Published:January 01, 1980
The term “delta” was first applied by the Greek historian Herodotus in approximately 450 B.C. to the triangular alluvial deposits at the mouth of the Nile River. In broader terms, deltas can be defined as those coastal and nearshore features that have been built by riverborne sediments. Included in this definition are those sediments that have been sorted by various marine agents such as waves, currents, and tides and redeposited in the delta plain and its nearshore waters. The various physical, chemical, and biological processes that control delta development vary appreciably on a global scale, and hence the landforms in deltaic regions span nearly the entire spectrum of coastal features and include distributary channels, rivermouth bars, interdistributary bays, tidal flats, tidal ridges, beach dune complexes, swamps, marshes, and evaporite flats.
Deltaic deposits are found where a stream debouches into a receiving basin, whether the receiving basin is an ocean, inland sea, bay, estuary, or lake. Despite the various environmental contrasts, all actively prograding deltas have at least one common attribute: a river aerial and subaqueous delta sequences); and (c) the variability of delta sediments that are deposited under a wide range of depositional facies. The modern Mississippi River will be used to illustrate the first two aspects. A considerable amount of subsurface data is available, and a large number of process studies provide the basis for this portion of the course. The discussion of the variability of deltaic deposits is based on the study of a considerable variety of depositional settings that has been conducted by personnel of the Coastal Studies Institute, Louisiana State University, during the past 20 years.
Figures & Tables
Deltaic Sand Bodies
The publication features a broad treatment of the depositional aspects of deltas, including regional settings, process activity, and their role in sedimentation. Sedimentation patterns and sand distribution in models are discussed. Examples are taken from around the world and ancient analogs are offered. An emphasis is placed on the exploration for hydrocarbons in a deltaic environment.