Zunil (crater)

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Zunil
Zunil Crater.png
Planet Mars
Region Athabasca Valles
Coordinates 7°48′N193°54′W / 7.8°N 193.9°W / 7.8; -193.9
Quadrangle Elysium
Diameter 10.26 km (6.38 mi)
Eponym Zunil, Guatemala

Zunil is an impact crater near the Cerberus Fossae on Mars, with a diameter of 10.26 kilometres (6.38 miles). It is named after the town of Zunil in Guatemala. [1] The crater is located in the Elysium 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. [2]

Contents

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); before this, large craters with ray systems had not been seen on Mars. [3]

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, [4] and was subsequently imaged at higher resolution by the Mars Reconnaissance Orbiter High Resolution Imaging Science Experiment (HiRISE) in December 2006. [5]

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. If the interpretation that Zunil is the source of the basaltic shergottite meteorites is correct, then the crater formed in basalt deposited 165–177 million years ago. [6]

Zunil Crater as seen by MRO's CTX camera Wikizunil.jpg
Zunil Crater as seen by MRO's CTX camera

The impact created a ray system, visible in the infrared, that extends up to 1,600 km (990 mi) from the crater and produced hundreds of millions of secondary craters with diameters ranging from 10 to 100 m (33 to 328 ft). Very few of these secondary craters lie within 80 km (50 mi) 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. [6] [7]

A simulation of the Zunil impact ejected on the order of ten billion rock fragments greater than 10 centimetres (3.9 in) in diameter, the total ejecta comprising 30 km3 (7.2 cu mi). These formed about a billion secondary craters 10 m in size up to 3,500 km (2,200 mi) 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. [6]

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. [8]

See also

A landslide in the Martian crater Zunil. Landslide on Mars.jpg
A landslide in the Martian crater Zunil.

Related Research Articles

<span class="mw-page-title-main">Martian meteorite</span> Meteorite made of rock originating from Mars

A Martian meteorite is a rock that formed on Mars, was ejected from the planet by an impact event, and traversed interplanetary space before landing on Earth as a meteorite. As of September 2020, 277 meteorites had been classified as Martian, less than half a percent of the 72,000 meteorites that have been classified. The largest complete, uncut Martian meteorite, Taoudenni 002, was recovered in Mali in early 2021. It weighs 14.5 kilograms and is on display at the Maine Mineral & Gem Museum.

<span class="mw-page-title-main">Memnonia quadrangle</span> Map of Mars

The Memnonia quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The Memnonia quadrangle is also referred to as MC-16.

<span class="mw-page-title-main">Ejecta blanket</span> Symmetrical apron of ejecta that surrounds an impact crater

An ejecta blanket is a generally symmetrical apron of ejecta that surrounds an impact crater; it is layered thickly at the crater's rim and thin to discontinuous at the blanket's outer edge. The impact cratering is one of the basic surface formation mechanisms of the solar system bodies and the formation and emplacement of ejecta blankets are the fundamental characteristics associated with impact cratering event. The ejecta materials are considered as the transported materials beyond the transient cavity formed during impact cratering regardless of the state of the target materials.

<span class="mw-page-title-main">Crater counting</span>

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<span class="mw-page-title-main">Tooting (crater)</span> Volcanic crater on Mars

Tooting is an impact crater with volcanic features at 23.1°N, 207.1°E, in Amazonis Planitia, due west of the volcano Olympus Mons, on Mars. It was identified by planetary geologist Peter Mouginis-Mark in September 2004. Scientists estimate that its age is on the order of hundreds of thousands of years, which is relatively young for a Martian crater. A later study confirms this order of magnitude estimate. A preliminary paper describing the geology and geometry of Tooting was published in 2007 by the journal Meteoritics and Planetary Science, vol. 42, pages 1615–1625. Further papers have been published, including a 2010 analysis of flows on the walls of Tooting crater by A. R. Morris et al., and a 2012 review paper by P.J. Mouginis-Mark and J.M. Boyce in Chemie der Erde Geochemistry, vol. 72, p. 1–23. A geologic map has also been submitted in 2012 to the U.S. Geological Survey for consideration and future publication.

