Abstract

Small-scale subvertical shear zones developed parallel to a regional preexisting S2 schistosity exhibit evidence of a complex shearing history recorded by conflicting kinematic indicators in both crosssection and plan view. The concordant schistosity internal to the shear zones contains a steeply plunging stretching lineation. Coexisting kinematic indicators of non-coaxial deformation parallel to this lineation are compatible with reverse dip-slip. This earliest shearing event was characterized by (1) the development of several shear discontinuities along selected preexisting S2 foliation surfaces, (2) subvertical transposition of both bedding and the oldest (S1) flat-lying foliation, and (3) by the emplacement of shear veins along the S2 foliation planes. The youngest shearing event reactivated the foliation-parallel shear discontinuities as dextral shear planes, thereby causing concomitant subhorizontal retransposition, east–west subhorizontal stretching, and emplacement of en echelon extension veins. A single set of shear bands occurring at a clockwise acute angle to the slipping foliation indicates that small-scale shear zones were transpressional during the late dextral shearing.

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