multi-ringed basin
{{Short description|Crater containing multiple concentric topographic rings}}
File:Valhalla Basin from Voyager 1.jpg on Jupiter's moon Callisto, taken by Voyager 1]]
A multi-ringed basin (also a multi-ring impact basin) is not a simple bowl-shaped crater, or a peak ring crater, but one containing multiple concentric topographic rings;{{cite journal |last1=Head |first1=J. W. |title=Transition from complex craters to multi-ringed basins on terrestrial planetary bodies: Scale-dependent role of the expanding melt cavity and progressive interaction with the displaced zone |journal=Geophysical Research Letters |date=January 2010 |volume=37 |issue=2 |doi=10.1029/2009GL041790 |bibcode=2010GeoRL..37.2203H }} a multi-ringed basin could be described as a massive impact crater, surrounded by circular chains of mountains{{cite web | url=http://www.spacegrant.hawaii.edu/class_acts/LunarLandformsTe.html | title=Lunar Landforms Teacher Page | publisher=Hawai'i Space Grant Consortium, Hawai'i Institute of Geophysics and Planetology, University of Hawai'i | date=1998 | accessdate=18 January 2019 | archive-date=12 February 2018 | archive-url=https://web.archive.org/web/20180212070459/http://www.spacegrant.hawaii.edu/class_acts/LunarLandformsTe.html | url-status=dead }} resembling rings on a bull's-eye. A multi-ringed basin may have an area of many thousands of square kilometres.{{cite encyclopedia | chapter-url=https://www.britannica.com/science/multiringed-basin | chapter=Multiringed basin | title=Encyclopedia Britannica | date= February 1, 2018 | accessdate=January 20, 2019}}
An impact crater of diameter bigger than about {{convert|180|mi|km}} is referred to as a basin.{{cite web |url=https://www.ineffableisland.com/2016/10/how-multi-ring-craters-form-revealed-by.html |url-status=usurped |archive-url=https://web.archive.org/web/20170701232331/https://www.ineffableisland.com/2016/10/how-multi-ring-craters-form-revealed-by.html |archive-date=1 July 2017 | title=How Multi-Ring Craters Form Revealed by New Research | work=Ideas, Inventions And Innovations| date=October 29, 2016 }}{{self-published inline|date=May 2024}}
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Structure
More common peak ring craters have: (1) a peak-ring, i.e., a crater rim, which is generally circular, and; (2) a mountainous region which surrounds the center of the crater basin. In contrast, a multi-ringed basin has multiple peak-rings displaying as further concentric circles.
In extremely large collisions, the rebound of the surface after impact can obliterate any trace of the initial impact point. Usually, a peak ring crater has a high structure with a terrace and has slump structures inside of it.
In adjacent rings, the ratio of the diameters approximates {{sqrt|2}}:1 ≈ 1.41 to 1.{{cite encyclopedia | url=https://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/multi-ring-basin | title=Multi-Ring Basin | encyclopedia=Encyclopedia.com | accessdate=January 20, 2019}}Moons & Planets, William K. Hartmann, 2005, p.255ff{{cite thesis |last=Martellato |first=Elena | url=http://paduaresearch.cab.unipd.it/3826/1/elena_THESIS.pdf | title=The importance of being a crater: A tool in planetary surface analysis and datation | publisher=Università degli Studi di Padova |type=PhD Thesis | date=January 31, 2011 | accessdate=January 20, 2019}}
Formation
File:Mare Orientale (Lunar Orbiter 4).png, on Earth's Moon]]
Multi-ring basins are some of the largest, oldest, rarest and least understood of impact craters. There are various hypotheses to explain the formation of multi-ringed basins, however there is currently no consensus.{{cite journal |last1=Potter |first1=Ross W.K. |title=Investigating the onset of multi-ring impact basin formation |journal=Icarus |date=November 2015 |volume=261 |pages=91–99 |doi=10.1016/j.icarus.2015.08.009 |bibcode=2015Icar..261...91P }}{{cite book |author=Stuart Ross Taylor |year=1982 |chapter-url=https://www.lpi.usra.edu/publications/books/planetary_science/chapter3.pdf | chapter=Meteorite impacts, craters and multi-ring basins |title=Planetary Science: A Lunar Perspective |publisher=Lunar and Planetary Institute | accessdate=19 January 2019}}
In 2016, research brought forward new hypotheses about the formation of the lunar mare called Mare Orientale on Earth's Moon.{{cite web | url=https://news.brown.edu/articles/2016/10/orientale | title=Research helps explain formation of ringed crater on the Moon | work=News from Brown | date=October 27, 2016 | accessdate=20 January 2019 | author=Stacey, Kevin}} Prior to this research, the most accepted explanation was the 'slumping/megaterrace' model, which suggested that a deep bowl-shaped basin forms during the impact and that subsidence along faults later produces the ring formations, though this hypothesis was always considered problematic because of evidence that the rings were produced simultaneously with the impact that formed the basin.{{rp|80-81}} The new research produced a model confirming instantaneous formation of all rings, a mechanism in which ductile subsurface rocks flowed towards the center of the basin as the crust rebounded, causing concentric cracking and slippage that formed the outer rings, and that the unstable central peak collapsing formed the inner ring.
Examples
- Mare Orientale on Earth's Moon is a multi-ringed basin created by an impactor perhaps {{convert|40|mi|km|order=flip|-1}} in diameter traveling at {{convert|9|mi/s|km/s|order=flip}}, or about {{convert|32,400|mph|km/h|order=flip}}{{cite web | url=https://news.mit.edu/2016/retracing-origins-massive-multi-ring-crater-moon-1027 | title=Retracing the origins of a massive, multi-ring crater | work=MIT News | date=October 27, 2016 | accessdate=20 January 2019 | last=Chu |first=Jennifer}}
- Anubis on Ganymede, the largest moon of Jupiter
- Valhalla on Callisto, a moon of Jupiter
- Evander on Dione, a moon of Saturn
- Caloris Basin, surrounded by Caloris Montes, on Mercury
- Burney on Pluto, a dwarf planet in the Kuiper belt
Chicxulub crater in Mexico has a sufficient area to have been a multi-ringed basin.{{cite book |first1=W. B. |last1=McKinnon |first2=J. S. |last2=Alexopoulos | chapter=Some implications of large impact craters and basins on Venus for terrestrial ringed craters and planetary evolution |title=KT Event and Other Catastrophes |date=January 1994 |hdl=2060/19940023803}}
See also
- {{annotated link|Complex crater}}
- {{annotated link|Impact crater}}
- {{annotated link|Impact event}}
- {{annotated link|Impact structure}}
- {{annotated link|Peak ring (crater)}}
- {{annotated link|Pedestal crater}}
- {{annotated link|Expanded crater}}
- {{annotated link|Traces of Catastrophe}} book from Lunar and Planetary Institute - comprehensive reference on impact crater science