Starfish Dunes - What's the Mystery behind them ?

[Frederic]

For the first time, scientists have been able to determine the age of a star dune, one of the largest dune species. The Lala Lallia was formed in Morocco 13,000 years ago, and today it still moves slowly through the desert.

Star dunes such as the Lala Lallia (Berber for 'Highest Sacred Point') can grow up to hundreds of meters high. They are found in Africa, Asia and North America, as well as outside the Earth, such as on Mars. The Lala Lallia is 100 meters high and 700 meters wide and is located in the desert area of Erg Chebbi in the southeast of Morocco.

In the UAE, there are hundreds of these types of dunes, mostly found in the Al Quoa Region: https://maps.app.goo.gl/qaeHbLqc6zQyvV3f8

Such a dune is created by winds from different directions colliding with each other. From the ground, such a dune looks like a pyramid (hence the nickname 'pyramid dune'. But from the sky, the dune looks more like a star, because it flares out in several arms. By finding out their age, scientists can learn to understand the workings of those winds and better map the climate of thousands of years ago. Understanding how the dunes form also has a practical use in the construction of infrastructure such as roads or pipelines.

The Lala Lallia now appears to be 13,000 years old. That seems very old, but in geological terms, 13,000 years is pretty young. And to the researchers' surprise, the top layer of the dune was much younger, 'barely' a thousand years old. By the way, the sand that makes up the dune is much older: millions of years, in fact.

Scientists were able to determine the age using the technique of luminescence dating, in which they calculate when grains of sand were last exposed to daylight. According to the scientists, the dune formed relatively quickly, in 4,000 years. After that, the dune stopped growing for about 8,000 years, only to expand again in the last thousand years.

Because dune formation is so strongly dependent on the wind, a dune never stands completely still. According to the researchers, the Lala Lallia shifts fifty centimeters every year. Geoff Duller, a professor involved at the University of Aberystwyth in Wales, called the dunes "extraordinary" and "one of the natural wonders of the world".

 

 

[DP1011]

Great insights @Frederic ! Always have been hearing about them but got to know this detailed finally ! 

In terms of difficulty level  - Is it more IM level or super technical with associated risks to do these ? Or super easy and fun ! 

[Frederic]

Definitely not for beginner level  

you can either do massive sideys on the flanks, or cross over the ridges that branch out. 

[M.Seidam]

In waqan there are lots of these