Veevers crater
Encyclopedia
Veevers crater is an impact crater
located on a flat desert plain between the Great Sandy
and Gibson Desert
s in the center of the state of Western Australia
, Australia
. The site is very remote and difficult to visit. The crater was discovered in July 1975 during a government geological survey and named in honor of Australian John James Veevers who had worked in the area in the late 1950s. At the time of discovery a meteorite impact origin was suspected, but could not be proven. The subsequent discovery of iron meteorite
fragments around the crater by E.M.
and C.S. Shoemaker
in 1984 removed any doubt about its origin.
The crater has a symmetrical bowl-shaped topography and is considered to be one of the best preserved small meteorite craters on Earth. The 20 m wide rim rises about 1.5 m above the plain, while the deepest point of the central depression is 7 m below the rim crest; the rim to rim diameter averages about 70 m. Based on cosmogenic nuclide
exposure dating of the crater walls, the crater is less than 20 thousand years old, while the pristine state of preservation of the ejecta
has been used to suggest that it may in fact be less than 4 thousand years old.
The iron meteorite
fragments collected around the crater are classified as a coarse octahedrite
belonging to chemical class IIAB; the fragments show considerable evidence of deformation presumably related to the impact explosion. It has been inferred that the original meteorite was in the size range of 100-1000 tonnes, probably closer to the latter, now dispersed as fragments within the crater breccia
and ejecta.
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 a flat desert plain between the Great Sandy
Great Sandy Desert
The Great Sandy Desert is a desert located in the North West of Western Australia straddling the Pilbara and southern Kimberley regions. It is the second largest desert in Australia after the Great Victoria Desert and encompasses an area of...
and Gibson Desert
Gibson Desert
The Gibson Desert covers a large dry area in the state of Western Australia and is still largely in an almost "pristine" state. It is about in size, making it the 5th largest desert in Australia, after the Great Sandy, Great Victoria, Tanami and Simpson deserts.-Location and description:The Gibson...
s in the center of the state of 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...
, Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
. The site is very remote and difficult to visit. The crater was discovered in July 1975 during a government geological survey and named in honor of Australian John James Veevers who had worked in the area in the late 1950s. At the time of discovery a meteorite impact origin was suspected, but could not be proven. The subsequent discovery of iron meteorite
Iron meteorite
Iron meteorites are meteorites that consist overwhelmingly of nickel-iron alloys. The metal taken from these meteorites is known as meteoric iron and was one of the earliest sources of usable iron available to humans.-Occurrence:...
fragments around the crater by E.M.
Eugene Merle Shoemaker
Eugene Merle Shoemaker , American geologist, was one of the founders of the fields of planetary science....
and C.S. Shoemaker
Carolyn S. Shoemaker
Carolyn Jean Spellmann Shoemaker is an American astronomer and is a co-discoverer of Comet Shoemaker–Levy 9. She holds the record for most comets discovered by an individual.- Personal life :...
in 1984 removed any doubt about its origin.
The crater has a symmetrical bowl-shaped topography and is considered to be one of the best preserved small meteorite craters on Earth. The 20 m wide rim rises about 1.5 m above the plain, while the deepest point of the central depression is 7 m below the rim crest; the rim to rim diameter averages about 70 m. Based on cosmogenic nuclide
Nuclide
A nuclide is an atomic species characterized by the specific constitution of its nucleus, i.e., by its number of protons Z, its number of neutrons N, and its nuclear energy state....
exposure dating of the crater walls, the crater is less than 20 thousand years old, while the pristine state of preservation of the ejecta
Ejecta
Ejecta can mean:*In volcanology, particles that came out of a volcanic vent, traveled through the air or under water, and fell back on the ground surface or on the ocean floor...
has been used to suggest that it may in fact be less than 4 thousand years old.
The iron meteorite
Iron meteorite
Iron meteorites are meteorites that consist overwhelmingly of nickel-iron alloys. The metal taken from these meteorites is known as meteoric iron and was one of the earliest sources of usable iron available to humans.-Occurrence:...
fragments collected around the crater are classified as a coarse octahedrite
Octahedrite
Octahedrites are a class of iron meteorites within the structural classification. They are the most common class of iron meteorites.They are composed primarily of the nickel-iron alloys: taenite - high nickel content, and kamacite - low nickel content....
belonging to chemical class IIAB; the fragments show considerable evidence of deformation presumably related to the impact explosion. It has been inferred that the original meteorite was in the size range of 100-1000 tonnes, probably closer to the latter, now dispersed as fragments within the crater breccia
Breccia
Breccia is a rock composed of broken fragments of minerals or rock cemented together by a fine-grained matrix, that can be either similar to or different from the composition of the fragments....
and ejecta.