TECTONIC SIGNIFICANCE OF LATE PALEOZOIC DEFORMATION IN THE CAPE GEORGE PENINSULA, ANTIGONISH HIGHLANDS, NOVA-SCOTIA

Late Paleozoic deformation of the Cape George Peninsula, Antigonish Hi ghlands, Nova Scotia, provides information on post-accretionary fault movements associated with waning stages of Appalachian orogenic activi ty. Anomalously intense brittle to ductile deformation of the low-grad e Late Paleozoic rocks of the peninsula occurred along east-west shear zones in a ca. 4 km-wide belt bounded by the NE-trending Hollow and G reendale faults. Deformation adjacent to, and between, these two fault s resulted in brecciation, folding and thrusting, the development of s lickensides on major dislocation surfaces, the local development of S- C fabrics and stretching lineations defined by elongate pebbles, and/o r the production of extensional fractures and veins. The data suggest dextral and subordinate thrust components of movement along the east-w est shear zones. Deformation is attributed to dextrally oblique compre ssion between the bounding Hollow and Greendale faults along which sig nificant reverse displacements are proposed on the basis of fault geom etry and kinematics. The Cape George Peninsula is interpreted as a ''p op-up'' structure between these back-to-back oblique-slip reverse faul ts and is considered to occupy a strongly transpressive step-over zone between them. The east-west shear zones, which record dextral transpr essive motion and steepen towards the north in a positive half-flower structure configuration, are parallel to Reidel R-shears of the shear fracture array and are interpreted to be transfer faults within the st ep-over zone along which oblique slip with dextral and reverse compone nts of motion was transferred from the Hollow Fault to the Greendale F ault. Development of the regional stress regime required by these faul t kinematics is consistent with coeval post-accretionary dextral motio n between the Meguma and Avalon composite terranes along the east-west Cobequid-Chedabucto fault system.