Triassic–Jurassic Accretionary History and Tectonic Origin of Stikinia From U‐Pb Geochronology and Lu‐Hf Isotope Analysis, British Columbia

Abstract The timing of assembly and tectonic origins terranes in the northern Cordillera Alaska, British Columbia, Pacific Northwest are debated. Stikinia, a long‐lived arc terrane, has an enigmatic regional Mesozoic accretionary history its remain unconstrained. Zircon U‐Pb geochronology Lu‐Hf isotopic data on Triassic–Jurassic sedimentary igneous rocks from central Stikinia shed light terrane‐scale effects latest Triassic–Early Jurassic collision between pericratonic Yukon‐Tanana terrane. Main age peaks 250–160 Ma, reflecting ongoing arc‐related activity within Stikinia. Comparison evolution unconformity development (Whitehorse trough) provide new constraints Triassic–earliest deformation. We attribute shortening‐related deformation to variable along‐strike interactions during end‐on with significant crustal thickening at apex that did not persist farther south. A small pre‐Devonian zircon population is significant, as oldest exposed Early Devonian. Pre‐Devonian differ those but resemble zircons southern Wrangellia. These likely multi‐cyclic, derived crust originated Arctic region near end Caledonide orogeny. suggest was independent block prior Triassic onset ongoing, turn promoted oroclinal peri‐Laurentian terranes.