In a groundbreaking study, researchers have finally solved the mystery surrounding the age of Earth’s largest sand dunes. According to BBC, these dunes also called ‘Star dunes’ or ‘pyramid dunes’ are named after their distinctive shapes and reach hundreds of metres in height. They are widespread in deserts including the sand seas of Africa, Arabia, China, and North America, as well as on Mars and Saturn’s moon Titan.

Prof Geoff Duller of the Department of Geography and Earth Sciences at Aberystwyth said, ”They are extraordinary things, one of the natural wonders of the world. From the ground, they look like pyramids but from the air, you see a peak and radiating off it in three or four directions these arms make them look like stars.”

Now, researchers have estimated the age of one such star dune called Lala Lallia in Morocco, for the first time. 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.

For the study, the research team from the UK travelled to the southeast of Morocco to examine the 100-meter-high and 700-meter-wide Lala Lallia. They discovered that the very base of the dune was 13,000 years old, but the upper part of the structure had only been formed in the last 1,000 years or so, The Guardian reported. The dune took 900 years to form, growing by 6,400 metric tonnes every year. After its initial formation, it stopped growing for about 8,000 years and then quickly expanded in the past several thousand years.

These findings, according to researchers, support the theory that the star dune’s formation was accompanied by a change in wind direction over the years.

Birkbeck University’s and fellow study co-author Charlie Bristow explained, ”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. They form extraordinary and awe-inspiring landscapes… From the ground they can be intimidating, mobile mountains of sand.”
 

A military helicopter delivers aid in the aftermath of a deadly earthquake in Talat N’Yaaqoub, in Morocco September 12, 2023.
| Photo Credit: Reuters

The epicentre of Morocco’s devastating earthquake on 8 September was in the High Atlas Mountains, about 71km south-west of Marrakesh. Moina Spooner, from The Conversation Africa, asked Jesús Galindo-Zaldivar, who has been carrying out research on the formation of the Atlas mountains and the geology of the area, about the factors which led to this situation.

Moroccan earthquake survivors huddled for a night in the open on the High Atlas Mountains on Saturday, a day after the country’s deadliest quake in more than six decades killed more than 2,000 people and laid waste to villages.

Neighbours were still searching for survivors buried on the slopes, where houses of mud brick, stone and rough wood were cracked open and mosque minarets toppled by the quake that struck late on Friday. The historic old city of Marrakech also suffered extensive damage.

The Interior Ministry said 2,012 people had been killed and 2,059 injured, including 1,404 in critical condition. The U.S. Geological Survey said the quake had a magnitude of 6.8 with an epicentre some 72 km (45 miles) southwest of Marrakech.

In the village of Amizmiz near the epicentre, rescue workers picked through rubble with their bare hands. Fallen masonry blocked narrow streets. Outside a hospital, around 10 bodies lay covered in blankets as grieving relatives stood nearby.

“When I felt the earth shaking beneath my feet and the house leaning, I rushed to get my kids out. But my neighbours couldn’t,” said Mohamed Azaw. “Unfortunately no one was found alive in that family. The father and son were found dead and they are still looking for the mother and the daughter.”

Rescuers stood atop the pancaked floors of one building in Amizmiz, bits of carpet and furniture protruding from the rubble. A long queue formed outside the only open shop as people sought supplies. Underlining the challenges facing rescuers, fallen boulders blocked a road from Amizmiz to a nearby village.

Nearly all the houses in the area of Asni, some 40 km south of Marrakech, were damaged, and villagers were preparing to spend the night outside. Food was in short supply as roofs had collapsed on kitchens, said villager Mohamed Ouhammo.

Montasir Itri, a resident of Asni, said the search was on for survivors.

“Our neighbours are under the rubble and people are working hard to rescue them using available means in the village,” he said.

The village of Tansghart in the Ansi area, on the side of a valley where the road from Marrakech rises up into the High Atlas, was the worst hit of any Reuters saw. Its once-pretty houses, clinging to a steep hillside, were cracked open by the shaking ground. Those still standing were missing chunks of wall or plaster. Two mosque minarets had fallen.

Abdellatif Ait Bella, a labourer, lay on the ground, barely able to move or speak, his head bandaged from wounds caused by falling debris.

“We have no house to take him to and have had no food since yesterday,” said his wife Saida Bodchich, fearing for the future of their family of six with their sole breadwinner so badly hurt. “We can rely on nobody but God.”

The village is already mourning ten deaths including two teenage girls, an inhabitant said.

Tremors were felt as far away as Huelva and Jaen in southern Spain. The World Health Organization said more than 300,000 people were affected in Marrakech and surrounding areas.

RUNNING FOR SHELTER

Street camera footage in Marrakech showed the moment the earth began to shake, as men suddenly looked around and jumped up, and others ran for shelter into an alleyway and then fled as dust and debris tumbled around them.

In the heart of the old city, a UNESCO World Heritage site, a mosque minaret had fallen in Jemaa al-Fna Square. Some houses in the tightly packed old city collapsed and people used their hands to remove debris while they waited for heavy equipment, said resident Id Waaziz Hassan.

Morocco declared three days of national mourning, during which the national flag will be flown at half staff throughout the country, the royal court said on Saturday.

The Moroccan armed forces will deploy rescue teams to provide affected areas with clean drinking water, food supplies, tents and blankets, it added.

Turkey, where powerful earthquakes in February killed more than 50,000 people, was among nations expressing solidarity and offering to provide support.

Algeria, which broke off ties with Morocco in 2021 after escalating tensions between the countries focused on the Western Sahara conflict, said it would open airspace for humanitarian and medical flights.

The quake was recorded at a depth of 18.5 km, typically more destructive than deeper quakes of the same magnitude. It was Morocco’s deadliest earthquake since 1960 when a quake was estimated to have killed at least 12,000 people, according to the U.S. Geological Survey.

Mohammad Kashani, associate professor of structural and earthquake engineering at the University of Southampton, compared scenes of the aftermath to images from Turkey in February: “The area is full of old and historical buildings, which are mainly masonry. The collapsed reinforced concrete structures that I saw … were either old or substandard.”

Marrakech is due to host the annual meetings of the International Monetary Fund and World Bank from Oct. 9.

An IMF spokesperson, asked about the planned meetings, said: “Our sole focus at this time is on the people of Morocco and the authorities who are dealing with this tragedy.”

(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)

Washington:

A strong 6.8-magnitude earthquake struck southwest of Marrakesh, Morocco late Friday, according to the US Geological Survey, causing substantial shaking.

The quake hit 44 miles (71 kilometers) southwest of Marrakesh at a depth of 18.5 kilometers at 11:11 pm (2211 GMT).

It sent debris flying into narrow alleyways and items tumbling off shelves, according to video posted on social media.

USGS’s PAGER system, which provides preliminary assessments on the impact of earthquakes, issued an orange alert for economic losses, estimating significant damage is likely, and a yellow alert for shaking-related fatalities, indicating some casualties are possible.

USGS said that “the population in this region lives in structures that are highly vulnerable to earthquake shaking.”

Morocco experiences frequent earthquakes in its northern region due to its position between the African and Eurasian plates.

In 2004, at least 628 people were killed and 926 injured when a quake hit Al Hoceima in northeastern Morocco.

The 1980, the 7.3-magnitude El Asnam earthquake in neighboring Algeria was one of the largest and most destructive earthquakes in recent history. It killed 2,500 people and left at least 300,000 homeless.

(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)