Abstract
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.
| Original language | English |
|---|---|
| Pages (from-to) | 845-869 |
| Number of pages | 25 |
| Journal | Journal of Metamorphic Geology |
| Volume | 34 |
| Issue number | 9 |
| Early online date | 31 Aug 2016 |
| DOIs | |
| Publication status | Published - 6 Nov 2016 |
Keywords
- Amphibolite
- Calibration
- Granulite
- Holland & Powell dataset
- Pseudosection