The nature and origin of Mafic Mound in the South Pole‐Aitken Basin. Issue 19 (15th October 2015)

• Record Type: Journal Article
• Authors: Moriarty, Daniel P.; Pieters, Carle M.
• Is Part Of: Geophysical research letters. Volume 42:Issue 19(2015:Oct.)
• Page Start: 7907
• Page End: 7915
• Publication Date: 2015-10-15
• Subjects: South Poke‐Aitken Basin -- impact basins -- Moon Mineralogy Mapper -- Mafic Mound -- impact melt -- lunar volcanic constructs; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/2015GL065718
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: "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. Key Points: Mafic Mound in central SPA is 75 km across, 1 km high, and rich in high‐Ca pyroxene New observations (composition, topography, and gravity) strongly suggest an extrusive magmatic origin The proposed magma source is related to the formation and evolution of SPA