Unmixing of Phosphorus-Bearing Melts on Earth and Mars

• Applicant: Professorin Dr. Sharon Webb
• Subject Area: Mineralogy, Petrology and Geochemistry
• Term: from 2015 to 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 278990208

• Final Report Year: 2020

Final Report Abstract

This study investigated the effect of P2O5 on unmixing of melts, but also the effect of B2O3, F- and H2O was taken into account. The results of this study have brought new insight into the unmixing process in melts, but also lead to new questions. The working hypothesis at the moment is: Unmixing begins to occur with the first addition of P2O5; the unmixed melts are first seen in heat capacity data when the volume fraction reaches a critical value. The changes in viscosity observed upon the addition of P2O5 to the melt are due to the different structural positions of the P atoms in the melt and not primarily the effect of unmixing. Only in the case of the CHAMP melt would it appear that the viscosity remains constant with increasing P2O5 content and this effect may due to both the structural position of P and unmixing.

Publications

• Unmixing of Phosphorus bearing Melts on Earth and Mars. Dissertation Georg-August-Universität Göttingen 2019
  T.M. Busche