THE COASTAL TO NEARSHORE-MARINE RECORD OF THE NYEBOE FORMATION, FURY AND HECLA GROUP: TOWARDS A TECTONO-STRATIGRAPHIC REFINEMENT OF THE BYLOT BASINS, NUNAVUT, ARCTIC CANADA

Intracontinental basin formation during the amalgamation of supercontinents is well-documented yet not fully understood. Discerning depositional environments from facies analysis and placing this information within a structural context is critical for determining the tectono-stratigraphic evolution of these types of basins. The latest Mesoproterozoic (~1.1 Ga) Fury and Hecla Basin on the Melville Peninsula and Baffin Island (Nunavut, Arctic Canada) is broadly stratigraphically correlated with the Thule, Aston-Hunting and Borden basins, which are collectively referred to as the Bylot basins. The lowermost unit in the Fury and Hecla Group is the Nyeboe Formation, for which we present the results of recent fieldwork. The Nyeboe Formation comprises five distinct facies associations: alluvial to fluvial, marine backshore, marine intertidal, marine foreshore to shoreface, and marine offshore. Mafic units also occur in the lower Fury and Hecla Group, including at least one basaltic flow. Although relationships between facies associations are complex, an overall fining-upward, transgressive trend from a coast-proximal terrestrial system to a nearshore marine environment is recognized. Strata are predominantly attributed to a wave-dominated, shallow-marine environment, implying a long-term near-steady state between subsidence and sediment accumulation. Considering both the along-strike and -dip thickness trends, mafic rock units and basin-bounding faults, we infer the basin originated as a half-graben. Paleoflows oblique to the inferred master faults suggest that the interplay between basin topography and longshore drift mediated the sediment dispersal pattern. These results bear important implications for the correlation of the Fury and Hecla and the other Bylot basins and contribute to the debates regarding intracontinental-basin formation during supercontinent amalgamation.