Microstructures

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Grain Boundary Migration
Natural Examples

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47. Grain boundary migration in naturally deformed feldspar - Preserved lobate grain boundary migration textures between two feldspar grains from granulite grade felsic gneiss in the core of the Vredefort dome, near Potchefstroom, South Africa.

FOV 0.8 mm, Nicols Crossed + Gypsum Plate.

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48. Grain boundary migration in naturally deformed feldspar - Grain boundary migration has produced the sutured grain boundaries between feldspar grains in this sample of mylonitic Port Deposit gneiss, from the Maryland banks of the Susquehanna River near Interstate 95. Optically visible internal lattice strain is restricted to minor deformation bands. Rare subgrains around feldspar grain margins are the result of grain boundary migration recrystallization.

FOV 1.5 mm, Nicols Crossed.

Grain Boundary Migration Natural Examples	Click image to enlarge
47. Grain boundary migration in naturally deformed feldspar - Preserved lobate grain boundary migration textures between two feldspar grains from granulite grade felsic gneiss in the core of the Vredefort dome, near Potchefstroom, South Africa. FOV 0.8 mm, Nicols Crossed + Gypsum Plate. Click here to view Flash animation in a new window.
48. Grain boundary migration in naturally deformed feldspar - Grain boundary migration has produced the sutured grain boundaries between feldspar grains in this sample of mylonitic Port Deposit gneiss, from the Maryland banks of the Susquehanna River near Interstate 95. Optically visible internal lattice strain is restricted to minor deformation bands. Rare subgrains around feldspar grain margins are the result of grain boundary migration recrystallization. FOV 1.5 mm, Nicols Crossed.