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Chromite from the Blue Ridge province of North Carolina

January 1, 1984

Accessory chromite in dunite shows a variety of textures that indicate alteration. One group, type A, consists of four types of chromite: clean chromite; lattice chromite, in which the invading chlorite occurs along three directions in the (100) plane; optically zoned chromite; and poikiloblastic chromite. Most of type A chromites are surrounded by chromian clinochlore. The other group, type B, consists of euhedral to subhedral chromite grains which are included in olivine or pyroxene. The accessory chromites define a trend exhibited by chromite from other areas that have undergone metamorphism. Olivine-spinel geothermometry indicates equilibration temperatures near 700 degrees C, roughly consistent with mineral assemblages in the host gneisses. Thus, the Blue Ridge dunites are metamorphic rocks and not primary mantle peridotites.

Publication Year 1984
Title Chromite from the Blue Ridge province of North Carolina
DOI 10.2475/ajs.284.4-5.507
Authors Bruce R. Lipin
Publication Type Article
Publication Subtype Journal Article
Series Title American Journal of Science
Index ID 70013142
Record Source USGS Publications Warehouse
USGS Organization Eastern Mineral and Environmental Resources Science Center