January 28, 2011
images from Spudis, McGovern and Kieffer, LPSC 2011
Some years ago I proposed that a large domical structure near Gardner be called a megadome. Now Paul Spudis, Patrick McGovern and Walter Kiefer of the Lunar and Planetary Institute in Houston have proposed the existence of even larger domes that contain well known smaller volcanics. The circles on the LRO LOLA topo image identify the extent of swells they consider to be large shield volcanoes, similar to ones on Mars, Venus and Earth. The T. Mayer - Hortensius swell (middle image) is 300 km wide and 2 km high. The classic map of the same area on the right shows the familiar Hortensius dome cluster and others near T. Mayer as red circles with central dots. While this putative shield, and the Cauchy one, and a smaller one centered on the unrelated Kepler impact crater are previously unsuspected, the shield-like structure of the Marius Hills, Aristarchus Plateau, Harbinger region and Rumker are long known. The authors point out that, unlike many shields on other planets, these proposed lunar ones lack summit calderas, radial fissures and flows - does that weaken the interpretation? The confirmation of these large scale features that seem to have controlled the locations of smaller scale volcanics is well within the abilities of LPOD readers. Do topographic transects agree that these swells exist? Are there others? Tomorrow we will discuss new arguments to explain the posiitoning of these proposed large shields.
Hooray! On Thursday the abstracts for the upcoming Lunar and Planetary Science Conference appeared, and this paper is just one of hundreds that are now available to read.
Rükl plate 30
Yesterday's LPOD: Micro Features
Tomorrow's LPOD: A Moonless Night