See more from this Division: Topical Sessions
See more from this Session: Mid- to Lower Crustal Deformation Processes: Strain, Kinematics and Relationships to Upper Crustal Structures
Abstract:
Large faults provide greater insight into the burial and unroofing history of the SA. The multiply reactivated Brevard fault (BF) (VA to AL), and Alleghanian Box Ankle (BA, thrust), Towaliga (T, dextral), and Dean Creek (DC, dextral) faults framing the Pine Mountain window in GA and AL record PT conditions reflecting movement at mid- to upper crustal conditions at different times. The BF moved >400 km during high temperature conditions as it buttressed mid-crustal, tectonically forced, SW-directed channel flow during Acadian-Neoacadian A-subduction of the eastern BR and IP beneath CS. This fault was reactivated dextrally ~280 Ma (Alleghanian) under gs conditions, and again shortly thereafter as a brittle thrust during BR-Piedmont megathrust sheetemplacement. This sequence of BF reactivation highlights deformation as the crust was uplifted and BR and Piedmont elements were progressively unroofed. A parallel scenario exists along the BA, T, and DC faults that moved only once, but under sill I, garnet (retrograding sill I), and gs facies conditions, respectively.
See more from this Division: Topical Sessions
See more from this Session: Mid- to Lower Crustal Deformation Processes: Strain, Kinematics and Relationships to Upper Crustal Structures