They did this by cutting pits into the dunes and hammering in an old piece of drainpipe to gather the samples. One catch is that they have to collect the grains of sand without exposing them to light. We can measure that and the brightness tells us the last time the sand grain saw daylight.” When we bring it back to the laboratory, we can get it to release that energy. “It can store energy that it gets from naturally occurring radioactivity.

The grains of quartz have a property like a mini rechargeable battery. Luminescence dating techniques developed at Aberystwyth were used to discover the last time minerals in the sand were exposed to sunlight to determine their age.ĭuller said: “We’re not looking at when the sand was formed – that’s millions of years ago – but when it was deposited.

“That’s important when you’re thinking about building roads, pipelines or any sort of infrastructure,” said Duller. A steady third wind that blows from the east is shifting the dune slowly to the west at a rate of about 50cm a year. Then the climate started to change again and this star dune started to form.”ĭuller said the dune was formed because the wind blows in two opposing directions – from the south-west and the north-east – leading to the sand building up. It seems to have stayed like that for about 8,000 years. We can see traces of old plant roots, suggesting the dune was stabilised by vegetation. The base continued to build up until about 9,000 years ago. “It turned out to be surprisingly young,” said Duller. They discovered that the very base of the dune was 13,000 years old but were surprised that the upper part of the structure had only been formed in the last 1,000 years or so.

The team, which was also made up of University of London academics, travelled to the south-east of Morocco to study a 100-metre high and 700-metre wide dune in the Erg Chebbi sand sea known as Lala Lallia, which means the “highest sacred point” in the Berber language. 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 that make them look like stars.” 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.

Moving stars overlay