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{{MarsGeo-short description|Crater on Mars}}
{{Infobox crater data
| name=Zunil
| titlecolor = #FA8072
| image = [[Image:Zunil Crater.png|200px|Zunil crater as seen by THEMIS.]]
| title = Zunil
| region = [[Athabasca Valles]]▼
| image = Zunil crater as seen by CTX (cropped).jpg
| diameter = 10.4 km▼
| alt = Zunil crater as seen by CTX
| latitude = 7.8
▲| region = [[Athabasca Valles]]
| N_or_S = N
| coordinate_title = [[Mars#Geography|Coordinates]]
| longitude = 193.9
| E_or_Wglobe = WMars
| coordinates = {{coord|7.8|N|193.9|W|globe:mars_type:landmark|display=inline,title}}
| eponym = [[Zunil]]▼
▲| diameter = {{cvt|10.4 26|km}}
▲| eponym = [[Zunil]], Guatemala
}}
 
'''Zunil''' is an [[impact crater]] near the [[Cerberus Fossae]] on [[Mars]], with a diameter of {{convert|10.426 |km |mi |abbr=onoff |1sigfig=3}}. It is named after the town of [[Zunil|a town]] in Guatemala.<ref>{{GPN|6765}}</ref> The crater is located in the [[GuatemalaElysium quadrangle]]. Visible in images from the [[Viking 1]] and [[Viking 2]] Mars orbiters in the 1970s, Zunil was subsequently imaged at higher resolution for the first time by the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) in 2000.<ref>{{cite web|url=http://www.msss.com/moc_gallery/m19_m23/images/M21/M2100859.html|title=MOC narrow-angle image M21-00859—Crater traverse at 7.8 N 193.8 W|publisher=Malin Space Science Systems|accessdateaccess-date=2001-10-08|url-status=dead|archive-url=https://web.archive.org/web/20030627095935/http://www.msss.com/moc_gallery/m19_m23/images/M21/M2100859.html|archive-date=2003-06-27}}</ref>
 
A ray system associated with the Zunil impact, visible in infrared images from the Mars Odyssey [[Thermal Emission Spectrometer]] (THEMIS) was later detailed by McEwen et al. (2003); prior tobefore this, large craters with ray systems had not been seen on Mars.<ref>{{cite conference|author=McEwen et al.|display-authors=etal|title=Discovery of a large rayed crater on Mars: Implications for recent volcanic and fluvial activity and the origin of Martian meteorites|conference=[[Lunar and Planetary Science Conference]]|date=2003|url=http://www.lpi.usra.edu/meetings/lpsc2003/pdf/2040.pdf}}</ref>
 
The debris from a recent landslide was first spotted on the south-east wall of the crater by the Mars Global Surveyor Mars Orbiter Camera (MOC) in 2003,<ref>{{cite web|url=http://www.msss.com/moc_gallery/r03_r09/images/R08/R0802140.html|title=MOC narrow-angle image R08-02140—Zunil Crater and its ejecta|publisher=Malin Space Science Systems|accessdateaccess-date=2004-04-20|url-status=dead|archive-url=https://web.archive.org/web/20041106110651/http://www.msss.com/moc_gallery/r03_r09/images/R08/R0802140.html|archive-date=2004-11-06}}</ref> and was subsequently imaged at higher resolution by the Mars Reconnaissance Orbiter High Resolution Imaging Science Experiment ([[HiRISE]]) in December 2006.<ref>{{cite web|url=http://hirise.lpl.arizona.edu/PSP_001764_1880|title=Recent Landslide in Zunil Crater (PSP_001764_1880)|publisher=[[University of Arizona]]|accessdateaccess-date=2008-06-28}}</ref>
 
== Formation ==
The impact which formed Zunil occurred no more than a few million years ago and hence the crater is in a relatively pristine form. It was probably not produced in a high velocity impact, such as from a comet. The crater formed in basalt deposited 165 - 177 million years ago.<ref name=icarus />▼
 
