Franklinian Composite Tectono-Sedimentary Element, Canadian Arctic Islands

Abstract The Neoproterozoic–Devonian strata of the Canadian Arctic Islands record three Tectono-Sedimentary Elements (TSEs): (i) the Neoproterozoic Synrift TSE; (ii) the Neoproterozoic–Late Devonian Franklinian Margin TSE composed of Cambrian–Ordovician carbonate-dominated passive-margin strata and latest Ordovician, Silurian and Lower Devonian mixed carbonate and clastic strata deposited on an unstable margin; and (iii) Middle–Upper Devonian Foreland Basin TSE deposited in an expanding foreland basin. These three TSEs comprise the Franklinian Composite Tectono-Sedimentary Element (CTSE). In the southern parts of the Arctic Islands, strata are flat lying but there is localized faulting and folding in the central Arctic Islands and towards the northern end of the Franklinian CTSE. These strata of the Franklinian Margin and Foreland Basin TSEs were broadly folded over deeply seated reverse faults localized along Late Silurian–Early Devonian contractional uplifts or deformed by widespread Late Devonian thin-skin folds and thrusts related to the Ellesmerian Orogeny. The parts of the CTSE overprinted by Late Silurian–Early Devonian north–south-trending structures are grouped as Boothia Structural Domains, and the area of the CTSE overprinted by Ellesmerian structures is termed the Ellesmerian Structural Domain. The major hydrocarbon source rock is Upper Ordovician–Lower Silurian shale but maximum thermal maturity over much of the area was achieved by the Late Devonian, prior to the formation of large folds. The complex geological history of the area since the Late Devonian reduces the chances of hydrocarbon preservation.