Contributions to Mineralogy and Petrology

, Volume 66, Issue 2, pp 113–117 | Cite as

Experimental calibration of the partitioning of Fe and Mg between biotite and garnet

  • J. M. Ferry
  • F. S. Spear
Article

Abstract

The cation exchange reaction Fe3Al2Si3O12 +KMg3AlSi3O10(OH)2 = Mg3Al2Si3O12+KFe3-AlSi3 O10(OH)2 has been investigated by determining the partitioning of Fe and Mg between synthetic garnet, (Fe, Mg)3Al2Si3O12, and synthetic biotite, K(Fe, Mg)3AlSi3O10(OH)2. Experimental results at 2.07 kbar and 550 °–800 ° C are consistent with In [(Mg/Fe) garnet/(Mg/Fe) biotite] = -2109/T(°K) +0.782. The preferred estimates for Δ¯H and Δ¯S of the exchange reaction are 12,454 cal and 4.662 e.u., respectively. Mixtures of garnet and biotite in which the ratio garnet/biotite=49/1 were used in the cation exchange experiments. Consequently the composition of garnet-biotite pairs could approach equilibrium values in the experiments with minimal change in garnet composition (few tenths of a mole percent). Equilibrium was demonstrated at each temperature by reversal of the exchange reaction. Numerical analysis of the experimental data yields a geothermometer for rocks containing biotite and garnet that are close to binary Fe-Mg compounds.

Keywords

Experimental Data Exchange Reaction Mineral Resource Cation Exchange Minimal Change 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag 1978

Authors and Affiliations

  • J. M. Ferry
    • 1
  • F. S. Spear
    • 1
  1. 1.Geophysical LaboratoryWashington, D.C.USA

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