The Mairan domes: Silicic volcanic constructs on the Moon

Abstract

The Mairan domes are four features located in northern Oceanus Procellarum at ∼312.3E, 41.4N on the Moon. High resolution visible imagery, visible‐to‐mid‐IR spectra, and Lunar Prospector Th abundance data all indicate that these four domes have a composition that is consistent with derivation from a Si‐rich, highly evolved magma.

The Lassell massif—A silicic lunar volcano

“…Magmas enriched in incompatible elements (e.g., Th) typically require multiple processing episodes to form, but the observed distribution and compositional range of lunar silicic materials are difficult to explain with current models of lunar magma fractionation (e.g., Hawke et al, 20 03;Hagerty et al, 20 06;Jolliff et al, 2011Jolliff et al, , 2012Kusuma et al, 2012 ). Nevertheless, both telescopic and orbital observations of morphologically and compositionally distinct constructs, including the nearside lunar red spots (regions of strong ultraviolet (UV) absorption), have supported non-mare, Si-rich volcanic interpretations (e.g., Whitaker, 1972a;Malin, 1974;Wood and Head, 1975;Head and McCord, 1978;Müller et al, 1986;Chevrel et al, 1999;Hawke et al, 2001Hawke et al, , 2003Hagerty et al, 2006;Glotch et al, 2010;Wagner et al, 2010;Glotch et al, 2011;Jolliff et al, 2011;Kusuma et al, 2012;Lawrence et al, 2014;Wilson et al, 2015 ).…”

Radar Albedo Feature

“…Remote sensing studies of several lunar domes show that they have high SiO 2 , low FeO, and high Th abundances (e.g., Wilson and Head 2003;Hagerty et al 2006;Glotch et al 2010Glotch et al , 2011, consistent with the compositions of silicic lithologies found in the lunar sample suite (e.g., Papike et al 1998). The most recent results from the Diviner Lunar Radiometer Experiment on the LRO have confirmed the presence of highly silicic volcanic domes on the Moon, thus supporting the strong correlation between silica-rich lithologies and elevated Th abundances (e.g., Hagerty et al 2006;Glotch et al 2010Glotch et al , 2011.…”

“…The most recent results from the Diviner Lunar Radiometer Experiment on the LRO have confirmed the presence of highly silicic volcanic domes on the Moon, thus supporting the strong correlation between silica-rich lithologies and elevated Th abundances (e.g., Hagerty et al 2006;Glotch et al 2010Glotch et al , 2011.…”

“…In many instances, red spots are embayed by younger mare, suggesting that they were derived from local material and may have originally covered a greater portion of the lunar surface (Bruno et al 1991;Hawke et al 2003). Some red spots have compositional and morphologic characteristics that are consistent with silicic, nonmare, volcanic constructs (Head and McCord 1978;Bruno et al 1991;Chevrel et al 1999;Hawke et al 2001Hawke et al , 2003Wagner et al 2002;Wilson and Head 2003;Hagerty et al 2006;Glotch et al 2010Glotch et al , 2011. Several of the red spots are different from typical highland topography in that the domes contain summit craters, sinuous scarps, and downslope-oriented ridges and furrows.…”

“…Malin (1974) and Wood and Head (1975) presented evidence that many red spots were produced by nonmare volcanism and suggested a connection with KREEP basalts. Subsequent studies have shown that some red spots do in fact have compositional and morphologic characteristics that are consistent with silicic, nonmare, volcanic constructs (Head and McCord 1978;Bruno et al 1991;Chevrel et al 1999;Hawke et al 2001Hawke et al , 2003Wagner et al 2002;Wilson and Head 2003;Hagerty et al 2006;Glotch et al 2010Glotch et al , 2011. Definition A large area marked by reflectivity or color distinctions from adjacent areas or a broad geographic region (IAU Gazetteer 2014).…”