Title

The Petrography of the Buck Creek Dunite Body, Clay County, NC: Implications about its Origin and Emplacement

Degree Year

1998

Document Type

Thesis

Degree Name

Bachelor of Arts

Department

Geology

Abstract

The Buck Creek dunite body, which is part of the Chunky Gal mafic and ultramafic complex, is well exposed on Corundum Knob in Clay County, North Carolina. These ultramafic rocks are surrounded here by mafic schists and gneisses. Gradational geochemical / mineralogical contacts between the mafic and ultramafic rocks of the this complex imply the same protolith for both rock types. They may have originated as distinct parts of an ophiolitic suite beneath a mid-ocean spreading ridge. The metamorphic history of these ophiolitic rocks suggest further that they were subdued to depths of -18km before being emplaced along fault zones in the present day Blue Ridge Province. Buck Creek dunites are generally unserpentinized, and display microstructures and crystallographic preferred orientations indicative of a simple shear deformation via dislocation creep. The degree of recystallization in deformed olivines here implies elevated temperature / pressure conditions such as those found in collisional events. The large size of recrystallized grains and the apparentlyl low dislocation densities in olivine indicates low differential stresses, also consistent with high temperature crustal deformation.

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