Kansas Geological Survey, Current Research in Earth Sciences, Bulletin 241, part 1
Allostratigraphic and Sedimentologic Applications of Trace Fossils to the Study of Incised Estuarine Valleys

Fig. 32. Ichnofacies model of a transgressive system tract in an incised estuarine valley system. (A) Cross section; (B) plan view (adapted from Zaitlin et al., 1994). Boundaries of system tracts are based on definitions by Dalrymple et al. (1992). In the trangressive system tract the estuary funnel and upper estuary channels are separated. At an early stage, freshwater conditions coexist with tidal influence in the upper estuary channels, where a mixed Scoyenia-Mermia ichnofacies is present. A mixed Cruziana-Skolithos ichnofacies typifies the brackish-water estuary funnel. As transgression proceeds, brackish-water conditions reach the upper estuary channels and the mixed Cruziana-Skolithos ichnofacies migrates landward. Normal salinity waters in the estuary funnel may progressively allow the establishment of a more marine Cruziana ichnofacies.

Kansas Geological Survey
Web version March 19, 1998
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