Activity-composition relations for the calculation of partial melting equilibria in metabasic rocks

作者：Green, E. C. R.^*; White, R. W.; Diener, J. F. A.; Powell, R.; Holland, T. J. B.; Palin, R. M.

来源：Journal of Metamorphic Geology, 2016, 34(9): 845-869.

DOI：10.1111/jmg.12211

• amphibolite
• calibration
• granulite
• Holland & Powell dataset
• pseudosection

A set of thermodynamic models is presented that, for the first time, allows partial melting equilibria to be calculated for metabasic rocks. The models consist of new activity-composition relations combined with end-member thermodynamic properties from the Holland & Powell dataset, version 6. They allow for forward modelling in the system Na2O-CaO-K2O-FeO-MgO-Al2O3-SiO2-H2O-TiO2- Fe2O3. In particular, new activity-composition relations are presented for silicate melt of broadly trondhjemitic-tonalitic composition, and for augitic clinopyroxene with Si-Al mixing on the tetrahedral sites, while existing activity-composition relations for hornblende are extended to include K2O and TiO2. Calibration of the activity-composition relations was carried out with the aim of reproducing major experimental phase-in/phase-out boundaries that define the amphibolite-granulite transition, across a range of bulk compositions, at <= 13 kbar.

• 出版日期2016-12