Tartarus Colles

{{Short description|Colles on Mars}} [[file:Tartarus Colles based on day THEMIS.png|thumb|Tartarus Colles based on [[Thermal Emission Imaging System|THEMIS]] day-time image]] '''Tartarus Colles''' are a group of knobby hills in the northern plains of [[Mars]].

==Context==

Tartarus Colles runs from 8° to 33° north latitude and 170° to 200° west longitude. They were named after a [[classical albedo features on Mars|classic albedo feature]]. The name was officially approved by the IAU in 1985.<ref>{{GPN|5874|Tartarus Colles}}</ref> The term "[[collis (planetary nomenclature)|Colles]]" is used for small hills or knobs.<ref>{{Cite web|url=https://planetarynames.wr.usgs.gov/DescriptorTerms|title = Planetary Names: Feature Types}}</ref>

There are over 40,000 knobs associated with Tartarus Colles.<ref name=hamilton2011 />

This landform is located within the [[Diacria quadrangle]] of [[Mars]].

==Geology==

Some researchers have proposed that the knobs of western Tartarus Colles are consistent with concurrent interpretations of knobs in [[Cerberus Palus]] (downstream of [[Athabasca Valles]]), which would suggest that they formed as the result of interactions between lava and water to form what has been termed by some authors as '''volcanic rootless constructs''' (VRC). This class of lava-water interactions includes [[rootless cone]]s, but have fewer genetic implications in their definition, as are not necessarily [[phreatomagmatic eruption|phreatomagmatic]] (resulting from the explosion of steam from the sudden evaporation of fluids on contact with lava). The water source is not required to have been added ''en masse'' in the form of some aqueous flood - instead possibly being available in the form of an extremely thin and shallow ground ice reservoir whose presence and extent is controlled by [[axial tilt|obliquity]] as an [[Milankovitch cycles|orbital forcer]].<ref name=hamilton2011 />

==Observational history==

In 2008, Mark A. Bishop of the [[Planetary Science Institute]] and the [[University of South Australia]] reported on his results using higher-order neighbor analysis to attempt to discern any kind of pattern in the distribution of Tartarus Colles' knobs. The purpose of the study was to reconcile competing hypotheses as to the origin of these knobby landforms, which had been analogized by other authors to putative [[pingo]]es and [[rootless cone]]s in [[Athabasca Valles]] and elsewhere in [[Elysium Planitia]]. Bishop found the cones of Tartarus Colles to exhibit a [[complete spatial randomness]] except where [[solifluction]] or magmatic effects were readily apparent.<ref name=bishop2008>{{cite journal |last1=Bishop |first1=M.A. |date=2008 |title=Higher-order neighbor analysis of the Tartarus Colles cone groups, Mars: The application of geographical indices to the understanding of cone pattern evolution |journal=Icarus |volume=197 |issue=1 |pages=73–83 |doi= 10.1016/j.icarus.2008.04.003|bibcode=2008Icar..197...73B }}</ref>

In 2011, Christopher W. Hamilton and Sarah A. Fagents of the [[University of Hawaiʻi at Mānoa]] in [[Honolulu]], [[Hawaii]], and Thorvaldur Thordarson of the [[University of Edinburgh]] in [[Scotland]] reported on the results of their geomorphic mapping, lava thickness estimations, and statistical analyses ([[Nearest neighbour distribution|nearest neighbor]] modeling) to investigate the hypotheses that the cones of Tartarus Colles are what the authors have termed "volcanic rootless constructs" - a more generalized variation of the term "[[rootless cone]]" that does not explicitly require a phreatomagmatic origin, or any clear explosive expression such as a pseudocrater. The authors criticize the tendency to generalize Martian pseudocrater analogies against [[Mývatn]], the Icelandic lake, which has been used as a type example of structures arising on Mars from water-lava interactions in a way that ignores the variability of such structures even across Iceland.<ref name=hamilton2011>{{cite journal |last1=Hamilton |first1=CW |last2=Fagents |first2=SA |last3=Thordarson |first3=T |date=2011 |title=Lava-ground ice interactions in Elysium Planitia, Mars: Geomorphological and geospatial analysis of the Tartarus Colles cone groups |journal=Journal of Geophysical Research |volume=116 |issue=E03004 |pages=E03004 |doi= 10.1029/2010JE003657|bibcode=2011JGRE..116.3004H |url=https://www.pure.ed.ac.uk/ws/files/11345598/LAVA.pdf |hdl=20.500.11820/bf40f0be-476a-42e6-8f89-78c16fc6805a |hdl-access=free }}</ref>

==Gallery==

Image:Tartarus Colles.JPG|Tartarus Colles as seen by [[Thermal Emission Imaging System|THEMIS]]. Click on image to see [[Dark Slope Streaks|dark slope streaks]]

Image:Tartarus Colles Channel.JPG|Tartarus Colles channel, as seen by [[HiRISE]]. Scale bar is 500 meters. Click on image to see bridge across channel. </gallery> {{commonscat|Tartarus Colles}}

==References== {{reflist}}

[[Category:Diacria quadrangle]] [[Category:Hills on Mars]]