Mercury/Mantle

Mantle about 500-700 km thick consisting of Silicates surrounding Mercury's core and beneath its crust. It is thought to not rise and fall in convective patterns like Earth and other larger planets, and so may not have cooled as quickly, enabling volcanism to persist over halfway through its lifespan.

Web Pages

 * http://en.wikipedia.org/wiki/Mercury_%28planet%29#Internal_structure

Evidence of Younger Volcanic Activity

 * See Mercury/Volcanoes, Rachmaninoff Basin


 * http://www.nasa.gov/home/hqnews/2010/jul/10-170_Messenger_New_Info.html
 * http://www.nytimes.com/2010/07/20/science/20mercury.html?_r=2&ref=science
 * http://www.wired.com/wiredscience/2010/07/mercury-flyby-teaser/
 * http://www.space.com/scienceastronomy/mercury-has-magnetic-storms-volcano-evidence-100715.html