Variations in orientation relationships between rutile inclusions and garnet host relate to magmatic growth zoning
- Author(s)
- Victoria Kohn, Thomas Griffiths, Taisia Alifirova, Nina Daneu, Olga Ageeva, Rainer Abart, Gerlinde Habler
- Abstract
Rutile inclusions in almandine-spessartine garnet from a peraluminous pegmatoid from the Moldanubian zone (Bohemian Massif, AT) show distinct changes in aspect ratio, shape preferred orientations (SPO) and crystallographic orientation relationships (COR) along the transition between microstructurally different growth zones in the garnet core and rim. For identification of the COR characteristics we pool specific CORs based on their common axial relationship into three COR groups: Group 103R/111G, Group 001R/111G and Group 001R/100G. The rutile inclusions in the garnet core domains are elongated along the four Grt111 directions and are dominated by COR Group 103R/111G. The garnet rim zone additionally contains rutile needles elongated along Grt100. Here, Group 001R/111G and 001R/100G are more abundant than in the garnet core. Needle-shaped rutile in the rim shows a systematic correlation between SPOs and CORs as needles elongated parallel to Grt111 are dominated by Group 103R/111G and 001R/111G, whereas those needles elongated parallel to Grt100 exclusively pertain to CORs of 001R/100G. Furthermore, the frequency of each particular SPO in the garnet rim clearly depends on the local growth direction of the particular Grt{112} sector. Facet-specific variations in rutile SPO frequencies in different sectors and growth zones of garnet were observed even between equivalent directions, indicating that the microstructures and textures of rutile inclusions reflect varying parameters of garnet growth. The characteristic differences in COR groups of different garnet growth zones are referred to compositional changes in the bulk melt or compositional boundary layer, associated with magmatic fractional crystallisation.
- Organisation(s)
- Department of Lithospheric Research
- External organisation(s)
- Jožef Stefan Institute (IJS)
- Journal
- Contributions to Mineralogy and Petrology
- Volume
- 179
- No. of pages
- 22
- ISSN
- 0010-7999
- DOI
- https://doi.org/10.1007/s00410-024-02146-9
- Publication date
- 06-2024
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 105120 Petrology
- Keywords
- ASJC Scopus subject areas
- Geochemistry and Petrology
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/154addec-caa1-483c-a9e8-e48490e0ae4a