REVISITING THE BAIE VERTE FLEXURE: FROM SILURIAN TRANSPRESSION TO DEVONIAN TRANSTENSION, A LONG-LIVED OBLIQUE TRANSFER ZONE, BAIE VERTE PENINSULA, NEWFOUNDLAND APPALACHIANS

On Baie Verte Peninsula, Newfoundland, the Baie Verte Line (BVL) forms a prominent zone of steep WNW-dipping fabrics separating the Laurentian margin rocks (Humber Zone) to the west from ophiolite and arc complexes of the Notre-Dame subzone, to the east. East of the BVL, the main fabrics in the Notre-Dame subzone and Silurian cover are mainly oriented E-W. This abrupt structural curvature is known as the Baie Verte Flexure and is interpreted to be inherited from the original geometry of the Laurentian margin. Correlating fabrics across the BVL is one of the main challenges to resolve the structural evolution of the peninsula. This area has been affected by at least three phases of regional deformation. D₁ fabrics are strongly overprinted west of the BVL and cryptic east of it. D₁ age constraints from the Humber zone range from 468 to 459 Ma, and are interpreted to be related with the obduction of ophiolites during the Ordovician Taconian Orogeny. D₂ represents the main tectonometamorphic phase. Along the BVL, it is associated with penetrative steep SSW-trending fabrics attributed to east-directed thrusting and dated between 427 and 417 Ma. East of the BVL, the main fabric, correlated to S₂, is mainly west-trending, associated with south-directed thrusting, and is younger than 426 Ma. D₂ is interpreted to be related with transpression during the Silurian Salinic Orogeny. D₃ west of the BVL is associated to a SSW-trending crenulation fabric, mainly concentrated along the BVL. Kinematics of D₃ along the BVL suggest dextral down to the west movement. East of the BVL, shallowly-inclined F₃ folds are interpreted to be cogenetic with inversion of reverse faults during dextral transtension. D₃ is contemporaneous with the unroofing of a tectonic window of Humber zone rocks east of the BVL, where timing of deformation and cooling range between 405 and 370 Ma. The long-lived non-coaxial nature of deformation events has played a major role in defining the Baie Verte Flexure. The structure and evolution of northern Baie Verte Peninsula resemble a large-scale long-lived oblique transfer zone between the BVL and the Green Bay Fault, which acted in transpression during the Salinic Orogeny and was later reactivated as a Devonian–Carboniferous transtensional zone.