01978nas a2200145   4500008004100000022001400041245018200055210006900237490000800306520140600314100001601720700001601736700001901752856006101771       2024                        eng d  a0305-871900aTerminal Ediacaran-Late Ordovician evolution of the NE Laurentia palaeocontinent: rift–drift-onset of Taconic orogeny, sea-level change, and ‘Hawke Bay’ onlap (not offlap)0 aTerminal EdiacaranLate Ordovician evolution of the NE Laurentia 0 v5423 a<div role="paragraph">Rodinia breakup with late Ediacaran rifting defined a NE Laurentia triple junction (New York Promontory-Ottawa-Bonnechere aulacogen (OBA)-Quebec Reentrant). Rifting persisted to c. 510 Ma. The oldest passive margin shelf units (Forestdale, Moosalamoo) underlie a sandstone (Cheshire) commonly regarded as the oldest passive unit. Late Dyeran–Middle Cambrian rifting led to the oldest OBa sedimentation and formed the Franklin Basin (NW Vermont). Cambrian-Darriwillian shelf-slope facies are linked eustatically-not Taconic orogeny onset. Onlap and shelf carbonates are coeval with black slope mud; lowstand shelf unconformities with green, oxic slope mud. Early-middle Dyeran eustatic change defined slope units: 1) Browns Pond dysoxic/anoxic (d/a) interval with debrite cap (Holcombville Member, new); 2) Middle Granville oxic interval (new); and 3) lower Hatch Hill d/a interval. Our analysis leads to two controversial conclusions: (i) existence of the Dashwoods and other micro-continental blocks due to hyper-extension is not supported by cover sequences linking Laurentia to proposed Dashwoods areas (i.e., Green Mountains) and an arc origin of the type Dashwoods, and (ii) ‘Hawke Bay Event(s),’ widely interpreted as Cambrian global regressive event(s), is a local HST facies with shelf sand by-pass onto the Hatch Hill slope in its NE Laurentia type region.</div>
1 aLanding, E.1 aWebster, M.1 aBowser, S., S.  uhttps://www.lyellcollection.org/doi/10.1144/SP542-2023-4