RECRYSTALLIZED OLIVINE GRAIN SIZE SHOWING TECTONIC EMPLACEMENT HISTORY OF ULTRAMAFIC ROCKS IN THE BLUE RIDGE MOUNTAINS OF WESTERN NORTH CAROLINA
In order to obtain a more detailed emplacement history, we sampled several of these bodies exposed in western North Carolina for studies of their microscopic textures. The grain sizes of the peridotites vary between bodies and grains show annealed textures. The two bodies studied used samples obtained from tailing piles outside of the mines near the towns of Daybook and Frank. Preliminary studies showed the average recrystallized grain size of the Daybook body is 234±103µm while the average grade size of the Frank body is 407±186µm.
Using the average recrystallized grain size in each, we calculated the emplacement paleo-stress conditions using the recrystallized olivine grain size piezometer (Van der Wal, et al., 1993) and found the Daybook body to average at around 13MPa while and the Frank body at 20MPa. Different paleo-stress and textures observed in nearby bodies indicate they could have different emplacement conditions.