Dalgaranga crater
Encyclopedia
Dalgaranga crater is a small meteorite
impact crater
located on Dalgaranga pastoral station 75 km west of Mount Magnet
(or north of Yalgoo
) in Western Australia
. It is only 24 m in diameter and 3 m deep, making it Australia's smallest impact crater (with exception of the smallest members of the Henbury crater field). Though reputedly discovered much earlier, it was first reported in the scientific literature in 1938. The bedrock at the site is weathered Archaean granite
of the Yilgarn Craton
. The discovery of fragments of mesosiderite
stony-iron meteorite around the crater confirms an impact origin, making this crater unique as the only one known to have been produced by a mesosiderite projectile. Asymmetries in the crater structure and the ejecta blanket imply that the projectile impacted at low angle from the south-southeast. The age is not accurately constrained but must be young because it is so well preserved for its small size, and the meteorite fragments have not weathered away; some authors suggest an age of as young as 3000 years.
Meteorite
A meteorite is a natural object originating in outer space that survives impact with the Earth's surface. Meteorites can be big or small. Most meteorites derive from small astronomical objects called meteoroids, but they are also sometimes produced by impacts of asteroids...
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...
located on Dalgaranga pastoral station 75 km west of Mount Magnet
Mount Magnet, Western Australia
Mount Magnet is an old Western Australian gold rush town. The name was chosen during exploration of the region due to an isolated hill 5 km north west of the town current townsite. This hill has an extremely high iron content and affected the compasses of explorers...
(or north of Yalgoo
Yalgoo, Western Australia
-Further reading:* Palmer, Alex. Yalgoo Fremantle, W.A: Lap Industries. ISBN 0959058400- See also :* Yalgoo - the ecological region* Thundelarra* Shire of Yalgoo - the local government region...
) in Western Australia
Western Australia
Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...
. It is only 24 m in diameter and 3 m deep, making it Australia's smallest impact crater (with exception of the smallest members of the Henbury crater field). Though reputedly discovered much earlier, it was first reported in the scientific literature in 1938. The bedrock at the site is weathered Archaean granite
Granite
Granite is a common and widely occurring type of intrusive, felsic, igneous rock. Granite usually has a medium- to coarse-grained texture. Occasionally some individual crystals are larger than the groundmass, in which case the texture is known as porphyritic. A granitic rock with a porphyritic...
of the Yilgarn Craton
Yilgarn craton
The Yilgarn Craton is a large craton which constitutes the bulk of the Western Australian land mass. It is bounded by a mixture of sedimentary basins and Proterozoic fold and thrust belts...
. The discovery of fragments of mesosiderite
Mesosiderite
Mesosiderites are a class of stony–iron meteorites consisting of about equal parts of metallic nickel-iron and silicate. They are breccias with an irregular texture; silicates and metal occur often in lumps or pebbles as well as in fine-grained intergrowths...
stony-iron meteorite around the crater confirms an impact origin, making this crater unique as the only one known to have been produced by a mesosiderite projectile. Asymmetries in the crater structure and the ejecta blanket imply that the projectile impacted at low angle from the south-southeast. The age is not accurately constrained but must be young because it is so well preserved for its small size, and the meteorite fragments have not weathered away; some authors suggest an age of as young as 3000 years.