Mercury - the geology is hotter than expected

NASA held a teleconference for science reporters today to preview a set of papers coming out in tomorrow's issue of the journal Science, including one from planetary geologists at ASU.

The gist of the telecon and papers is that "the Analyses of data from the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft’s second flyby of Mercury in October 2008 show that the planet’s atmosphere, magnetosphere, and geological past are all characterized by much greater levels of activity than scientists first suspected."

On October 6, 2008, the probe flew by Mercury for the second time, capturing more than 1,200 high-resolution and color images of the planet unveiling another 30% of Mercury’s surface that had never before been seen by spacecraft.

Among the four panelists on today's telecon was Brett Denevi, a post-doc researcher at ASU, who is the lead author on a paper describing the evolution of Mercury’s crust. She's quoted on Wired.com as saying, "Up until before Messenger’s arrival, we weren’t even sure that volcanism existed on Mercury. Now we’re seeing it’s very widespread across the surface.”

"Many of these smooth plains are interpreted to be of volcanic origin, and they are globally distributed. Much of Mercury's crust may have formed through repeated volcanic eruptions in a manner more similar to the crust of Mars than to that of the moon."

[bottom right, a block diagram of the complex vertical and lateral heterogeneities of Mercury's crust. Much of the crust may have accumulated through volcanic eruptions of lavas of varying composition. Impact craters later exposed material from depth. These cross sections are simplified; more complicated patterns of vertical and horizontal mixing are expected as a result of intrusions of rising magma and impacts of various sizes throughout the crustal formation process. Not to scale. Text from NASA news release. Figure credit: NASA/Johns Hopkins University Applied Physics Laboratory/Arizona State University/Carnegie Institution of Washington]

Ref: The Evolution of Mercury’s Crust: A Global Perspective from MESSENGER
Science 1 May 2009: Vol. 324. no. 5927, pp. 613 - 618, DOI: 10.1126/science.1172226