Although it is widely recognized that fluvial systems can change markedly down depositional dip, the details of variability are difficult to assess and quantify in the subsurface. In this study, Klausen et al. use data from six seismic volumes to trace and quantitatively analyze heterogeneity in fluvial strata in the Snadd Formation (Triassic, offshore Norway) across several hundred km. The results suggest that much of the deltaic depositional environment is mud-rich and channel width and aspect ratios (but not thickness) diminish in size downstream of a proximal apex point close to an interpreted delta-paleovalley transition apex. The conceptual framework provided by these data may provide a large-scale process, geomorphic, and stratigraphic context for more detailed studies of parts of this and other large-scale fluvial systems in the geologic record.
Spatial and temporal changes in geometries of fluvial channel bodies from the Triassic Snadd Formation of offshore Norway by Tore Grane Klausen, Alf Eivind Ryseth, William Helland-Hansen, Robert Gawthorpe, and Inger Laursen