Jump to content

Rootless cone

From Wikipedia, the free encyclopedia
A rootless cone atMyvatnLake, Iceland.

Arootless cone,also formerly called apseudocrater,[1]is avolcaniclandformwhich resembles a truevolcanic crater,but differs in that it is not an actual vent from whichlavahas erupted. They are characterised by the absence of anymagmaconduit which connects below the surface of a planet.

Rootless cones are formed bysteam explosionsas flowing hot lava crosses over a wet surface, such as aswamp,alake,or a pond. The explosive gases break through the lava surface in a manner similar to aphreatic eruption,and thetephrabuilds up crater-like forms which can appear very similar to real volcanic craters.

Well known examples are found inIcelandsuch as the craters in the lakeMývatn(Skútustaðagígar), theRauðhólarin the region of the capital cityReykjavíkor theLandbrotshólarof South-Iceland's Katla UNESCO Global Geopark nearKirkjubæjarklaustur.Rootless cones have also been discovered in theAthabasca Vallesregion ofMars,wherelavaflowssuperheatedgroundwaterin the underlying rocks.[2]

Volcanologistswitnessed the formation of a rootless cone for the first time in history during a steam explosion in connection with thefirst eruption of Eyjafjallajökullin March 2010.[3]

Images[edit]

  • "Rootless Cones" on Mars - due to lava flows interacting with water (MRO, January 4, 2013) (21°57′54″N 197°48′25″E / 21.965°N 197.807°E / 21.965; 197.807).
    "Rootless Cones" onMars- due tolava flowsinteracting withwater(MRO,January 4, 2013) (21°57′54″N197°48′25″E/ 21.965°N 197.807°E/21.965; 197.807).
  • "Rootless Cones" on Mars (MRO, January 4, 2008) (25°54′36″N 173°45′36″E / 25.910°N 173.760°E / 25.910; 173.760)
    "Rootless Cones" onMars(MRO,January 4, 2008) (25°54′36″N173°45′36″E/ 25.910°N 173.760°E/25.910; 173.760)
  • Rootless Cones, as seen by HiRISE under HiWish program. These group of rings or cones are believed to be caused by lava flowing over water ice or ground containing water ice.[4] [5] The ice quickly changes to steam which blows out a ring or cone.
    Rootless Cones, as seen by HiRISE under HiWish program. These group of rings or cones are believed to be caused by lava flowing over water ice or ground containing water ice.[4][5]The ice quickly changes to steam which blows out a ring or cone.
  • Rootless Cones, as seen by HiRISE under HiWish program. These group of rings or cones are believed to be caused by lava flowing over water ice or ground containing water ice. The ice quickly changes to steam which blows out a ring or cone. Here the kink in the chain may have been caused by the lava changing direction.
    Rootless Cones, as seen by HiRISE under HiWish program. These group of rings or cones are believed to be caused by lava flowing over water ice or ground containing water ice. The ice quickly changes to steam which blows out a ring or cone. Here the kink in the chain may have been caused by the lava changing direction.
  • Rootless Cones, as seen by HiRISE under HiWish program. These group of rings or cones are believed to be caused by lava flowing over water ice or ground containing water ice. The ice quickly changes to steam which blows out a ring or cone. Here the kink in the chain may have been caused by the lava changing direction. Some of the forms do not have the shape of rings or cones because maybe the lava moved too quickly; thereby not allowing a complete cone shape to form.
    Rootless Cones, as seen by HiRISE under HiWish program. These group of rings or cones are believed to be caused by lava flowing over water ice or ground containing water ice. The ice quickly changes to steam which blows out a ring or cone. Here the kink in the chain may have been caused by the lava changing direction. Some of the forms do not have the shape of rings or cones because maybe the lava moved too quickly; thereby not allowing a complete cone shape to form.
  • Wide view of field of rootless cones, as seen by HiRISE under HiWish program
    Wide view of field of rootless cones, as seen by HiRISE under HiWish program
  • Close view of rootless cones with tails that suggest lava was moving toward the Southwest over ice-rich ground, as seen by HiRISE under HiWish program
    Close view of rootless cones with tails that suggest lava was moving toward the Southwest over ice-rich ground, as seen by HiRISE under HiWish program
  • Close view of cones with the size of a football field shown, as seen by HiRISE under HiWish program
    Close view of cones with the size of a football field shown, as seen by HiRISE under HiWish program

See also[edit]

Wikimedia Commons has media related toRootless cones.

References[edit]

  1. ^Burr, Devon M.; Bruno, Barbara C.; Lanagan, Peter D.; Glaze, Lori S.; Jaeger, Windy L.; Soare, Richard J.; Wan Bun Tseung, Jean-Michel; Skinner, James A.; Baloga, Stephen M. (2009). "Mesoscale raised rim depressions (MRRDs) on Earth: A review of the characteristics, processes, and spatial distributions of analogs for Mars".Planetary and Space Science.57(5–6): 579–596.Bibcode:2009P&SS...57..579B.doi:10.1016/j.pss.2008.11.011.
  2. ^Jaeger, W. L. et al. (2008)Morphologic Characteristics and Global Distribution of Phreato-volcanic Constructs on Mars as seen by HiRISE,Lunar and Planetary Science XXXIX[1]PDF. Retrieved 2010-07-11.
  3. ^Kvöldfréttir Stöðvar Tvö "Viðtal við Ármann Höskuldsson eldfjallafræðing"Fréttastofa Stöðvar Tvö
  4. ^Czechowski, Leszek; Zalewska, Natalia; Zambrowska, Anita; Ciazela, Marta; Witek, Piotr; Kotlarz, Jan (2023)."The formation of cone chains in the Chryse Planitia region on Mars and the thermodynamic aspects of this process".Icarus.396.Bibcode:2023Icar..39615473C.doi:10.1016/j.icarus.2023.115473.S2CID256787389.
  5. ^Czechowski, L., et al. 2023. The formation of cone chains in the Chryse Planitia region on Mars and the thermodynamic aspects of this process. Icarus: Volume 396, 15 May 2023, 115473

External links[edit]

Retrieved from "https://en.wikipedia.org/w/index.php?title=Rootless_cone&oldid=1212769847"