Sedimentology and stratigraphy of a thick, areally extensive fluvial-marine transition, Missisauga Formation, offshore Nova Scotia, and its correlation with shelf margin and slope strata

Abstract

Abstract A 100 m thick, more than 20 km wide upward-fining succession at the top of the Lower Cretaceous Upper Member of the Missisauga Formation was investigated in the Panuke Field, offshore Nova Scotia, using core, well logs and 3-D seismic data. The succession consists of 50 m of dune cross-stratified sandstone overlain by 50 m of tide-influenced heterolithic strata, which in turn is overlain by 150 m of mudstone of the Naskapi Member of the Logan Canyon Formation. The succession is interpreted to be a fluvial–marine transition formed during a long-term (3rd order) relative sea-level rise. The two main Panuke reservoirs are thin (<5 m) sheet-like sandstones at the Missisauga–Naskapi contact interpreted to be remnants of a wave-formed barrier system. In seismic data, the Upper Member of the Missisauga Formation correlates basinward with progradational shelf-margin reflections, suggesting that the sheet-like fluvial sandstone at the base of the upward-fining succession transferred sediment, and possibly sand, to the continental slope.