Coherent lamellar intergrowth in alkali feldspar
- Author(s)
- Elena Petrishcheva, David Andreas Heuser, Rainer Abart
- Abstract
A thermodynamic analysis of coherent lamellar intergrowth resulting from the exsolution of initially homogeneous alkali feldspar is presented. In contrast to earlier treatments, where the simplifying assumption of zero strain in the lamellar interfaces was used, our treatment is more general. The elastic stresses and strains associated with coherent lamellar intergrowth of Na-rich and K-rich alkali feldspar are calculated by minimising the overall elastic energy of the lamellar microstructure. At given pressure and temperature, the elastic energy depends on the volume proportions of the two lamellar types, and thus on the composition of the homogeneous precursor feldspar. As a consequence, there is no single coherent solvus for alkali feldspar, but coherent solvi are different for different compositions of the homogeneous precursor phase. Experimentally observed lamellar orientations agree with those predicted by minimising the strain energy on a set of all possible lamellar orientations.
- Organisation(s)
- Department of Lithospheric Research
- Journal
- Contributions to Mineralogy and Petrology
- Volume
- 178
- ISSN
- 0010-7999
- DOI
- https://doi.org/10.1007/s00410-023-02059-z
- Publication date
- 11-2023
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 105120 Petrology
- Keywords
- ASJC Scopus subject areas
- Geochemistry and Petrology, Geophysics
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/493bacbf-fcee-4656-8fcc-bd83d73b87ef