Calcic amphibole thermobarometry in metamorphic and igneous rocks: New calibrations based on plagioclase/amphibole Al-Si partitioning and amphibole/liquid Mg partitioning

摘要

Dependencies of plagioclase/amphibole Al-Si partitioning, D-Al/si(plg/amp), ancramphibole/liquid Mg partitioning, D-Al/si(plg/amp), on temperature, pressure and phase compositions are investigated employing robust regression methods based on MM-estimators. A database with 92 amphibole-plagioclase pairs - temperature range: 650-1050 degrees C amphibole compositional limits: >0.02 apfu (230) Ti and >0.05 apfu Al - and 148 amphibole-glass pairs - temperature range: 800-1100 C; amphibole compositional limit: CaM4/(CaM4 + NaM4)> 0.75 - compiled from experiments in the literature was used for the calculations (amphibole normalization scheme: 13-CNK method).