Scientists solve the mystery of the size of giant “stellar sand dunes” – BBC News Thailand

Image source, C Bristow


The stellar sand dunes of Lala Lalia in Morocco are 100 meters high.

We finally know the age of the world's largest and most complex sand dunes. This is the first time in history.

Star dunes or pyramid dunes are named after the unique shape of the sand and can reach hundreds of meters in height.

Sand dunes like this are found in Africa, Asia, and North America. Including on Mars, but experts have not clearly determined that. When were these sand dunes formed?

Even today, scientists have discovered that sand dunes called “Lala Lalia” are located in Morocco. It originated 13,000 years ago

Star sand dunes are formed by winds blowing from two directions.

Professor Geoff Dahler, from the University of Aberystwyth, who published the research alongside Professor Charles Bristow, from Birkbeck University, said that knowing the age of the dunes could help scientists understand wind and climate patterns in the past.

Lala Lalia is a name from the language of a local Berber tribe, meaning this sand dune is located in the Erg Chebbi desert in southeastern Morocco. It is 100 meters high and 700 meters wide.

The research results found that after the formation of the early sand dunes, the Lala Lala dunes stopped expanding for 8,000 years, and then rapidly expanded in size over the past few thousand years.

Scientists can usually determine the appearance of deserts on Earth from geological history. But Star Dune is never specified in what period it takes place. Even today

Professor Dahler explains that this may be because the sand dunes are so large. Even the experts did not notice that this unique sand dune.

But “discovering the age of these sand dunes will shock many people.” Because it shows how quickly giant sand dunes can form. It moves across the desert at a rate of about 50 centimeters per year.

Scientists use a technique called light emission dating (scintillation dating) to determine the age of star dunes by checking when was the last time a grain of sand was exposed to sunlight?

Image source, C Bristow

Scientists took sand samples from deep within the dunes. Come check it out in the lab. Using a dull red light. Similar to traditional compression

Professor Dahler explains that the mineral scales found in the sand are similar and are called “rechargeable batteries” because they store energy from natural radioactivity in the environment. Inside the sand crystal

The longer that portion of sand is buried underground, the more likely it is to be buried. This means that he will only be exposed to more radioactivity. This leads to a higher accumulation of energy in the sand grains.

Then when the sand seeds were examined in the laboratory. It will release energy in the form of light. This allowed scientists to calculate his age.

“In our dark laboratory, we saw the light that the sand gave off. The brighter the light, the brighter it is. This means that the sand grains are just getting older,” said Professor Dahler.

Other sand samples that scientists also examined include: The Star Sand Dune in Colorado, the highest sand dune in the United States. Its height from its base to its highest point is 225 metres.

Professor Dahler explains that climbing these sand dunes is a very difficult task. “Because once you take two steps up, you take one step down, but it's worth it. The pictures from the top of the dunes are beautiful.”

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