Deltas

Fluvial-, tidal-, and wave-dominated or -influenced deltas produce distinctive coastal morphologies, as well as have diagnostic lateral and stratigraphic facies trends. The matrix of possible combinations of these parameters is evident in the resultant sedimentology and ichnology. Reworking of fluvial-derived sediments at the coastline by oceanographic processes (e.g., wave and tidal) controls the intensity, diversity, and distribution of trace fossils in deltaic environments. The ichnological characteristics of a deltaic succession can be used to infer relative importance of fluvial, tidal, or wave processes and to refine subenvironments of marine deltas. The dominant physicochemical controls on the spatial distribution of trace fossils in deltaic settings are sedimentation rate, salinity, and hydrodynamic energy.