Abstract

Structures associated with dextral transcurrent displacement on the Finlay – Ingenika fault are characterized predominantly by subvertical to vertical faults. Intersections of the fault planes with planar fabrics are all subvertical. This geometry, together with the common occurrence of subhorizontal slickenlines and stretching lineations in some strongly deformed fault zones, indicates their strike-slip nature. Principal directions of the strain ellipsoids determined from the deformed volcanic fragments along one of the faults are in accordance with those of the magnetic susceptibility ellipsoids from the adjacent plutonic rocks, indicating that the plutonic rocks experienced the same deformation as the Late Triassic Takla Group volcanics. Regional cleavage within the fault-bounded blocks indicates that the blocks were nonuniformly rotated clockwise about subvertical axes in response to progressive dextral transcurrent displacement on the Finlay – Ingenika fault. The mode of deformation observed in the area may characterize many parts of the Intermontane Belt.

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