Identifying the sequence boundary in over-and under-supplied contexts: the case of the late Pleistocene Adriatic continental margin

Even in a system whose stratal record is wellexpressed, it can be challenging to confidently differen-tiate sequence boundaries from other erosional surfacesbecause of lateral changes in stratal patterns due to vari-ations in accommodation and sediment-supply ratesand routes. Identifying a sequence boundary, as origi-nally defined by Mitchum et al. (1977), is based onobjective geometric relations. The original and standardcriteria for defining a sequence boundary include notonly the recognition and interpretation of stratal termi-nations but also an assessment of the spatial distributionof such terminations. Key geometric relations, however,are not always apparent on every single seismic lineand are commonly inferred solely from vertical sectionsfrom boreholes. Hence it is essential to correlate andmap the three-dimensional distribution and character ofpotential sequence boundaries (and any other sequence-stratigraphic surfaces) for a more confident interpreta-tion. Variations in observed geometric relations are afunction of profile location and orientation with respectto sediment-entry points and shelf-edge, as well as tospatial changes in rates of change in accommodationrelative to the rates of sediment supply (e.g., Madof etal., 2016).