The desert’s enormous star dunes are mysterious structures. These sand dunes are found in some of Earth’s largest modern deserts, but also on the planet Mars and Saturn’s largest moon, Titan. Star dunes are giant sand dunes that get their name from the arms of sand and rock that spread down from a central peak. When viewed from above, they can resemble stars.
Scientists have now pinpointed the age of one of Earth’s oldest star dunes for the first time. The Lala Lallia star dune in southeastern Morocco is estimated to have formed 13,000 years ago, according to a study published March 4 in the journal Scientific Reports.
[Related: The Sahara Desert used to be green and lush. Then humans showed up.]
Star dunes are found in sandy seas across Africa, Arabia, China, and North America. They are believed to be the tallest dunes on the planet, with a star dune in China’s Badain Jaran Desert climbing to 984 feet.
Despite being very common today, evidence of star dunes have almost never been found in Earth’s geological record. The geologic record is like a time capsule made up of rock and sediment layers that allows geologists to get a glimpse of what the Earth looked like thousands of years ago. The absence of star dunes in rocks has puzzled scientists, since past deserts are a common part of Earth’s geological history, but not the types of dunes. Only one ancient star dune has been uncovered preserved in sandstone. It dates back about 250 million years and was found in present-day Scotland.
“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,” Geoff Duller, a geologist and Earth Scientist at Aberystwyth University in Wales, said in a statement. “It’s only because of new technology that we can now start to uncover their secrets.”
This new study used ground…
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