Study: Fossil Dunes in Abu Dhabi is Created by Climate Change Dating 200,000 Years Ago

About an hour's drive southeast of Abu Dhabi's city limits, in the direction of the emirate's barren deserts, is a landscape full of unexpected man-made structures.

A stunning oasis-like wetland reserve was produced by a water treatment facility overspill in the Al Wathba area. More along carefully planted tree-lined roads, there is the bizarre sight of an artificial mountain rising on the horizon, its flanks supported by enormous concrete walls. Now it is a lush landscape that draws flocks of migratory flamingos.

Wide and dusty camel highways can be found off of the main roads and in the side streets, where in the cooler evening temperatures vast herds of the humped animals are being worked out in preparation for the winter racing season.

However, one of Al Wathba's more distinctive and beautiful features was not created by people. Abu Dhabi's fossil dunes rise out of the surrounding desert-like frozen waves in a violent ocean made of solid sand, their sides rippling with shapes defined by raging winds. Instead, it has been shaped over tens of thousands of years by elemental forces that provide insight into how the current climate crisis may reshape the world.

More than Just Moisture in the Ground

Even though these proud geological artifacts have endured for centuries in a remote location, the Abu Dhabi Environment Agency opened them as a free tourist attraction in 2022 as part of its efforts to protect them within a protected area.

Instagrammers and other visitors can now choose between two sizable parking lots that are bookended by a trail that meanders past some of the more spectacular landmarks, as opposed to the need for all-terrain vehicles in the past to ride up to the fossil dunes in search of a dramatic selfie backdrop.

There are educational signposts scattered along the route that provide some basic details on the science underlying the development of the dunes.

Thomas Steuber, a professor in the Khalifa University of Science and Technology's Earth Science Department in Abu Dhabi, spent a large portion of the Covid lockdown researching the dunes because he was unable to access other geologically significant locations. He claims that there is much more to it than the conventional theory that says ground moisture caused calcium carbonate in the sand to harden and that strong winds gradually scraped them into peculiar shapes.

According to Steuber, ice ages and thaw cycles that took place between 200,000 and 7,000 years ago produced generations of dunes. Ocean levels fell as polar ice melted, and during these drier times, dunes would have grown as sand blew in from the deserted Arabian Gulf.

In what is now Abu Dhabi, the water table rose as a result of the ice melting and the resulting increase in humidity. The moisture then reacted with the calcium carbonate in the sand to stabilize it and eventually form a kind of cement, which was then whipped into ethereal shapes by prevailing winds.

Weak Material vs. Wind and People

The Arabian Gulf is a tiny, extremely shallow basin, as Steuber noted. Since it is only 120 meters deep, the ocean was dry at the height of the last ice age, about 20,000 years ago, due to the weight of the polar ice caps. As a result, the Gulf, which provided the fossil dunes with their raw materials, was dry.

According to Steuber, it probably took thousands of years for the fossil dunes to form, which are widespread throughout the UAE and can also be found in India, Saudi Arabia, and the Bahamas. However, despite the official protection that is now provided in Abu Dhabi, the erosion that gave each of them their distinctive shapes will eventually cause them to disappear.

Steuber continues by saying that even though some of the fossil dunes are quite large, the wind will eventually destroy them. In essence, they are rocks that occasionally can be broken with bare hands, as it is a weak type of material.

For this reason, visitors to Al Wathba are currently kept away from the dunes, but still close enough to appreciate their impassive beauty.

The journey along the sandy path from the visitor center and gift shop to the parking lot at the other end takes about an hour. Since most people use the shortcut, the return trip is shorter.

However, Stauber and his team from Khalifa University are probably going to return. They are still studying the dunes because there are still a lot of intriguing questions about how sea levels changed during the most recent ice ages, and doing so is crucial for understanding the geomorphology of the Emirates' coastline today. It also clearly serves as a comparison to future sea-level rise.

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