Impactite
Impactite is rock created or modified by one or more impacts of a meteorite.[1][2] Impactites are considered metamorphic rock, because their source materials were modified by the heat and pressure of the impact.[3] On Earth, impactites consist primarily of modified terrestrial material, sometimes with pieces of the original meteorite.[3]
Creation
When a large meteorite hits a planet, it can radically deform the rocks and regolith that it hits. The heat, pressure, and shock of the impact changes these materials into impactite.[3] Only very massive impacts generate the heat and pressure needed to transform a rock, so impactites are created rarely.[3]
Characteristics
Impactite includes
Shocked rock
Shocked rocks have been transformed by shock metamorphism caused by the impact. They include shatter cones and high-pressure minerals, for example coesite and stishovite.
Impact melts
When a meteor strikes a planet's surface, the energy released from the impact can melt rock and soil into a liquid. The liquid then cools and becomes an impact melt.
Impact breccias
Breccia is "a rock consisting of angular fragments cemented together".[6] An impact breccia is formed when a meteor shatters a rock and then cements it back together. Some breccias contain impact melts.[3]
Examples of impactite
Impactite has been found, for example, at the following impact craters and structures:
- Alamo bolide impact (Late Devonian), Nevada, United States
- Barringer crater, Arizona, United States[7]
- Charlevoix impact structure, Québec, Canada
- Darwin Crater, Tasmania (source of Darwin glass)
- Kärnäite)
- Manicouagan impact structure, Québec, Canada
- Neugrund crater, Estonia
- Nördlinger Ries crater, Germany
- Rochechouart impact structure, France
- Stac Fada Member, Scotland
- Wabar craters, Saudi Arabia
See also
References
- Bibcode:1994LPI....25.1347S.
- ^ ISBN 978-0-511-62891-7
- ^ a b c d e "Impactites: Impact Breccia, Tektites, Moldavites, Shattercones". geology.com. Retrieved 2020-06-10.
- ^ a b c Staff (8 June 2015). "PIA19673: Spectral Signals Indicating Impact Glass on Mars". NASA. Retrieved 8 June 2015.
- ^ Temming, Maria. "Exotic Glass Could Help Unravel Mysteries of Mars". Scientific American. Retrieved 2015-06-15.
- ^ Holland, Stuart S. (1976). Landforms of British Columbia: A Physiographic Outline (PDF). British Columbia, Canada. p. 127.
{{cite book}}
: CS1 maint: location missing publisher (link) - ^ Meteor Crater Bomblets
External links