Olivine xenocrysts reveal carbonated mid-lithosphere in the northern Slave craton

• Published in: Lithos 2022-04, Vol.414-415, p.106633, Article 106633
• Main Authors: Veglio, Christian, Lawley, Christopher J.M., Pearson, D. Graham, Kjarsgaard, Bruce A., Petts, Duane C., Jackson, Simon E.
• Format: Article
• Language: English
• Subjects: Jericho; Mantle; Olivine; Slave; Xenocryst; Xenolith
• ISSN: 0024-4937; 1872-6143
• DOI: 10.1016/j.lithos.2022.106633

The cold, rigid, and melt-depleted mantle underlying Archean cratons plays an important role in the preservation of the overlying continental crust and is one of the main sources of diamonds. However, with the possible exception of rare earth elements (REE) and platinum group-elements (PGE), the concentrations and host mineral phases for many other critical trace elements within lithospheric mantle remain very poorly understood. Here we address that knowledge gap, presenting new electron microprobe and laser-ablation inductively-coupled-plasma mass-spectrometry results for a suite of mantle xenoliths (n = 12) and olivine xenocrysts (n = 376) from the Jericho, Muskox, and Voyageur kimberlites (northern Slave craton, Canada). Low-temperature (1000 °C) garnet and clinopyroxene crystals with Ti/Eu ratios > > 1000, and olivine xenocrysts suggest that interaction with ultramafic silicate melts is the most likely mechanism to re-fertilize melt-depleted peridotite with incompatible elements toward the base of the lithosphere (~200 km). In contrast, lower temperature garnet and clinopyroxene with Ti/Eu ratios