August 28, 2011
Old Data, New Ideas
|With the cavalcade of new missions to the moon over the last few years it is natural that new books should follow. But before we get to them here is one of the last to be based on the previous generation of lunar explorations. Despite the cover with an LRO topography image, most of the articles in the new Geological Society of America publication use data from Lunar Orbiter and Clementine. However, these 7 articles show that there is still value in old data. One article whose results will continue to be cited for a long while is by Harald Hiesinger and colleagues who have nearly completed their age determinations for all lunar maria. Based on crater counts they find that most mare volcanism occurred between 3.8 and 3.3 b.y. ago, and it dribbled on to about 1.1 b.y. Herb Frey used pre-LOLA topo data to search for old degraded basins - this work is now being repeated with the much better LOLA altimetry. Stratigraphic studies of the Schrödinger and the South Pole-Aitken (SPA) basins, and comparisons of Schröters Valley with actual eruptions in Hawaii, provide new insights too. The most controversial paper comes from Pete Schultz and David Crawford who propose that an oblique impact formation of the SPA concentrated weaknesses roughly antipodally. This would account for the large system of concentric features that have, according to the authors, been misinterpreted as the ancient Procellarum Basin, and which also localized the maria in the northwest quadrant of the nearside. This quaifies as an audacious theory and presumably will be tested with new data.
Yesterday's LPOD: Why the Bend?
Tomorrow's LPOD: Is It Love or a Sinus Infection?