These awe-inspiring and enigmatic formations emerge from deserts on Earth and are also present on Mars and Saturn’s largest moon, Titan.

Researchers from various universities, such as Aberystwyth in Wales, have determined the precise age of a star-shaped sand dune located in a secluded region of Morocco. They have also uncovered information about how the dune was formed and its movement patterns across the desert.

Geoff Duller, a professor in Aberystwyth University’s department of geography and earth sciences, described these formations as “extraordinary” and a natural marvel. When viewed from the ground, they appear as pyramids, but from above, they resemble a central peak with arms extending in multiple directions, mimicking the appearance of stars.

A group of University of London researchers journeyed to the southern region of Morocco to examine a dune called Lala Lallia in the Erg Chebbi desert, measuring 100 meters in height and 700 meters in width. Lala Lallia, a term derived from the Berber language, translates to “highest sacred point.”

Rephrased: The researchers found that the bottom of the dune was 13,000 years old, but were astonished to learn that the top part of the dune was only around 1,000 years old. According to Duller, this was unexpectedly young.

Around 9,000 years ago, the base of the formation began to accumulate. After this, the surface reached a point of stability. It is believed that the climate at the time was somewhat more humid than the present day, as indicated by the remains of plant roots found in the dune. This state lasted for approximately 8,000 years. However, the climate eventually shifted once again, causing the development of a star-shaped dune.

“Duller stated that the dune was created by the convergence of two opposite wind patterns– one from the south-west and the other from the north-east– which resulted in the accumulation of sand. The dune is also being gradually moved towards the west by a third consistent wind blowing from the east at a speed of approximately 50cm per year.”

According to Duller, it is essential to consider movement when planning for the construction of roads, pipelines, or other infrastructure projects. These structures are not static and can experience shifts over time.

The Luminescence dating methods, developed at Aberystwyth, were utilized to uncover the most recent instance when the minerals in the sand were exposed to sunlight, in order to determine their age.

According to Duller, our focus is not on the formation date of the sand, which occurred millions of years ago. Rather, we are interested in the date of its deposition. This is because the quartz grains possess a characteristic similar to that of a small rechargeable battery.

This substance has the ability to store energy from natural radioactivity. When retrieved and brought to a lab, the energy can be released in the form of light. The amount of light emitted can then indicate the last time the grain of sand was exposed to sunlight.

The requirement is to acquire the sand particles while keeping them away from light. This was achieved by carving indentations in the sand dunes and inserting a used drainpipe to gather the specimens.

“That part isn’t terribly hi-tech,” said Duller. The work in the lab – which is much more hi-tech and sensitive – has to be carried out in the same sort of conditions as a photographic darkroom.

The luminescence method was utilized to determine the age of remains believed to be from the oldest wooden structure in the world. This structure, consisting of logs along the bank of a river between Zambia and Tanzania, is estimated to have existed before the evolution of modern humans.

The findings about dune exploration were published in the journal Scientific Reports.

Source: theguardian.com