Abstract

The distribution of Li and its two stable isotopes among mantle minerals has been widely used in the past to decipher the physical and chemical state of the Earth’s interior through geological time-scales. Hence in this study, using a combination of Density Functional Theory (DFT) and Density Functional Perturbation Theory (DFPT) we study the mechanism of incorporation and distribution of Li ion and its two isotopes (6Li and 7Li) in the olivine (M2SiO4, M:Mg,Fe) lattice as a function of temperature and Fe concentration. Li is known to occupy both interstitial and substitutional sites in olivine (Dohmen 2010, GCA). Our calculations indicate that Li, Fe2+ and Fe3+ prefer to occupy the smaller and less distorted M1 site. A positive correlation between Fa-content and Li concentration is suggested. Calculation of isotopic fractionation of Li between the interstitial and substitutional sites of forsterite shows that the heavier isotope gets populated in the interstitial sites of olivine. Incorporation of Fe is found to enhance the extent of fractionation. Our study hence emphasizes the importance of considering the influence of Fe, even if it is present in small concentrations, while determining the isotopic fractionation of minor and trace elements in mantle minerals. We also offer valuable insights into the microscopic origin of the role played by Fe in modulating the isotopic fractionation of Li in mantle minerals.

Full Text
Paper version not known

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.