F, Cl, and H2O in nominally anhydrous minerals and hydrous minerals from lithospheric mantle xenoliths

These datasets include nominally anhydrous mineral (NAM; clinopyroxene, orthopyroxene, and olivine) major and minor element compositions, as well as F, Cl, and H2O concentrations in NAMs and F and Cl concentrations in hydrous minerals. Samples analyzed are peridotite xenoliths of the North American sub-continental lithospheric mantle (SCLM) from the Navajo Volcanic Field (NVF) and Cerro Chato on the Colorado Plateau and Elephant Butte and Kilbourne Hole along the southern Rio Grande Rift, as well as one peridotite xenolith from O'ahu, Hawaii. Previous studies have suggested that the North American SCLM has been metasomatized by fluids derived from the subducted Farallon plate. In the modally hydrated NVF xenoliths, hydrous minerals contain the vast majority of water and halogens. Pyroxenes in these xenoliths are F-poor but variably enriched in H2O and Cl, suggesting metasomatism via a hydrous fluid. Additionally, samples with anomalously high water contents have variations in Cl content across the grains that resemble diffusion profiles but do not have such variations in H2O or F. This suggests recent volatile enrichment leading to Cl heterogeneity in a subset of samples.

In the modally anhydrous xenoliths, F is enriched in the NAMs and correlates with indices of melt depletion, whereas Cl is depleted and does not correlate with indices of melt depletion or metasomatism.