A Barrovian Overprint Superimposed on Partly Preserved High-Pressure Metamorphic Rocks: Pressure–Temperature–Time Evolution in the Ordovician Corner Brook Collisional Complex (Western Newfoundland, Canada).

This article focuses on the metamorphic evolution and geodynamic history of the Corner Brook Collisional Complex (CBCC) in western Newfoundland, an exhumed segment of the Humber margin of Laurentia partially subducted during the Ordovician Taconic orogeny. Detailed pressure–temperature–time (PTt) paths derived from pseudosection modeling and geochronological data reveal a bimodal metamorphic history: one group of rocks records high-pressure subduction followed by exhumation and Barrovian metamorphism around 438 ± 14 Ma, while a second group lacks a high-pressure stage and reflects mid-crustal conditions with a later tectonometamorphic overprint near 427 ± 6 Ma. The study proposes a five-stage geodynamic model involving early mid-crustal stacking, maximum subduction to high-pressure conditions, return flow and thermal relaxation, renewed mid-crustal stacking with fluid infiltration, and late-stage folding and thrusting that formed an elongated metamorphic dome. These findings clarify the complex collisional and metamorphic processes affecting the Humber margin during the Taconic and Silurian orogenic cycles.