title: Evidence for a basalt-free surface on Mercury and implications for internal heat.
abstract: Microwave and mid-infrared observations reveal that Mercury's surface contains less FeO + TiO2 and at least as much feldspar as the lunar highlands. The results are compatible with the high albedo (brightness) of Mercury's surface at visible wavelengths in suggesting a rock and soil composition that is devoid of basalt, the primary differentiate of terrestrial mantles. The occurrence of a basalt-free, highly differentiated crust is in accord with recent models of the planet's thermal evolution and suggests that Mercury has retained a hot interior as a result of a combination of inefficient mantle convection and minimal volcanic heat loss.
authors.affiliation: Department of Geology and Geophysics, University of California, Berkeley 94720, USA.
authors.forename: R
authors.initials: R
authors.lastname: Jeanloz
authors.forename: D L
authors.initials: DL
authors.lastname: Mitchell
authors.forename: A L
authors.initials: AL
authors.lastname: Sprague
authors.forename: I
authors.initials: I
authors.lastname: de Pater
mesh_terms: D005296:Ferrous Compounds / Q000032:analysis*; D006358:Hot Temperature; D018537:Mercury, Planet; D008903:Minerals / Q000032:analysis*; D017640:Silicates / Q000032:analysis*; D014025:Titanium / Q000032:analysis*
chemical_list: D005296:Ferrous Compounds; D008903:Minerals; D017640:Silicates; C060346:basalt; C009495:titanium dioxide; D014025:Titanium; C034236:ferrous oxide