Other
Scientific paper
Oct 2010
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010dps....42.2904w&link_type=abstract
American Astronomical Society, DPS meeting #42, #29.04; Bulletin of the American Astronomical Society, Vol. 42, p.997
Other
Scientific paper
Difficulties encountered in reproducing Mercury's compositional attributes through modeling of formational processes have bolstered support for the hypothesis that one or more giant impacts stripped away a significant proportion of proto-Mercury's silicate mantle. Previous investigations demonstrate sufficient removal of mantle material to account for the planet's unusually high mean density, but do not consider the effects of multiple silicate and oxide phases. In this study we extend the present theory by investigating the consequences of a more realistic chemical model on the evolution of the ejected material. We suggest that the majority of condensation within the expanding vapor plume can be modeled as an equilibrium process following homogeneous nucleation of refractory phases leading to larger particle sizes than previously estimated. We use a thermodynamic model focused on major element composition of ejected material to analyze the effect of differential condensation on the expansion and final state of ejecta. For ejecta of sufficiently high specific entropy, our simplified chemical models indicate that energy released during condensation of MgO-rich phases buffers the temperature, delaying or preventing onset of FeO condensation. If sufficient spatial separation between condensates and vapor arises or if significant amounts of uncondensed FeO vapor remain uncondensed, reaccumulated ejecta would be enriched in MgO and refractory phases. This is compatible with an FeO depletion of Mercury's surface relative to other terrestrial bodies as spectroscopic data suggest (McClintock, Science, 2008). Despite conflicts in the data and the necessity for further relating it to bulk mantle composition, we describe potential tests of our model. Concentration of incompatible elements in the crust formed by a magma ocean would intensify FeO loss. The proposed process leads to a greater depletion in FeO and a lesser depletion in refractory, incompatible elements (Al2O3, CaO, TiO2), than models assuming uniform removal of material from a differentiated proto-Mercury.
Elkins-Tanton Linda
Stevenson Jacob D.
Wahl Sean
No associations
LandOfFree
Modification of Mercury's Bulk Mantle Composition by Reaccumulation of Condensed Ejecta from a Formative Giant Impact does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Modification of Mercury's Bulk Mantle Composition by Reaccumulation of Condensed Ejecta from a Formative Giant Impact, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Modification of Mercury's Bulk Mantle Composition by Reaccumulation of Condensed Ejecta from a Formative Giant Impact will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1122804