Abstract

This contribution provides an overview of the geological setting, stratigraphy, tectono-sedimentary evolution, and paleogeography of the post-Taconian–pre-Carboniferous sequence of the Gaspé Belt. The sequence has been shaped by two tectonic pulses: the Salinic disturbance that began during the Early Silurian (Telychian) and persisted until the Early Devonian (Pragian), and the ensuing Acadian Orogeny in the Early to Mid-Devonian (Emsian-Eifelian).

The shelf and shelf-edge history at the Laurentian margin along the Québec Re-entrant–St. Lawrence Promontory can be summarized in five broad phases that resulted from the interplay of tectonics and sea-level change. Phase 1 is a Llandoverian–Wenlockian regressive phase (R1) related to post-Taconian successor basin infilling, which culminated in extensive carbonate platform development. Phase 2 is a late Wenlockian–Ludlovian transgressive phase (T1). Phase 3 corresponds to a later Ludlovian-Pridolian second regressive phase (R2). Phases 2 and 3 were accompanied by extension faulting, block tilting, and the development of reefs, reef complexes and reef tracts along the Gaspé–Témiscouata shelf. Phase 4 is an Early Devonian phase of accelerated subsidence (transgression T2) affecting the northwestern part (Québec Re-entrant area), while the southeastern part (St-Lawrence Promontory area) was previously uplifted as a result of Laurentia colliding with the western margin of Gondwana-related terranes to the south. Phase 5 is the final regression (R3) related to the Acadian Orogeny.

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