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The nature and origin of Mafic Mound in the South Pole‐Aitken Basin
Author(s) -
Moriarty Daniel P.,
Pieters Carle M.
Publication year - 2015
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 - 10.1002/2015gl065718
Subject(s) - mafic , geology , geochemistry , impact crater , volcano , basalt , pyroxene , volcanism , petrology , olivine , paleontology , tectonics , physics , astrobiology
“Mafic Mound” is a distinctive and enigmatic feature 75 km across and 1 km high near the center of the vast South Pole‐Aitken Basin (SPA). Using several modern data sets, we characterize the composition, morphology, and gravity signature of the structure in order to assess its origin. Mafic Mound is found to exhibit a perched circular depression and a homogeneous high‐Ca pyroxene‐bearing composition. Several formation hypotheses based on known lunar processes are evaluated, including the possibilities that Mafic Mound represents (1) uplifted mantle, (2) SPA‐derived impact melt, (3) a basalt‐filled impact crater, or (4) a volcanic construct. Individually, these common processes cannot fully reproduce the properties of Mafic Mound. Instead, we propose a hybrid origin in which Mafic Mound is an edifice formed by magmatic processes induced by the formation and evolution of SPA. This form of nonmare volcanism has not previously been documented on the Moon.