Wabar
Key facts
- Country
- Saudi Arabia
- Diameter
- 116 m
- Age
- probably a few hundred years
- Location
- 21.50° N, 50.47° E
Two small, largely sand-filled craters in the dunes of the Rub' al Khali, surrounded by scattered black glass and white, shocked sandstone; the dunes have buried them almost completely in recent decades.
Wabar lies deep in the Rub' al Khali, the Empty Quarter of Saudi Arabia, the largest sand desert on Earth. It is one of the very few known impact sites in pure sand, and one of the most dramatic, with black glass pearls scattered among the dunes.
A legendary city. In 1932 the British explorer Harry St John Philby crossed the Empty Quarter searching for Wabar, a lost city of Arabian legend said to have been destroyed by fire from heaven for the wickedness of its king. Local guides led him to a place where black glass and scattered stones lay among the dunes. Philby thought he might have found a ruined city or volcanic craters, but the iron fragment he brought back was later identified as meteoritic, showing that the craters were made by a meteorite.
The impact. An iron meteorite broke up as it entered the atmosphere, and its fragments struck the sand. At least two craters formed, the larger about 116 m across and the smaller about 64 m. Since then, wind-blown sand has filled them. Philby's photographs showed them clearly, but later visitors found them shallower, and today they are almost completely buried by the moving dunes.
The age of the craters is uncertain. Studies using different methods have given estimates ranging from a few hundred to several thousand years, with several pointing to a very recent age, only a few centuries ago. The idea that the impact gave rise to the legend is tempting but cannot be proven.
Black pearls and instant rock. Two remarkable materials are found at Wabar. The first is impact glass, formed when the energy of the impact melted the sand. Some of it formed small, shiny black beads known as Wabar pearls, which contain tiny droplets of nickel-iron from the meteorite. The second is a white, crumbly rock sometimes called "instant rock", made from loose sand that was squeezed into sandstone by the shock wave. These shocked sandstones contain features that only form under extreme pressure.
The Camel's Hump. In 1965 a large iron mass weighing about 2.2 tonnes was found near the craters. Nicknamed the Camel's Hump, it is now displayed in Riyadh. The Wabar meteorite is an iron of group IIIAB, a common type.
Visiting. Wabar is extremely remote, hundreds of kilometres from the nearest settlement, and reaching it requires a properly equipped desert expedition. Scientific trips in the 1990s found that the craters were already disappearing under the sand.
Why it matters. Wabar shows how impacts affect loose sand, and how quickly a desert can erase a crater. It is also a reminder that impacts have happened in historical times and may lie behind some legends.
Did you know?
Philby was searching for a legendary lost city when he reached the Wabar craters in 1932.
Black glass beads called Wabar pearls contain tiny droplets of meteoritic iron.
An iron mass of about 2.2 tonnes, the Camel's Hump, was found near the craters in 1965.