Brownleeite: A New Manganese Silicide Mineral in an Interplanetary Dust Particle

Authors

Keiko Nakamura-Messenger, Astromaterials Research and Exploration Science Directorate, NASA, Johnson Space Center and ESCG/Jacobs Technology
Lindsay P. Keller, Astromaterials Research and Exploration Science Directorate, NASA, Johnson Space CenterFollow
Simon J. Clemett, Astromaterials Research and Exploration Science Directorate, NASA, Johnson Space Center and ESCG/ERC Inc.
Scott Messenger, Astromaterials Research and Exploration Science Directorate, NASA, Johnson Space Center
John H. Jones, Astromaterials Research and Exploration Science Directorate, NASA, Johnson Space CenterFollow
Russel L. Palma, Minnesota State University - MankatoFollow
Robert O. Pepin, University of Minnesota - Twin CitiesFollow
Wolfgang Klöck, Röntgenanalytik Messtechnik GmbH
Michael E. Zolensky, Astromaterials Research and Exploration Science Directorate, NASA, Johnson Space Center
Hirokazu Tatsuoka, Shizuoka University

Document Type

Article

Publication Date

2010

Abstract

Brownleeite, ideally stoichiometric MnSi, is a manganese silicide not previously observed in nature that was discovered within an interplanetary dust particle that likely originated from a comet. Three submicrometer brownleeite grains were found, with one of them poikilitically enclosed by Mn-bearing forsterite. Owing to the small size of the brownleeite grains, it was not possible to determine conventional macroscopic properties of this mineral; however, the chemical composition and crystal structure were well constrained by extensive quantitative energy dispersive X-ray analysis and electron diffraction using transmission electron microscopy (TEM). The crystal system for brownleeite is cubic (a = 4.557 Å) with space group P2₁3, cell volume = 94.63 ų, Z = 4, density (calculated) = 2.913 g/cm³, and empirical formula: (Mn_0.77Fe_0.18Cr_0.05)Si. These brownleeite grains likely formed as high-temperature condensates either in the early Solar System or in the outflow of an evolved star or supernova explosion.

Department

Physics and Astronomy

Publication Title

American Mineralogist

Recommended Citation

K. Nakamura-Messenger, L.P. Keller, S.J. Clemett, S. Messenger, J.H. Jones, R.L. Palma, R.O. Pepin, W. Klöck, M.E. Zolensky, and H. Tatsuoka, 2010. Brownleeite: a New Manganese Silicide Mineral in an Interplanetary Dust Particle. American Mineralogist 95, 221-228.

DOI

10.2138/am.2010.3263

Link to Publisher Version (DOI)

https://doi.org/10.2138/am.2010.3263

Publisher's Copyright and Source

Copyright © 2010 American Mineralogist. Article published by American Mineralogist in American Mineralogist, volume 95, issue number 2-3, 2010, pages 221-228. Available online: https://doi.org/10.2138/am.2010.3263