild self-sustaining ecosystems through habitat rehabilitation, species recovery, and cutting-edge ecological monitoring - SPA

As part of its bold rewilding strategy, NEOM has reintroduced more than 1,100 animals across six species to its expansive Nature Reserve—an important milestone in its broader mission to restore the region’s natural balance. With 95% of the region’s land preserved for nature, NEOM is working to rebuild self-sustaining ecosystems through habitat rehabilitation, species recovery, and cutting-edge ecological monitoring.

According to NEOM, when the Arabian Oryx was first reintroduced into the Nature Reserve in December 2022, it marked a milestone occasion, signifying the first time the animal had walked the sands of north-western Saudi Arabia for nearly 100 years, SPA reported.

In the early 1970s, the Oryx was extinct in the wild due to hunting and poaching, but conservation efforts across the region have seen its numbers swell in recent years, with more than 208 now calling NEOM home. Perfectly adapted to the region’s desert conditions, its white coat reflects the sun, while its complex nasal system cools the air it breathes and conserves water by recycling moisture as it exhales.

Another member of the Bovidae family, Arabian Sand Gazelles are petite, graceful animals that typically reside in sand dunes and coastal flats across the Arabian Peninsula. Gazelles are swift creatures, clocking speeds of up to 100 kilometers per hour in short bursts.

They are herbivores, and while NEOM’s regreening initiative continues to develop – with 4.7 million trees, shrubs, and grasses planted to date – the 530 Arabian Sand Gazelles currently residing in the reserve benefit from the natural vegetation that has returned to the area, following the removal of heavy livestock grazing. NEOM is also home to 223 Arabian Gazelles, which are typically darker in color and harder to find, preferring to reside in foothills and rugged mountain terrain.

Desert-dwelling wild goats can be found in NEOM’s rocky, mountainous terrain, and are typically recognized by their impressive arched horns. Males have backward-arched horns that can reach up to one meter in length, while females have much shorter horns and are lighter in color.

They are incredible climbers and have hooves with rubbery soles to act as suction cups on hard surfaces, aiding them in navigating steep cliffs to avoid predators, including wolves. NEOM has successfully reintroduced 53 Nubian Ibex to the reserve, adding to the population of several wild Ibex who have naturally returned to the area and are often caught on camera as part of NEOM’s monitoring program.

The red-necked ostrich, the largest and fastest living bird on earth, can stand up to 2.7 meters tall and weigh more than 150 kilograms. Their eggs are the largest of any living animal, measuring up to 15 centimeters long and up to 1.4 kilograms in weight. The bird gets its namesake from the fact that males have a reddish hue on their neck, especially in breeding season, when they perform an elaborate courtship display to attract females.

Currently, 27 chicks have been raised in NEOM Nature Reserve, which are well adapted to the region’s climate and feed on seeds, grass, leaves, and occasionally small insects or animals. Their strong legs allow them to run up to 70 kilometers per hour and, despite their size, red-necked ostriches are flightless.

Furthermore, the Lanner Falcon, last spotted in the wild in Saudi Arabia more than four decades ago, was reintroduced to NEOM Nature Reserve earlier this year in a momentous occasion. Known for its speed and agility, the Lanner Falcon can dive at speeds of more than 320 kilometers per hour. It has a striking appearance, with dark markings on its chest and belly, and a distinctive black moustache mark across its white face.

The release of Lanner Falcons into Bajdah at NEOM Nature Reserve forms part of a rewilding partnership between NEOM and the Saudi Falcon Club (SFC), which aims to reintroduce native falcon species within the Kingdom.