Lunar dome

Typical lunar dome Milichius Pi, about 11 km across

Alunar domeis a type ofshield volcanothat is found on the surface of theEarth'sMoon.They are typically formed by highly viscous, possiblysilica-richlava,erupting from localized vents followed by relatively slow cooling. Lunar domes are wide, rounded, circular features with a gentle slope rising in elevation a few hundred meters to the midpoint. They are typically 8–12 km in diameter, but can be up to 20 km across. Some of the domes contain a small craterlet at the peak.

Some of the domes have been shown to consist of the same materials as thelunar maria.Thus they could be created by some mechanism that differs from the mare-forming flows. It is thought that these domes are formed from a smallermagma chamberthat is closer to the surface than is the case for a mare. This results in a lower pressure, and so the lava flows more slowly. Themagmawells up through a crack in the surface, but the flow eventually concentrates through one primary vent. This concentration can then result in a vent crater at the peak of the dome.

The cluster of lunar domes at theMarius Hillswas considered as a possible landing site ofApollo 15.There are concentrations of lunar domes near the cratersHortensius,andT. Mayer,across the top ofMons Rümker,and inMare Fecunditatis.Solitary lunar domes are also found, includingKies Pi(π),Milichius Pi(π),Mons Gruithuisen Gamma(γ) and Delta (δ), and domes near the cratersGambart C,Beer,andCapuanus.Omega Cauchy (ω) and Tau Cauchy (τ) form a pair of domes near the craterCauchy.Likewise nearAragoare the domes Arago Alpha (α) and Arago Beta (β). There are two domes south ofMons Esam. TheIAUdoes not currently have rules that establish the naming of lunar domes, but the practice in the professional literature and in lunar sciences is to name the dome with the name of the nearest crater followed by a number that denotes the order of discovery.

Examples

• 
  Omega Cauchy, with the small craterDonnaat its summit,Mare Tranquillitatis
• 
  Oblique view of a dome north ofSinas,Mare Tranquillitatis
• 
  Oblique view of lunar dome nearMessierinMare Fecunditatis.Note dark 'halo' deposits. The crater left of center is unrelated (formed after the dome).
• 
  Lunar dome south ofBeer,Mare Imbrium
• 
  Oblique view of three of the six lunar domes north ofHortensius,fromLunar Orbiter 3
• 
  LROimage of the Hortensius domes
• 
  Domes inLacus Veris,Orientale basin
• 
  Mons Gruithuisen Gamma (left) and Delta (right), fromLunar Orbiter 4

See also

• Volcanism on the Moon

References

• Lionel Wilson and James W. Head, "Lunar Gruithuisen and Mairan domes: Rheology and mode of emplacementArchived2007-03-12 at theWayback Machine",Journal of Geophysical Research,vol. 108, 2003.
• Lena, R., Wöhler, C., Phillips, J., Chiocchetta, M.T., "Lunar Domes:Properties and Formation Processes", "Springer Praxis Books", 2013, "[1]".

External links

• Marvin W. Huddleston, ALPO Lunar Dome Survey Coordinator's web page on Lunar Domes
• Association of Lunar & Planetary Observers, Lunar Section
• GLR Group Website
• UAI Lunar Dome Introduction