Taconian Obduction and Silurian Exhumation of the Betts Cove Ophiolite, Canadian Appalachians.

• Published in: The Journal of Geology
• Main Authors: Tremblay, Alain, Bédard, Jean H., Lauzière, Kathleen
• Format: Article in Journal/Newspaper
• Language: English
• Published: 1997
• Subjects: exhumation; obduction; ophiolite; Silurian; Taconic orogeny; Verte; Baie Verte; Baie Verte Peninsula; Betts Cove; Cape St. John; Snooks Arm; Newfoundland
• Online Access: https://espace.inrs.ca/id/eprint/9449/; https://espace.inrs.ca/id/eprint/9449/1/P449.pdf; https://doi.org/10.1086/515976

In the Newfoundland Appalachians, the Betts Cove Complex and cover rocksof the Snooks Arm Group form a composite section of Ordovician marginal oceanic crust that is unconformably overlain by Silurian terrestrial sedimentary rocks and bimodal volcanics of the Cape St. John Group. Tectonic fabrics that characterize both the Ordovician and the Silurian rock sequences are subdivided into pre‐ to syn‐obduction (Taconian) structures, Silurian extensional structures, and Acadian compressional structures. Pre‐obduction structures consist of syn‐oceanic normal faults in the Betts Cove ophiolite. Thrusting fabrics found along parts of the contact between the ophiolite and the Snooks Arm Group are attributed to the obduction of the oceanic crust over the Laurentian margin during the Taconian orogeny. Normal faults and shear zones of inferred Silurian age are preserved in the Snooks Arm Group and along the contact with the Cape St. John Group. These faults are contemporaneous with Silurian sedimentation and magmatism and are attributed to the exhumation of the oceanic crust. Southeast‐verging reverse faults and folds that characterize the regional deformation in the Baie Verte peninsula postdate the exhumation and are attributed to compressive deformation related to the Devonian Acadian orogeny.