Published:January 01, 1980
Interacting physical, biological, and chemical processes during the time of deposition exert significant control over the distribution, Thus modern deltas provide a fairly good sampling of the role that climate plays in controlling depositional processes. Modern deltas debouch their sediment-water discharge into a large variety of receiving basins. They range from extremely small inland settings such as the Black Sea to larger semi-interior basins such as the Mediterranean and the Gulf of Mexico and on to broad continental shelves that front major oceanic basins such as the Pacific and Atlantic. In addition, a large number debouch into narrow seaways and semi-enclosed tectonic graben structures. Marine processes are also highly variable along modern delta coasts, which range from those that have extremely low wave energy, such as the deltaic coasts of the Nile, Mississippi, and Danube Rivers, to those that have extremely high wave energy such as the Senegal and the Sao Francisco, which debouch onto continental shelves fronting the major South Atlantic stormy seas. Tidal variation also shows considerable ranges into which the deltas must prograde. Low-tide deltas such as the Mississippi, the Nile,-and the Danube contrast strongly to those deltas where tidal range can be extremely high (up to 10-15 m), such as the delta plains of the Ord River, in Western Australia, and the Ganges-Brahmaputra, in Bangladesh. Thus, although modern deltas all display common components, their size, shape, and subsurface relationships vary from delta to delta. In order to interpret and exploit efficiently ancient deltaic sequences, it is of fundamental importance to understand the mechanisms controlling the formation and distribution of deltaic sand bodies.
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.