Terrane history of the Iapetus Ocean as preserved in the northern Appalachians and western Caledonides

The Iapetus Ocean was the first ancient ocean to be identified following development of plate tectonics; its history has been fundamental in relating orogenesis and motion. probably formed 3-way rifting between Laurentia, Baltica, Amazonia – West Africa (a block that became incorporated Gondwana). Closure trapped numerous terranes during Appalachian–Caledonide Orogen. Subsequent deformation, including late Paleozoic strike slip, transpression, transtension, Mesozoic stretching Pangea breakup, must taken into account models for orogen development. Traditional analyses Iapetan have focussed on Cambrian sedimentary successions, isotopic criteria, classify larger domains: Ganderia, Avalonia Megumia. Detrital zircon data show these domains did not cross as single entities, while paleomagnetic reveal significant vertical-axis terrane rotations. We here review interpret 17 poles >350 published detrital sets from northern Appalachians western Caledonides, using consistent rigorous criteria selection presentation data. place an integrated stratigraphic chart timing relations seek constraints provenance travel Ocean. distinguish groups likely travelled together assemblages. In Taconian/Grampian Orogeny, Furongian Katian continent–arc collision involved off-margin blocks along hyperextended Laurentian margin. New England, early Taconian by 475 Ma Gondwana-derived Moretown assemblage. An assemblage Bronson Popelogan arc arrived at main margin 25-30 Myr later. Subduction polarity reversal then led progressive accretion additional assemblages (Salinian Orogeny). Miramichi–Victoria close Ordovician–Silurian boundary. Miramichi underwent partial subduction Québec re-entrant, whereas Victoria juxtaposed with Newfoundland promontory without major metamorphism. mid-Silurian time, Gander related portions Britain Ireland accreted Baltica (Scandian St. Croix La Poile may slightly later, but is distinguished a Silurian arc–backarc system (coastal igneous belt) above northwest-dipping zone. Avalon–Brookville encountered this Přídolí Middle Devonian time (Acadian Orogeny), leading collapse backarc basin northwest-vergent thrust emplacement onto Laurentia sinistral transpression Appalachian Acadian deformation mainly slip Ireland. Several were carried internal records earlier took near Early Ordovician (Monian/Penobscottian thus contained complex array terranes, small basins, arcs, previously emplaced ophiolites analogous modern southeast Asia. It closed form sutures within which no suture can clearly identified.