Impact structure
An impact structure is a generally circular or craterlike
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.
See also
- Complex crater
- Earth Impact Database
- Multi-ringed basin
- Impact event
- List of impact craters on Earth
- List of possible impact structures on Earth
- Traces of Catastrophe book from Lunar and Planetary Institute - comprehensive reference on impact crater science
- Peak ring
References
- ISBN 0-922152-76-4
- ISBN 978-0-8165-2844-8., are covered with impact craters of all sizes.
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
- ^ 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.
External links
- Terrestrial Impact Craters at the Lunar and Planetary Institute
- Earth Impact Database