Latest Silurian syntectonic sedimentation and magmatism and Early Devonian orogenic gold mineralization, central Newfoundland Appalachians, Canada: Setting, structure, lithogeochemistry, and high-precision U-Pb geochronology

Abstract The eastern Dunnage Zone of the central Newfoundland Appalachians hosts Paleozoic orogenic gold mineralization along a northeast-trending, crustal-scale fault corridor that extends for more than 200 km. This system is characterized by polyphase, structurally controlled, quartz vein systems cut Neoproterozoic granitoid rocks and unconformably overlying syntectonic, polymict conglomerate associated transitional to calc-alkaline bimodal igneous rocks. High-precision chemical abrasion–isotope dilution–thermal ionization mass spectrometry (CA-ID-TIMS) U-Pb geochronology confirms widespread, latest Silurian magmatic pulse (422–420 Ma) attributed transient phase lithospheric extension resulting from asthenospheric crustal melting related slab break-off. Syntectonic was deposited as basal unit during extension-related uplift erosion lasted until ca. 418 Ma in north-central Newfoundland. Orogenic with syntectonic sedimentation magmatism hosted within third-order shear form offshoots triangle zone–like structural between southeast- northwest-dipping, second-order splays zones. southeast-dipping formed northwest migration Acadian thrust front, whereas northwest-dipping faults zones are Salinic structures were reactivated Early Devonian. Primary hydrothermal rutile gold-mineralized veins produced ages 410 Ma. These consistent emplacement result fluid-pressure cycling far-field compression thermal perturbations Devonian cycle. setting process evolution district remarkably similar world-class Canadian Shield.