Tabun-Khara-Obo is an impact crater

Impact crater

In the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with a larger body...

 in the Dornogovi Aimag

Dornogovi Province

Dornogovi is one of the 21 Aimags of Mongolia. It is located in the southeast of the country.-Administrative Subdivision:* - tosgon .** - The aimag capital Sainshand-References:...

 (province) the south-east of Mongolia

Mongolia

Mongolia is a landlocked country in East and Central Asia. It is bordered by Russia to the north and China to the south, east and west. Although Mongolia does not share a border with Kazakhstan, its western-most point is only from Kazakhstan's eastern tip. Ulan Bator, the capital and largest...

.
The crater, which is exposed at the surface, is 1.3 km in diameter. The crater's rim rises some 20 to 30 meters above the crater bottom.
It has an estimated age of 150 ± 20 million years (Upper Jurassic

Jurassic

The Jurassic is a geologic period and system that extends from about Mya to  Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...

).The site was first identified as a probable impact crater in 1976, although confirmation of the hypothesis only occurred decades later.
Drilling at the site in 2008 revealed rock features consistent with high-speed impacts such as those caused by meteorites.