Consolmagno, G. J. Io: Thermal models and chemical evolution. Icarus 47: 36-45, 1981.

  1. Introduction

    Io and Moon similar size, similar density; much different present activity; therefore different composition & energy input

    principle thesis: "which starting conditions can evolve into Io as it is observed now?"

  2. Starting Conditions

    variables during condensation from nebula:

  3. Thermal History

    "what range of T and P have been reached inside Io?"

  4. Chemical History


moderately volatile-rich now; but started out at least as volatile-rich as C3 chondrite;
high nebular P, > 1 bar, condensation of FeS, FeO, Fe possible
long-lived radioactive and tidal heating to cause outgassing, convection, loss of CH4, CO2, H2O, freeing oxygen to yield FeO, Fe3O4, FexS from Fe and FeS;
deep interior must have been prevented from outgassing to allow FeO-FeS-Fe melting to form core, which is required because crust does not contain full complement of S