Crystal Structure Controls on Oriented Primary Magnetite Micro-Inclusions in Plagioclase From Oceanic Gabbro
- Author(s)
- Ge Bian, Olga Ageeva, Vladimir Roddatis, Chen Li, Timothy J. Pennycook, Rainer Abart, Gerlinde Habler
- Abstract
Oriented needle-, lath- and plate-shaped magnetite micro-inclusions in rock forming plagioclase from mafic intrusive rocks, were investigated using correlated optical microscopy and scanning transmission electron microscopy. The magnetite micro-inclusions were analysed on cuts parallel and perpendicular to the inclusion-elongation directions. The crystal structures of the two phases are in direct contact along the interfaces. The shape, shape orientation and crystallographic orientation relationships between the magnetite micro-inclusions and the plagioclase host appear to be controlled by the tendency of the system to optimise lattice match along the interfaces. The elongation direction of the inclusions ensures good match between prominent oxygen layers in the magnetite and plagioclase crystal structures across the interfaces bounding the inclusions parallel to their elongation direction. In cross-section, additional modes of lattice match, such as the commensurate impingement of magnetite and plagioclase lattice planes along the interfaces, the parallel alignment of the interfaces to low-index lattice planes of magnetite or plagioclase, or the parallel alignment to low index lattice planes of both phases are observed, which appear to control the selection of interface facets, as well as the shape and crystallographic orientation relationships between magnetite micro-inclusions and plagioclase host. The systematics of the inclusion cross-sectional shapes and crystallographic orientation relationships indicate recrystallisation of magnetite with potential implications for natural remanent magnetisation of magnetite-bearing plagioclase grains.
- Organisation(s)
- Department of Lithospheric Research
- External organisation(s)
- Russian Academy of Sciences, University of Antwerp, Helmholtz-Zentrum Potsdam Deutsches GeoForschungsZentrum
- Journal
- Journal of Petrology
- Volume
- 64
- ISSN
- 0022-3530
- DOI
- https://doi.org/10.1093/petrology/egad008
- Publication date
- 03-2023
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 105116 Mineralogy, 105113 Crystallography, 105120 Petrology
- Keywords
- ASJC Scopus subject areas
- Geochemistry and Petrology, Geophysics
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/73817230-5674-4127-b41b-8e1a2281c780