Dynamic sedimentation of Paleoproterozoic continental margin iron formation, Labrador Trough, Canada: Paleoenvironments and sequence stratigraphy

As in the Phanerozoic, unconformities, and transgressive and maximum flooding surfaces frame iron formation sequences, but with important differences. The absence of trace and body fossils as well as lack of terrestrial vegetation can make the recognition of these surfaces difficult. Transgressive surfaces can also be easily mistaken for Phanerozoic-style maximum flooding surfaces since stratigraphic condensation was restricted to inboard environments during ravinement. Outboard the accumulation of fresh precipitates increased sedimentation to produce a maximum flooding surface not usually marked by a prominent depositional hiatus. Understanding these differences is essential for establishing an accurate sequence stratigraphic framework. Such context is the backdrop for properly interpreting the sedimentology, oceanography, microbial ecology, and geochemistry of continental margin iron formations.