▲The impact which formed Zunil occurred no more than a few million years ago and hence the crater is in a relatively pristine form. It was probably not produced in a high -velocity impact, such as from a comet. TheIf the interpretation that Zunil is the source of the basaltic [[Mars meteorite#Shergottites|shergottite meteorites]] is correct, then the crater formed in basalt deposited 165 - 177165–177 million years ago.<ref name=icarus />
The impact created a [[ray system]], visible in the [[infrared]], that extends up to 1600&nbsp;km from the crater and produced hundreds of millions of [[secondary crater]]s with diameters ranging from 10 m to 100 m. Very few of these secondary craters lie within 80&nbsp;km of Zunil. Around 80% of the craters in [[Athabasca Valles]] are Zunil secondaries. If similar impacts also produced comparable amounts of secondaries, this calls into question the accuracy of [[crater counting]] as a dating technique for geologically young Martian surface features.<ref name=icarus>{{cite journal|author=McEwen, A.S. et al.|url=http://www.mars.asu.edu/christensen/classdocs/mcewen_zunil_Icarus_2005.pdf|title=The rayed crater Zunil and interpretations of small impact craters on Mars|journal=[[Icarus (journal)|Icarus]]|volume=176|pages=351–381|year=2005|accessdate=2006-09-08|doi=10.1016/j.icarus.2005.02.009|bibcode=2005Icar..176..351M}}</ref><ref name=science>{{cite journal|title=Who can Read the Martian Clock?|journal=[[Science (journal)|Science]]|author=Kerr, R|volume=312|year=2006|pages=1132–1133|doi=10.1126/science.312.5777.1132|pmid=16728612|issue=5777}}</ref>▼
 
[[ImageFile:Landslide on Mars.jpg|thumb|200px|right|A landslide in the Martian crater Zunil.]]▼
A simulation of the Zunil impact ejected on the order of ten billion rock fragments greater than 10 centimeters in diameter, the total ejecta comprising 30&nbsp;km<sup>3</sup>. These formed about a billion secondary craters 10 m in size up to 3500&nbsp;km away from the primary impact. It is possible that some of these fragments from the impact made it to Earth to become shergottites, a form of [[Martian meteorite]].<ref name=icarus />▼
 
▲The impact created a [[ray system]], visible in the [[infrared]], that extends up to 1600&nbsp;{{cvt|1,600|km}} from the crater and produced hundreds of millions of [[secondary crater]]s with diameters ranging from {{cvt|10 m |to |100 |m}}. Very few of these secondary craters lie within {{cvt|80&nbsp;|km}} of Zunil. Around 80% of the craters in [[Athabasca Valles]] are Zunil secondaries. If similar impacts also produced comparable amounts of secondaries, this calls into question the accuracy of [[crater counting]] as a dating technique for geologically young Martian surface features.<ref name=icarus>{{cite journal|authorlast=McEwen, |first=A.&nbsp;S. et al.|display-authors=etal|url=http://www.mars.asu.edu/christensen/classdocs/mcewen_zunil_Icarus_2005.pdf|title=The rayed crater Zunil and interpretations of small impact craters on Mars|journal=[[Icarus (journal)|Icarus]]|volume=176|pages=351–381|yeardate=2005|accessdateaccess-date=2006-09-08|doi=10.1016/j.icarus.2005.02.009|bibcode=2005Icar..176..351M|issue=2}}</ref><ref name=science>{{cite journal|title=Who can Read the Martian Clock?|journal=[[Science (journal)|Science]]|authorlast=Kerr, |first=R |volume=312|yeardate=2006|pages=1132–1133|doi=10.1126/science.312.5777.1132|pmid=16728612|issue=5777|s2cid=128854527}}</ref>
==See also==▼
▲[[Image:Landslide on Mars.jpg|thumb|200px|right|A landslide in the Martian crater Zunil.]]
*[[List of craters with ray systems]]▼
 
▲A simulation of the Zunil impact ejected on the order of ten billion rock fragments greater than {{convert|10 centimeters|cm}} in diameter, the total ejecta comprising {{cvt|30&nbsp;km<sup>3</sup>|km3}}. These formed about a billion secondary craters 10 m in size up to 3500&nbsp;{{cvt|3,500|km}} away from the primary impact. It is possible that some of these fragments from the impact made it to Earth to become shergottites, a form of [[Martian meteorite]].<ref name=icarus />
==References==▼
 
Research published in the journal ''Icarus'' has found pits in Zunil Crater that are caused by hot ejecta falling on ground containing ice. The pits are formed by heat forming steam that rushes out from groups of pits simultaneously, thereby blowing away from the pit ejecta.<ref>Tornabene, L. et al. 2012. "Widespread crater-related pitted materials on Mars. Further evidence for the role of target volatiles during the impact process". ''Icarus''. 220: 348-368.</ref>
 
▲== See also ==
* [[List of craters on Mars]]
▲* [[List of craters with ray systems]]
 
▲== References ==
{{reflist}}
 
== External links ==
* [http://themis.asu.edu/discoveries-zunilnode/5400 Themis page about Zunil]
* [http://www.psrd.hawaii.edu/Jan07/MarsRayedCraters.html Rayed craters on Mars]
 
{{Geography of Mars}}
{{Portal bar|Solar System}}
 
[[Category:Impact craters on Mars]]
[[Category:Elysium quadrangle]]
[[Category:Extraterrestrial landslides]]
 
[[fr:Zunil (cratère martien)]]
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