<span class="mw-page-title-main">Athabasca Valles</span> Outflow channel on Mars

The Athabasca Valles are a late Amazonian-period outflow channel system in the central Elysium Planitia region of Mars, located to the south of the Elysium Rise. They are part of a network of outflow channels in this region that are understood to emanate from large fissures in the Martian surface rather than the chaos terrains that source the circum-Chryse outflow channels. The Athabasca Valles in particular emanate from one of the Cerberus Fossae fissures and flow downstream to the southwest, constrained to the south by a wrinkle ridge for over 100 km, before debouching into the Cerberus Palus volcanic plain. The Athabasca Valles are widely understood to be the youngest outflow channel system on the planet.

<span class="mw-page-title-main">Noachis quadrangle</span> Map of Mars

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<span class="mw-page-title-main">Elysium quadrangle</span> One of 30 quadrangle maps of Mars used by the US Geological Survey

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<span class="mw-page-title-main">Amazonis quadrangle</span> Map of Mars

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<span class="mw-page-title-main">Tharsis quadrangle</span> Map of Mars

The Tharsis quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The Tharsis quadrangle is also referred to as MC-9 . The name Tharsis refers to a land mentioned in the Bible. It may be at the location of the old town of Tartessus at the mouth of Guadalquivir.

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<span class="mw-page-title-main">Margaritifer Sinus quadrangle</span> One of a series of 30 quadrangle maps of Mars

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<span class="mw-page-title-main">Thaumasia quadrangle</span> Map of Mars

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<span class="mw-page-title-main">Mare Australe quadrangle</span> Map of Mars

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<span class="mw-page-title-main">Trouvelot (Martian crater)</span> Crater on Mars

Trouvelot is a crater on Mars, located in the Oxia Palus quadrangle at 16.2° north latitude and 13.1° west longitude near the crustal dichotomy in the circum-Chryse region. It is roughly located along the dichotomy between Arabia Terra to the northeast and the southernmost of the circum-Chryse outflow channels to the southwest. Trouvelot crater measures approximately 148.77 kilometres (92.44 mi) in diameter and was named after Étienne Léopold Trouvelot, a French astronomer (1827–1895). The name was adopted by IAU's Working Group for Planetary System Nomenclature in 1973.

<span class="mw-page-title-main">Arandas (crater)</span> Crater on Mars

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<span class="mw-page-title-main">Mojave (crater)</span> Crater on Mars

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<span class="mw-page-title-main">Resen (crater)</span>

Resen is a crater in the Mare Tyrrhenum quadrangle on Mars, located at 28.22° South and 251.13° West. It is measures 7.4 kilometers in diameter and was named after the town of Resen in North Macedonia. The naming was approved by IAU's Working Group for Planetary System Nomenclature on 19 January 2011.

There are a number of different types of craters that have been observed and studied on Mars. Many of them are shaped by the effects of impacts into ice-rich ground.

References

  1. "Zunil (crater)". Gazetteer of Planetary Nomenclature. USGS Astrogeology Research Program.
  2. "MOC narrow-angle image M21-00859—Crater traverse at 7.8 N 193.8 W". Malin Space Science Systems. Archived from the original on 2003-06-27. Retrieved 2001-10-08.
  3. McEwen; et al. (2003). Discovery of a large rayed crater on Mars: Implications for recent volcanic and fluvial activity and the origin of Martian meteorites (PDF). Lunar and Planetary Science Conference.
  4. "MOC narrow-angle image R08-02140—Zunil Crater and its ejecta". Malin Space Science Systems. Archived from the original on 2004-11-06. Retrieved 2004-04-20.
  5. "Recent Landslide in Zunil Crater (PSP_001764_1880)". University of Arizona . Retrieved 2008-06-28.
  6. 1 2 3 McEwen, A. S.; et al. (2005). "The rayed crater Zunil and interpretations of small impact craters on Mars" (PDF). Icarus . 176 (2): 351–381. Bibcode:2005Icar..176..351M. doi:10.1016/j.icarus.2005.02.009 . Retrieved 2006-09-08.
  7. Kerr, R (2006). "Who can Read the Martian Clock?". Science . 312 (5777): 1132–1133. doi:10.1126/science.312.5777.1132. PMID   16728612. S2CID   128854527.
  8. 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.