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Abstract
The Brevard fault zone (BFZ) forms a striking, 375 km-long lineament that runs from eastern Alabama to Virginia. Boreholes drilled for the Chattahoochee Tunnel Project provided fresh, unweathered samples which were studied to develop tighter constraints on the metamorphic and deformational history of the BFZ. Quartz mica schists and mica schists have experienced two prograde, Barrovian style, amphibolite grade metamorphic events (M1, M2) and a fluid enhanced metasomatic event (M3). M1 is defined by a relict metamorphic assemblage of garnet-staurolite. A second period of garnet growth and the development of muscovite-biotite define the S2 foliation and the M2 assemblage. M3 is indicated by the minerals calcite, chlorite and epidote which are commonly found in crosscutting veins. Three ductile deformational events (D2, D3, and D4) produced a strong penetrative foliation, (S2), tight to close folds, (F3), and open to gentle folds, (F4); a later brittle event (D5) produced fractures and psuedotachylyte.