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Newly Discovered Ring‐Moat Dome Structures in the Lunar Maria: Possible Origins and Implications
Author(s) -
Zhang Feng,
Head James W.,
Basilevsky Alexander T.,
Bugiolacchi Roberto,
Komatsu Goro,
Wilson Lionel,
Fa Wenzhe,
Zhu MengHua
Publication year - 2017
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2017gl074416
Subject(s) - lava , geology , lava dome , dome (geology) , volcano , crust , dike , volcanism , magma , petrology , lunar mare , geophysics , geochemistry , geomorphology , seismology , basalt , tectonics
Abstract We report on a newly discovered morphological feature on the lunar surface, here named Ring‐Moat Dome Structure (RMDS). These low domes (a few meters to ~20 m height with slopes <5°) are typically surrounded by narrow annular depressions or moats. We mapped about 2,600 RMDSs in the lunar maria with diameters ranging from tens to hundreds of meters. Four candidate hypotheses for their origin involving volcanism are considered. We currently favor a mechanism for the formation of the RMDS related to modification of the initial lava flows through inflated flow squeeze‐ups and/or extrusion of magmatic foams below a cooling lava flow surface. These newly discovered features provide new insights into the nature of emplacement of lunar lava flows, suggesting that in the waning stages of a dike emplacement event, magmatic foams can be produced, extrude to the surface as the dike closes, and break through the upper lava flow thermal boundary layer (crust) to form foam mounds and surrounding moats.