Geologic structure formed from impact on a planetary surface
Impact crater structure
An impact structure is a generally circular or craterlike geologic structure of deformed bedrock or sediment produced by impact on a planetary surface, whatever the stage of erosion of the structure. In contrast, an impact crater is the surface expression of an impact structure. In many cases, on Earth, the impact crater has been destroyed by erosion, leaving only the deformed rock or sediment of the impact structure behind.[1] This is the fate of almost all old impact craters on Earth, unlike the ancient pristine craters preserved on the Moon and other geologically inactive rocky bodies with old surfaces[2] in the Solar System. Impact structure is synonymous with the less commonly used term astrobleme meaning "star wound".[3]
In an impact structure, the typical visible and topographic expressions of an impact crater are no longer obvious. Any meteorite fragments that may once have been present would be long since eroded away. Possible impact structures may be initially recognized by their anomalous geological character or geophysical expression. These may still be confirmed as impact structures by the presence of shocked minerals (particularly shocked quartz), shatter cones, geochemical evidence of extraterrestrial material or other methods.
^Neuendorf, K.K.E., J.P. Mehl Jr., and J.A. Jackson, eds. (2005) Glossary of Geology (5th ed.). Alexandria, Virginia, American Geological Institute. 779 pp. ISBN 0-922152-76-4
^Moore, Jeffrey M.; Black, Greg; Buratti, Bonnie; Phillips, Cynthia B.; Spencer, John; Sullivan, Robert (2009). "Surface Properties, Regolith, and Landscape Degradation". In Pappalardo, Robert T. (ed.). Europa. The University of Arizona space science series. McKinnon, William B.; Khurana, Krishan. Tucson: The University of Arizona Press. p. 341. ISBN 978-0-8165-2844-8. Bodies with current geological activity such as Io and Earth have very few recognizable impact craters—Io, in fact, is so volcanically active that not a single impact crater, of any size, has been found on its surface to date. The Earth has about 150 recognized craters, but many have been geologically modified and would be difficult to recognize from orbit. On the other hand, geologically inactive bodies with old surfaces, such as Earth's Moon or Callisto, are covered with impact craters of all sizes.
^French, Bevan M (1998). Traces of Catastrophe: A Handbook of Shock-Metamorphic Effects in Terrestrial Meteorite Impact Structures. Houston, Texas: Lunar and Planetary Institute. p. 120. LPI Contribution No. 954.
An impactstructure is a generally circular or craterlike geologic structure of deformed bedrock or sediment produced by impact on a planetary surface...
kilometers (12 miles) in depth. It is the second largest confirmed impactstructure on Earth, and the only one whose peak ring is intact and directly accessible...
The Yarrabubba impactstructure is the eroded remnant of an impact crater, situated in the northern Yilgarn Craton near Yarrabubba Station between the...
The Popigai impactstructure is the eroded remnant of an impact crater in northern Siberia, Russia. It is tied with the Manicouagan structure as the fourth...
coordinates) This list of impactstructures on Earth contains a selection of the 190 confirmed craters given in the Earth Impact Database as of 2017. To...
Charlevoix impactstructure is a large eroded meteorite impactstructure in the Charlevoix region of Quebec, Canada. Only part of the impactstructure is exposed...
Dhala crater (N25°17'59.7" and E78°8'3.1") is an impactstructure formed by an asteroid impact. It is situated near Bhonti village in Pichhore block of...
The Beaverhead impactstructure is the second largest impactstructure within the U.S. It lies within the states of Idaho and Montana. Estimated at 60...
Shoemaker (formerly known as Teague Ring) is an impactstructure, the deeply eroded remnant of a former impact crater, situated in arid central Western Australia...
Acraman impactstructure is a deeply eroded impact crater in the Gawler Ranges of South Australia. Its location is marked by Lake Acraman, a circular ephemeral...
The Manson impactstructure is an impactstructure near the site of Manson, Iowa where an asteroid or comet nucleus struck the Earth during the Cretaceous...
Rochechouart impactstructure or Rochechouart astrobleme is an impactstructure in France. Erosion has over the millions of years mostly destroyed its impact crater...
Tookoonooka is a large meteorite impactstructure (astrobleme) situated in South West Queensland, Australia. It lies deeply buried within Mesozoic sedimentary...
Carswell is an impactstructure within the Athabasca Basin of the Canadian Shield in northern Saskatchewan, Canada. It is 39 kilometres (24 mi) in diameter...
Woodleigh is a large meteorite impactstructure (astrobleme) in Western Australia, centred on Woodleigh Station east of Shark Bay, Gascoyne region. A team...
The Morokweng impactstructure is an impactstructure buried beneath the Kalahari Desert near the town of Morokweng in South Africa's North West province...
Saint Martin is an impactstructure in Manitoba, Canada. It is located in the northern part of the Rural Municipality of Grahamdale, northwest of Lake...
Steen River is an impactstructure in Alberta, Canada. It is 25 km (16 mi) in diameter and the age is estimated to be 91 ± 7 million years (Late Cretaceous)...
in Canada, there are 190 confirmed impactstructures on Earth. Each is recorded in a database called the Earth Impact Database (EID). Map all coordinates...
groundwater contamination. Toms Canyon structure probable impact crater 322 km (200 mi) to the northeast. Popigai impactstructure of similar age Grande Coupure...
The Tunnunik impactstructure, formerly known as the Prince Albert Impact Crater, is a recently confirmed meteorite impactstructure. It is located on...
includes all 27 confirmed impactstructures in Australia as listed in the Earth Impact Database. The following structures are officially considered "unconfirmed"...
the structure was done in the 1990s. A study of the formation of the structure by Matton, et al. (2005, 2008) concluded it was not an impactstructure. Further...
highest point is Mount Babel. The structure was created 214 (±1) million years ago, in the Late Triassic, by the impact of a meteorite 5 km (3 mi) in diameter...
topography, the terms impactstructure or astrobleme are more commonly used. In early literature, before the significance of impact cratering was widely...
In early 2018 there were eight known impactstructures in Sweden. They range in age from 90 mya to 470 mya, and in diameter from 1 km to 52 km. Six of...
coordinates) This list of impactstructures in Africa includes all 20 confirmed impact craters as listed in the Earth Impact Database. These features were...
for an Earth impacting body), though atmospheres mitigate many surface impacts through atmospheric entry. Impact craters and structures are dominant landforms...
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