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Stable Ni isotope heterogeneity in the terrestrial mantle

Thursday 17 September - 4 PM

Dr. Naomi Saunders

Lamont-Doherty Earth Observatory, Columbia University, USA

ABSTRACT: Bulk peridotite xenoliths show surprisingly significant heterogeneity in Ni isotopic composition, with pyroxenite xenoliths increasing the observed range significantly. Xenolith data has provided evidence that the heterogeneity observed in Ni isotopes cannot be reproduced by melting processes, mineral fractionation, or minor metasomatism. Evidence instead supports that heterogeneity in Ni isotopic composition is related to mantle fertility and enrichment, suggesting that Ni isotopes can be used to trace recycled input into the mantle, regardless of time or amount of melting/crystallisation since input.

 

BIO: Naomi Saunders grew up in NW England before doing her Earth Sciences undergrad and Geochemistry PhD at the University of Oxford (completed, Dec 2019). She is now working as a post doc for Prof Sir Alex Halliday at Lamont-Doherty Earth Observatory, part of Columbia University in New York. Her work has focussed on developing the method for purification and analysis of Ni isotopic compositions, and investigating resulting data to investigate the cause of Ni isotope fractionation in high temperature terrestrial and lunar environments and the uses of Ni isotopic compositions in answering geochemical questions about the terrestrial mantle. New research projects relating to Ni isotopes are on the horizon with the end of most lockdown precautions.