Mundrabilla

Two giant iron masses found on Australia's Nullarbor Plain in 1966, packed with unusual sulphide nodules.

Key facts

Type

Iron, IAB complex (ungrouped member), rich in troilite

Fell or found

Found

Year

1911 (first fragments); main masses 1966

Country

Australia (Western Australia)

Mass

two main masses of roughly 11–12 tonnes and about 5 tonnes, plus many smaller pieces

Official name

Mundrabilla

The Nullarbor Plain in southern Australia is one of the flattest, driest landscapes on Earth. Its name comes from Latin words meaning 'no trees', and its pale limestone surface stretches for hundreds of kilometres along the Great Australian Bight. It is also one of the best places in the world to find meteorites, because dark rocks stand out clearly against the pale ground and the dry climate slows weathering. In this setting lies Mundrabilla, the largest meteorite ever found in Australia.

From fragments to giants

Small iron fragments were noticed in the area as early as 1911. But the real treasure was found in 1966, when geologists spotted two enormous iron masses lying close together on the plain. The larger weighed roughly 11 to 12 tonnes, and the smaller about 5 tonnes. They were recovered from the plain, and the Western Australian Museum holds major parts of them. Many smaller fragments have been found in the surrounding area since.

An iron full of nodules

Mundrabilla is an iron meteorite with an unusual make-up. Instead of being almost pure metal, it contains a large amount of troilite, an iron sulphide mineral, in big rounded and elongated nodules set within the iron-nickel metal. When cut and polished, slices show a striking patchwork of bronze-coloured troilite and silvery metal. Etched surfaces reveal the Widmanstätten pattern of metal crystals that grew as the metal cooled.

Chemically, Mundrabilla is related to the IAB complex of iron meteorites, a varied family thought to have formed differently from most iron meteorites. Instead of crystallising in the deep core of a fully melted asteroid, IAB-type irons may have formed in pools of molten metal and sulphide produced by impacts on a partly melted body. Mundrabilla's abundant sulphide gives scientists a rare chance to study how metal and sulphide liquids separated and crystallised together. Researchers compare its chemistry with that of other members of the family, such as Canyon Diablo and Campo del Cielo, to understand how varied these irons are.

Lying on the plain

No crater has been found at Mundrabilla, and the masses were lying on or near the surface. The meteorite probably fell a very long time ago. On the Nullarbor, rates of erosion and weathering are slow, so meteorites can survive for many thousands of years. The plain has yielded hundreds of other meteorites as well, many of them stony meteorites collected during systematic searches.

Why it matters

Mundrabilla is important for several reasons. Its size places it among the largest iron meteorites known anywhere. Its unusual composition, especially its abundant troilite, makes it a valuable sample for understanding how metal-rich bodies formed and evolved in the early Solar System. And its story highlights the role of the Australian outback as a natural meteorite collection site.

Meteorites found in Western Australia are protected by law, and finds must be reported to the Western Australian Museum. This ensures that important specimens remain available for science and for the public. Anyone exploring remote areas should also be well prepared: the Nullarbor can be dangerously hot and isolated.

Seeing Mundrabilla

Slices of Mundrabilla are held in museums and research collections in Australia and abroad, and the Western Australian Museum has displayed parts of the giant masses to the public. Standing beside one, it is hard not to be impressed by the thought that this block of iron, as heavy as a lorry, once floated in space as part of a much larger asteroid.

Mundrabilla is a reminder that meteorites can lie quietly in remote places for a very long time, waiting for the right people to recognise them.

Did you know?

See more

Mundrabilla in the catalogue