A discussion of pyrrhotite fabrics

Abstract

The classification of pyrrhotite fabrics proposed by Lusk and Ostwald identifies E-type pyrrhotite, which has no dimensional or crystallographic preferred orientation and an equant grain shape, and F-type pyrrhotite, which has a distinct dimensional and crystallographic preferred orientation and flattened, elongate grain shapes. The results of an analysis of pyrrhotite fabrics studied for Ducktown, Tennessee, do not conform with this classification. The data suggest that the three parameters, crystallographic orientation, dimensional orientation, and grain shape, are independent. Therefore, the E- and F-type classification of pyrrhotite fabrics appears not to have universal applicability.