PALEOZOIC AND MESOZOIC METALLOGENIC AND TECTONIC HISTORY OF THE WRANGELLIA COMPOSITE TERRANE IN ALASKA AND THE CANADIAN CORDILLERA

The Wrangellia composite terrane (Alexander, Peninsular, and Wrangellia terranes) exhibits a long and complicated metallogenic and tectonic history. The major Paleozoic and Mesozoic metallogenic and tectonic events are: (1) Neoproterozoic formation of volcanogenic massive sulfide deposits in a back arc in the Alexander terrane; (2) Ordovician-Silurian formation of porphyry Cu-Mo and associated deposits hosted in plutons in a continental-margin arc in the Alexander terrane; (3) Middle and Late Devonian formation of kuroko massive sulfide deposits in island-arc volcanic units in the Wrangellia terrane; (4) Pennsylvanian and Permian formation of Cu skarn, porphyry Cu, and kuroko massive sulfide deposits in the Skolai island arc in the Wrangellia terrane; (5) Late Triassic formation of podiform Cr and stratiform PGE deposits in subduction-related mafic and ultramafic plutons in the basal part of the Talkeetna-Bonzana island arc in the Wrangellia terrane; and formation of gabbroic Ni-Cu, stratiform PGE, and Cyprus and Kuroko massive sulfide deposits in the Nikolai Greenstone and correlative units during back-arc rifting of the Wrangellia and Alexander terranes; (6) Early Jurassic formation of Cu and Fe skarn, kuroko massive sulfide, and porphyry Cu and related deposits in the Talkeetna-Bonanza island arc in the Peninsular, Wrangellia, and Alexander terranes; (7) Late Jurassic formation of porphyry Cu and related deposits in the subduction-related granitoid plutons, and formation of zoned mafic-ultramafic PGE-Cr-Ti deposits in subduction-related mafic and ultramafic plutons of the Gravina island arc in Wrangellia terrane. (8) Early Cretaceous formation of porphyry Mo and associated deposits, and kuroko massive sulfide deposits in volcanic units of the Gravina island arc in Wrangellia terrane. (9) Late Early Cretaceous formation of porphyry Mo, Cu skarn, polymetallic vein, and manto deposits in the Omineca-Selwyn collisional plutonic belt that is interpreted as forming during final accretion of Wrangellia composite terrane to North American continental margin; And (10) Early Late Cretaceous formation of granitoid-related, Au- and Cu-Ag quartz vein, and Kennecott Cu deposits during anatexis and regional metamorphism associated with the final accretion of the Wrangellia composite terrane.