Orogenic architecture diagrams to reconstruct paleogeography and plate tectonics: Newfoundland (Canada) as a case study

Reconstructing palaeogeography from accretionary records is challenging owing to the difficulty of integrating data sources transcending a range of fields and scales. Here, we present the ‘orogenic architecture diagram’ method to systematically compile geological data in temporal and spatial context at the scale of the ‘building blocks’ of orogens and to use their interpreted geological histories as a base for tectonic and palaeogeographical reconstruction. We identify lower plate-derived Continental or Ocean Plate Stratigraphy, and upper plate-derived ophiolites and magmatic units. We apply this framework to the Newfoundland Appalachians, Canada, which record accretion of oceanic and Gondwana- and Laurentia-derived continental units to Laurentia during the Cambro-Ordovician closure of the Iapetus Ocean. Our diagrams allow for straightforward connection of modern geological records to opening and closure of marginal oceanic basins and illustrate that the Iapetus Ocean itself left little accretionary record. Our approach highlights the source of contrasting interpretations in Newfoundland reconstructions and may motivate targeted field campaigns here and elsewhere within the orogen to interrogate proposed models. Our application to Newfoundland also demonstrates that our protocol, based on modern-style plate tectonics and orogenesis, still applies to early Paleozoic orogens and may provide a tool to reconstruct the emergence of plate tectonics.