Wabar
Craters of black glass in the Empty Quarter.
Key facts
- When
- probably a few hundred years ago
- Where
- Rub' al Khali (the Empty Quarter), Saudi Arabia
- What hit
- an iron meteoroid of perhaps a few thousand tonnes, which broke up in the air
- Era
- In the age of humans
- Location
- 21.50° N, 50.47° E
Probably similar to the Hiroshima bomb, about 10 to 15 kilotons, for the largest crater.
Roughly one Hiroshima bomb, in one of the emptiest places on Earth.
What happened
In 1932 the British explorer Harry St John Philby set out across the great sand desert of Arabia in search of Ubar, a lost city of legend. Guided by Bedouin who spoke of a place called Wabar, he found instead a group of craters surrounded by black glass and white, frothy rock, with pieces of iron lying in the sand.
The craters, two of them more than 60 m across, were made by fragments of an iron meteorite. In 1965 an iron mass of about 2.2 tonnes, called the Camel's Hump, was found there; it is now in Riyadh. Shifting dunes have since covered much of the site.
The black glass is desert sand melted by the impact and mixed with droplets of meteoritic iron and nickel.
Effects
The impact melted and vaporised sand, producing black glass and a white rock made of compacted, shocked sand. The heat and blast would have been felt for kilometres around.
The evidence
Iron meteorite fragments, impact glass with meteoritic metal, and shocked sand.
Did you know?
Wabar is one of very few craters on Earth formed in loose sand.
Its age is uncertain: some studies suggest only a few hundred years, others a few thousand.
Related pages
How is impact energy measured? See energy explained, or try the impact calculator.