Mineral compositions for metamorphosed lower crustal xenoliths, central Montana, USA

These data are mineral compositions measured by electron microprobe, presented in the 2011 publication in Contributions to Mineralogy and Petrology by Blackburn et al., and in the 2012 publication in Geochemistry, Geophysics, and Geosystems by Mahan et al. The samples are from the Sweetgrass Hills and Homestead xenolith localities in central Montana, hosted by Eocene volcanics. The mineral chemistry was analyzed as part of an effort to help constrain the age, thermal evolution, metamorphic history, and physical properties (e.g., seismic velocities) of Montana deep crust. Geochronology data for some of these samples are also presented in the Contributions to Mineralogy and Petrology publication. Another related publication with similar data for additional samples is the 2012 Lithosphere article by Barnhart et al.