Abstract
The structure of grain boundaries in a granite-origin ultramylonite, composed mainly of fine-grained feldspar and quartz, was studied by high-resolution electron microscopy (HREM). At most of the boundaries, not only between the same minerals but also between different minerals, lattice fringes in adjacent grains meet at the interface with no other appreciable phases. In these boundaries, some of the straight segments correspond to a low-index plane of one of the connected grains. Boundaries containing voids, with a spheroidal shape elongated along the boundaries, were observed only between quartz grains. It is suggested that these boundaries were formed by healing of microcracks. The structural width of major boundaries, deduced from lattice-fringe imaging, is less than about 0.5 nm.
Original language | English |
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Pages (from-to) | 617-623 |
Number of pages | 7 |
Journal | Physics and Chemistry of Minerals |
Volume | 26 |
Issue number | 8 |
DOIs | |
Publication status | Published - 1999 Sep 1 |
Keywords
- Grain boundary
- High-resolution electron microscopy
- Lattice fringe
- Ultramylonite
ASJC Scopus subject areas
- Geochemistry and Petrology
- Materials Science(all)