The importance of deep reactions between ascending komatiite and pre-existing protocratonic lithosphere for the chemistry of Archaean peridotites and greenstone belt volcanics: insights from reaction experiments

We performed a series of layered reaction experiments between komatiite and harzburgite at 3 GPa and 1400–1700 °C to simulate the interaction of ascending komatiitic melts with the depleted protocratonic lithosphere. In addition, thermodynamic modelling was carried out using THERMOCALC over a range of pressure–temperature conditions and bulk compositions. File S1. Modal abundance variations as a function of temperature, comparison between experimental and thermodynamic modelling results, and P–T pseudosections for the harzburgite (HZ), komatiite (KM-01), and komatiite–harzburgite hybrid (RMZ) systems. File S2. Major- and minor-element compositions of olivine, orthopyroxene, garnet, clinopyroxene, and melt from the reaction and partial melting experiments. File S3. Thermodynamic modelling of the reacted orthopyroxene-rich and olivine-rich layers. File S4. Complete thermodynamic modelling results.