Peridotite and pyroxenite xenoliths from the Muskox kimberlite, northern Slave craton, Canada ...

• Main Author: Newton, David Edward
• Format: Text
• Language: English
• Published: University of British Columbia 2015
• Subjects: muskox
• Online Access: https://dx.doi.org/10.14288/1.0166626; https://doi.library.ubc.ca/10.14288/1.0166626

Petrography, mineralogy and thermobarometry are reported for 53 mantle-derived xenoliths from the Muskox kimberlite pipe in the northern Slave craton. The xenolith suite includes 15% coarse spinel peridotite, 4% coarse spinel-garnet peridotite, 4% coarse garnet peridotite, 9% porphyroclastic peridotite, 60% websterite and 8% orthopyroxenite. Peridotites are composed primarily of forsteritic olivine (Fo 89-94), enstatite (En 89-94), Cr-diopside, Cr-pyrope garnet and chromite spinel. Pyroxenites are composed primarily of enstatite (En 90-92), Cr-diopside and Cr-pyrope garnet. Thermobarometric estimates were made using two-pyroxene, garnet-clinopyroxene and Ca-in-orthopyroxene thermometers and garnet-orthopyroxene barometer. Results suggest that coarse peridotites equilibrated at 650-1220 °C and 23-63 kbar; porphyroclastic peridotites equilibrated at 1200-1350 °C and 57-70 kbar; pyroxenites equilibrated at 1030-1230 °C and 50-63 kbar. Muskox xenoliths are compared with xenoliths recovered from the neighboring ...