SEPM Strata

coastal plain and/or delta plain

The coastal plain forms a belt of mixed continental (alluvial, estuarine and aeolian) and marine (chenier, barrier island, tidal delta and deltaic) sediments that flank the sea. The difference between fluvial and other continental sediment systems and those that accumulate in the coastal plain is that the latter contain evidence of incursions of the sea, often as marine shales. The difference between the coastal plain and marine shelf is that the coastal plain, in addition to marine sediments contains continental sediments too! A confusing characteristic of coastal plain sediments is their often intense reworking by alluvial, estuarine and tidal channels which can leave a sedimentary record that appears to contain no evidence of incursions by the sea!

Most the sediments above sea level on this diagram acumulated in the coastal plain!

A large proportion if the stacked mixed marine and continental coastal sediments are coastal plain sediments. These coastal plain sediments often form the parasequences whose stacking character are interpreted to determine whether a coast is prograding, agrading or being transgressed.

In north Australia the south east coast of Gulf of Carpentaria provides a classic example of a modern coastal plain while the Pennsylvanian of Kentucky has many ancient examples!

Useful References
Bates, C. C., 1953, "Rational theory of delta formation": Bulletin American Association of Petroleum Geologists, v. 37, p. 2119-2162
Orton, G.J., and H.G. Reading (1993): "Variability of deltaic process in terms of sediment supply, with particular emphasis on grain size": Sedimentology, vol. 40, p. 475-512.
Van Wagoner, John C., R. T. Beaubouef, D. C. J. D. Hoyal, P. A. Dunn, N. L. Adair, V. Abreu, D. Li, R. W. Wellner, D. N. Awwiller, and T. Sun., 2003, "Energy Dissipation and the Fundamental Shape of Siliciclastic Sedimentary Bodies"., Abstract AAPG/SEPM: Siliciclastic sequence stratigraphy - Going Beyond parasequences; Technical Program AAPG Annual Meeting 2003