Star dunes are among the most impressive and complex sand formations on Earth and other planets. They can reach hundreds of meters in height and have arms that radiate from a central peak. But how old are these giant dunes and how do they move across the desert? Scientists have recently solved some of these mysteries using new technologies and techniques.
What are star dunes?
Star dunes are a type of sand dune that forms when winds blow from multiple directions, creating a star-like shape when viewed from above. They are found in some of the world’s largest deserts, such as the Sahara, the Namib, the Badain Jaran and the Rub’ al Khali. They are also present on Mars and Titan, indicating that similar wind patterns exist on these planetary bodies.
Star dunes are not static structures, but dynamic ones that change over time. They grow by accumulating sand from the surrounding area, and they move by sliding or rolling down their slopes. The rate of growth and movement depends on the wind strength, frequency and direction, as well as the availability of sand.
How old are star dunes?
One of the challenges of studying star dunes is estimating their age. Until recently, scientists had no reliable way of dating these massive sand piles. However, a team of researchers from Aberystwyth University and Birkbeck University have developed a method that combines ground-penetrating radar and luminescence dating to determine when the sand grains were last exposed to sunlight.
Using this method, they analyzed a star dune named Lala Lallia in Morocco, which is one of the largest and most complex star dunes in the world. They found that Lala Lallia formed about 13,000 years ago, during a period of increased aridity and wind variability in North Africa. They also discovered that the dune stopped growing for about 8,000 years, and then resumed its expansion in the past several thousand years.
Why are star dunes important?
Star dunes are not only fascinating natural wonders, but also valuable sources of information about the past and present climate of Earth and other planets. By dating star dunes, scientists can reconstruct the history of wind patterns and aridity in different regions of the world. By comparing star dunes on Earth with those on Mars and Titan, scientists can learn more about the similarities and differences between these planetary environments.
Star dunes also have cultural and ecological significance. They are often considered sacred places by local people, who use them for rituals and ceremonies. They also provide habitats for various plants and animals that have adapted to the harsh desert conditions.
Star dunes are magnificent desert features that reveal the secrets of Earth’s largest sand seas.
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