{{Short description|Montes on Mars}} {{Infobox feature on celestial object |name = Tharsis Montes |image = Tharsis Montes MOLA zoom 64.jpg |caption = [[Mars Orbiter Laser Altimeter|MOLA]] topographic map of the Tharsis Montes and their surroundings. [[Olympus Mons]] is at upper left; the western end of the [[Valles Marineris]] canyon system, with [[Noctis Labyrinthus]], is at right. |location = Tharsis Region |coordinates = {{coord|1.57|N|112.58|W|globe:mars_type:landmark|display=inline,title}} |peak = Ascraeus Mons (18.2 km) |discoverer = Mariner 9 }}
The '''Tharsis Montes''' ({{IPAc-en|'|T|ɑr|s|ᵻ|s|_|'|m|Q|n|t|iː|z}}) are three large [[shield volcano]]es in the [[Tharsis]] region of the planet [[Mars]]. From north to south, the volcanoes are [[Ascraeus Mons]], [[Pavonis Mons]] and [[Arsia Mons]]. [[Mons (astrogeology)|Mons]] (plural ''montes'') is the Latin word for mountain; it is a [[descriptor term]] used in [[astrogeology]] for mountainous features in the [[Solar System]].
The three Tharsis Montes volcanoes are enormous by terrestrial standards, ranging in diameter from {{convert|375|km|mi|abbr=on}} (Pavonis Mons) to {{convert|475|km|mi|abbr=on}} (Arsia Mons).<ref>{{gpn|5948}}</ref> Ascraeus Mons is the tallest with a summit elevation of over {{convert|18|km|ft|abbr=on}},<ref>Plescia, J.B. (2004). Morphometric Properties of Martian Volcanoes. ''J. Geophys. Res.'' '''109'''(E03003), Table 1.</ref> or {{convert|15|km|ft|abbr=on}} base-to-peak. For comparison, the tallest volcano on Earth, [[Mauna Kea]] in [[Hawaii]], is about {{convert|120|km|mi|abbr=on}} across and stands {{convert|9|km|ft|abbr=on}} above the ocean floor.<ref>Carr, M.H. (2006). ''The Surface of Mars;'' Cambridge University Press: Cambridge, UK, p. 46.</ref>
The Tharsis Montes volcanoes lie near the equator, along the crest of a vast volcanic plateau called the Tharsis region or Tharsis bulge. The Tharsis region is thousands of kilometers across and averages nearly {{convert|10|km|ft|abbr=on}} above the mean elevation of the planet. [[Olympus Mons]], the tallest known [[mountain]] in the Solar System, is located about {{convert|1,200|km|mi|abbr=on}} northwest of the Tharsis Montes, at the edge of the Tharsis region.
The Tharsis Montes were discovered by the [[Mariner 9]] spacecraft in 1971. They were among the few surface features visible as the spacecraft entered orbit during a global dust storm. Appearing as faint spots through the dusty haze, they were informally christened North Spot, Middle Spot, and South Spot. A fourth spot corresponding to the albedo feature Nix Olympica was also visible and later named [[Olympus Mons]]. As the dust cleared, it became obvious that the spots were the tops of enormous [[shield volcano]]es with complex central [[calderas]] (collapse craters).<ref>Masursky, H. (1973). An Overview of Geological Results from Mariner 9. ''J. Geophys. Res.,'' '''78'''(20), 4009–4030.</ref><ref>Carr, M.H. (1973). Volcanism on Mars.'' J. Geophys. Res.'' '''78'''(20), p. 4049-4062.</ref>
The three Tharsis Montes volcanoes are evenly spaced about {{convert|700|km|mi|abbr=on}} apart from peak to peak, in a line oriented from southwest to northeast.<ref>Cattermole, P.J. (2001) ''Mars: the Mystery Unfolds;'' Oxford University Press: New York, p. 72.</ref> This alignment is unlikely to be coincidental. Several smaller volcanic centers northeast of the Tharsis Montes are on an extension of the line. The three volcanoes, most notably Arsia Mons,<ref name="Carr 2006 Rift Zone">{{cite book|last=Carr|first=Michael|title=The Surface of Mars|date=2006|publisher=Cambridge University Press|location=Cambridge, UK|isbn=978-0-511-27041-3|pages=63|url=https://www.scribd.com/doc/77742024/24/Tharsis-Montes}}{{Dead link|date=June 2018 |bot=InternetArchiveBot |fix-attempted=no }}</ref> also all have collapse features and rifts, from which flank eruptions issued, that transect them along the same northeast–southwest trend. The line clearly represents a major structural feature of the planet, but its origin is uncertain.<ref>Carr, M.H. (2006). ''The Surface of Mars;'' Cambridge University Press: New York, p. 70.</ref>
== Gallery == <gallery class="center" widths="190px" heights="180px"> Image:Eastern Tharsis and Noctis Labyrinthus.png|Three volcanoes comprise the Tharsis Montes: [[Arsia Mons]] (in the south), [[Pavonis Mons]] (at center) and [[Ascraeus Mons]] (in the north). Image mosaic is from [[Viking 1]] Orbiter (1980). Image:Arsia Mons mosaic.jpg| Arsia Mons, southernmost peak of Tharsis Montes. Image:Pavonis Mons PIA05243.jpg|Pavonis Mons, the central peak of Tharsis Montes. Image:Ascraeus Caldera Wall PIA05977.jpg|The caldera of Ascraeus Mons, northernmost peak of Tharsis Montes. </gallery>
== See also == {{div col}} * [[Geography of Mars]] * [[List of mountains on Mars by height]] * [[List of tallest mountains in the Solar System]] * [[Tharsis]] plateau * [[True polar wander on Mars]] * [[Volcanism on Mars]] {{Div col end}}
== References == {{Reflist|colwidth=30em}}
==External links== *[http://ic.arc.nasa.gov/ic/projects/bayes-group/Atlas/Mars/features/t/tharsis_montes.html NASA/Ames Mars Atlas feature entry for Tharsis Montes]{{dead link|date=January 2025|bot=medic}}{{cbignore|bot=medic}} *[http://www.google.com/mars/#lat=1.57&lon=-112.58&zoom=4 Tharsis Montes on Google Mars]
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[[Category:Mountains on Mars]] [[Category:Volcanoes of Mars]]