Lunar Reconnaissance Orbiter press briefing: silicic volcanoes on the Moon
Posted by Emily Lakdawalla
16-09-2010 13:56 CDT
I'm listening to a press briefing from several members of the Lunar Reconnaissance Orbiter science team, regarding three papers published today in Science:
- "Global Distribution of Large Lunar Craters: Implications for Resurfacing and Impactor Populations," by James W. Head and coauthors on the Lunar Orbiter Laser Altimeter team;
- "Global Silicate Mineralogy of the Moon from the Diviner Lunar Radiometer," by Bejnamin Greenhagen and coauthors on the Diviner team; and
- "Highly Silicic Compositions on the Moon," by Timothy Glotch and coauthors on the Diviner team.
Here's a couple of the comments that Tim made today, paraphrased: The high-silica materials are fundamentally different from basaltic maria and anorthositic highlands. They have high SiO2. We see them in volcanoes and inside craters. He showed an image of Hansteen Alpha, which I reproduce below, and said that if it were on Earth we'd call it a rhyolitic volcano. It's like the dome formed on Mt. St. Helens after its eruption. He also showed an image of the crater Aristarchus, and pointed out orange and red colors associated with crater's central peak and ejecta blanket. This suggests to a geologist, he said, that the material was brought up by the impact. As for what the silicic materials mean, they have several ideas, but they note that they're mostly found within an area known to lunar mineralogists as the Procellarum KREEP terrain, which is an area unusually enriched in radiactive elements. "So what we think happened is that the basaltic magma intruded into the anorthositic crust. The heat diffused into the crust and started to melt it. The highly silicic component either reached the surface and erupted or separated and formed granitic bodies. In either case, we have new, really juicy targets for lunar exploration, and the Moon is a lot more complicated than we thought."
I won't go into much more detail on this because I actually wrote about one of these pieces of research a lot when it was presented at the Lunar and Planetary Science Conference in March.Probably just as significant as these science results is an event that took place on Lunar Reconnaissance Orbiter today. The mission was actually developed to map out lunar terrain for possible human landing sites, and as such it was under the management of NASA's Exploration Systems Mission Directorate, or ESMD, the human exploration side of NASA. With its stationkeeping rocket burn this morning, Lunar Reconnaissance Orbiter was officially handed over from ESMD to the Science Mission Directorate or SMD, for a two-year science mission, in a transition that was planned long before the cancellation of the Constellation program. Rich Vondrak, Lunar Reconnaissance Orbiter's project scientist, said that there are five main science goals for the extended mission, the most important tow of which are to understand the Moon's bombardment history and to understand its detailed surface composition. As such, he said, these three publications give them a "running start" on their science mission.
The last press question today -- there weren't many -- was about the accessibility of the data to the public. Benjamin Greenhagen spoke up to point out that all the Diviner data, including what was presented today, are available from the Diviner website.
Finally, this wasn't part of the press briefing, but it was a nice new photo of Earth from the Moon released on the Lunar Reconnaissance Orbiter website today.
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