Shape - texture relations

6.5

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Shape - texture relations

In order to derive the relation between grain shape and c-axis orientation) of the old grains of experimentally deformed Black Hills quartzite (sample CQ78C, page 4.3), the microstructure is subdivided into three orientation domains: c-axes with misorientation 0°- 30°, 30°-60°, and 60°-90° about the compression direction. For each partial microstructure the axial ratio of, b/a (short/long), has been evaluated (using NIH Image) and plotted as a function of size (radius r of equivalent circle). The average b/a value for all grains with a diameter of > 50 µm (r > 25 µm), is determined. b/a decreases with increasing misorientation of the c-axis from the compression direction, indicating that grains with c-axis orientations subparallel to the compression direction are least flattened.

c-axis misorientation 0°-30°

c-axis misorientation 30°-60°

c-axis misorientation 60°-90

6.5	WHERE CAN WE GO FROM HERE ?
	top / contents / section 6 / pages -- 6.1 -- 6.2 -- 6.3 -- 6.4 -- 6.5 -- 6.6 -- 6.7 -- 6.8

		Shape - texture relations
		In order to derive the relation between grain shape and c-axis orientation) of the old grains of experimentally deformed Black Hills quartzite (sample CQ78C, page 4.3), the microstructure is subdivided into three orientation domains: c-axes with misorientation 0°- 30°, 30°-60°, and 60°-90° about the compression direction. For each partial microstructure the axial ratio of, b/a (short/long), has been evaluated (using NIH Image) and plotted as a function of size (radius r of equivalent circle). The average b/a value for all grains with a diameter of > 50 µm (r > 25 µm), is determined. b/a decreases with increasing misorientation of the c-axis from the compression direction, indicating that grains with c-axis orientations subparallel to the compression direction are least flattened.
		c-axis misorientation 0°-30°
		c-axis misorientation 30°-60°
		c-axis misorientation 60°-90