Three new iron-phosphate minerals from the El Ali iron meteorite, Somalia: Elaliite, Fe²⁺₈Fe³⁺ (PO₄)O₈; elkinstantonite, Fe₄(PO₄)₂O; and olsenite, KFe₄(PO₄)₃
Abstract
Petrologic investigation of the El Ali IAB iron meteorite (Somalia) revealed three new minerals: elaliite (Fe2+8Fe3+ (PO4)O8, IMA 2022-087), elkinstantonite(Fe4(PO4)2O, IMA 2022-088), and olsenite (KFe4(PO4)3, IMA 2022-100). The name elaliite recognizes the occurrence of this mineral within the El Ali meteorite, originally located at 4° 17′ 17″N, 44° 53′ 54″E. Elkinstantonite is named after Linda (Lindy) Elkins-Tanton (b. 1965), a planetary scientist and professor in the School of Earth and Space Exploration at Arizona State University. The name olsenite is in honor of Edward J. Olsen (1927-2020), the former Curator of Mineralogy and Meteorites at the Field Museum of Natural History in Chicago (1960-1991). The new minerals and their names have been approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association. The holotype specimens of elaliite, elkinstantonite and olsenite consist of the polished block mount with accession number MET11814/2-1/EP1 deposited in the University of Alberta Meteorite Collection. Elaliite, elkinstantonite and olsenite occur along with wustite, troilite, sarcopside and Ca-bearing graftonite within inclusions in the iron-nickel metal (kamacite, 9.4 wt% Ni) that makes up the bulk of the El Ali sample. The empirical formulas determined by electron probe microanalysis for elaliite, elkinstantonite, and olsenite are: (Fe2+7.943Fe3+1.020Cr0.010Ni0.006Ca0.004Mn0.004)Σ8.987(P0.932Si0.077S0.005)Σ1.014O12, (Fe2+3.947Mn0.016Ni0.003Ca0.001Cr0.001)Σ3.968(P1.986Si0.014S0.013)Σ2.013O9, and (K0.820Na0.135Ca0.004)Σ0.959(Fe3.829Mn0.050)Σ3.879(P2.972S0.058Si0.017)Σ3.047O12. Electron backscatter diffraction was used to confirm the crystal structures of the three new minerals. Raman spectra for all three minerals are also presented.
Copyright and License
© 2024 Mineralogical Society of America.
Acknowledgement
We dedicate this work to the memory of Erin L. Walton, whose enthusiasm for, and prowess with, the Raman spectrometer inspired many studies of minerals, from high-pressure polymorphs in shock veins to the new minerals described in this study; she will be deeply missed—a bright light gone too soon.
We thank Mark Labbe for preparation of the type specimen, and Rebecca Funk for searches of the ICDD-PDF4 database. We thank Nick Gessler (Duke University), and numerous contacts within Somalia and elsewhere for providing access to the material used in this research. We thank two anonymous reviewers for detailed comments that resulted in improvements to the manuscript.
Funding
Funding was provided by Natural Sciences and Engineering Research Council of Canada grant RGPIN-2018-04902 to CDKH. SEM-EBSD analyses were carried out at the Caltech GPS Division Analytical Facility, which is supported, in part, by NSF Grants EAR-0318518 and DMR-0080065.
Additional details
- ISSN
- 1945-3027
- Natural Sciences and Engineering Research Council
- RGPIN-2018-04902
- National Science Foundation
- EAR-0318518
- National Science Foundation
- DMR-0080065