February 11, 2013
More Evidence
images from Ashley et al, 2013, LPSC #2504.
Forty years ago lunar red spots were discovered. These are small volcanic features, like the Gruithuisen domes,
that absorb in the ultraviolet and hence look bright at the red end of the spectrum. Some are cones, a few are
steep domes and others are just odd pieces of old terrain. Their steep sides and conical shapes have been sug-
gested as evidence that they were made of materials more viscous than normal mare lavas. Scientists working
with LRO data have brought to light new information about the Lassell Massif, a red spot just east of 9 km wide
Lassell C. It is a hilly ridge of older material surrounded by younger lavas of Mare Nubium. The LRO mosaic
depicts the area, the chart labeled "a" shows the topography of half of Lassell C and the Massif, and "b" presents
an interpretive geologic map. Lassell G & K are suggested to perhaps be volcanic pits or explosion craters. The
image at the far right was constructed from LRO's Diviner infra-red data with the purple-blue representing material
that is silica-rich. This is strong support for the idea that this red spot does represent eruptions of magmas more
evolved than mare lavas.
Chuck Wood
Related Links
Rükl plate 54
21st Century Atlas chart 16.
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