Directed growth of a sector-zoned garnet in a pegmatoid from the Bohemian Massif, Austria
- Author(s)
- Victoria Kohn, Taisia Alifirova, Nina Daneu, Thomas Griffiths, Eugen Libowitzky, Manfred Linner, Andreas Ertl, Rainer Abart, Gerlinde Habler
- Abstract
Almandine-spessartine garnet from the Moldanubian Zone in the Bohemian Massif (Austria) records microstructural and compositional features of crystal growth imprinted during the transition from pegmatoid magmatic to subsolidus state. Directed garnet growth results in asymmetric compositional, morphological and microstructural zoning. In addition, the garnet core shows sector zoning reflected by the predominance of phosphate inclusions in {110} sectors, and rutile inclusions in {112} sectors of garnet. These sector-specific abundances of inclusions are also expressed in the electron probe microanalytical data of the non-equivalent garnet sectors. The contribution of the submicron and nano-inclusions of phosphates and rutile is of crucial importance for thermobarometric methods based on P, Na and Ti in garnet. The sector-specific abundance of inclusions is referred to the surface configuration of individual garnet facets. Contrastingly, the microstructural growth banding observed in the {112} garnet sectors supposedly results from compositional fluctuations of a boundary layer at the garnet-melt interface. These fluctuations control the details of the inclusion microstructures, which differ even in crystallographically equivalent sectors.
- Organisation(s)
- Department of Lithospheric Research, Department of Mineralogy and Crystallography
- External organisation(s)
- Jožef Stefan Institute (IJS), GeoSphere Austria, Naturhistorisches Museum Wien (NHM)
- Journal
- Lithos
- Volume
- 466-467
- No. of pages
- 19
- ISSN
- 0024-4937
- DOI
- https://doi.org/10.1016/j.lithos.2023.107461
- Publication date
- 02-2024
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 105120 Petrology, 105116 Mineralogy
- Keywords
- ASJC Scopus subject areas
- Geochemistry and Petrology, Geology
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/754569f0-9456-41f8-b43b-e3720ecbf470