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Progressive localization of strain within the Songpan—Garzê Fold Belt, at the eastern margin of the Tibetan Plateau, has resulted in the formation of the Wenchuan—Maowen Shear Zone and preservation of excellent overprinting relationships between three major phases of ductile and semi-ductile deformation. These relationships show that deformation in the eastern Songpan—Garzê Fold Belt evolved from crustal thickening during SW-directed compression (D₁) to localized sinistral transcurrent shear (D₂) and finally to increasingly localized high temperature (D_3p) and retrograde (D_3r) reverse shear in response to SE-directed compression. Both D₂ and D₃ deformations were co-planar and reactivation of the S₂ foliation led to the formation of a composite S_2–3 fabric. However, inclusion trails in garnet porphyroblasts preserve evidence of a transition between these strike-slip and reverse shear end members …