Coastal and Oceanic Landforms (40. River Delta)

                                                                                                                                         Back to Coastal and Oceanic Landforms

  • River Delta formed by;
                       Deposition of the sediment at the mouth of a river.

  • River flows into;
The Ganges Delta, India
The Ganges Delta, India

  • Obtaining a more stable steeper slope.
  • Depositional processes force redistribution of deposition from areas of high deposition to areas of low deposition.
                           -examples of  avulse : the Mississippi and Ural River deltas

  • Deltas are classified to the main control on deposition.
  • which is usually either a river, waves, or tides.

                        1.wave dominated deltas.
                          Wave erosion controls the shape of the delta.
                          River mouth is deflected along the coast line.
                         Deltas of this form, such as the Nile Delta.
Ganges Delta
Ganges Delta

                   2.Erosion /tide dominated deltas.
                       Mainly submarine.
                       Prominent sand bars and ridges.
                       Produce a "dendritic" structure.
                       Differently from river- &  wave-dominated deltas
                       It is abandoned.

                  3.A Gilbert delta 
                       Formed by coarse sediments.
                      Opposed to gently-sloping muddy deltas. 
                      Mountain river depositing sediment into a freshwater lake
                      Located on coasts tidal range

Nile Delta
Nile Delta

              4.Inverted river delta. 
                 Located inside a large valley.
                 Divide into multiple branches in an inland area.
                 Only to rejoin and continue to the sea.
                 Often occur on former lake beds.
                                                      Inner Niger Delta.
                                                     Peace–Athabasca Delta . 
                                                     Okavango Delta in Botswanais.

Okavango Delta
Okavango Delta

5.Alluvial fans
Deltas are differentiated from alluvial fans.

 Deltas have a shallow slope.

Contain fine-grained sediment;
                                     sand & mud
Flow into a body of water.
Have coarse-grained sediments.

  • The most famous delta is the Nile River.
  • The Ganges/Brahmaputra  is the world's largest delta.
  •  Notable deltas include ;

Fly River                                 Cauvery                                                Niger River
Tigris-Euphrates               Rhine                                                       Po
Rhône                                     Danube                                                   Ebro
Volga                                      Lena                                                          Indus
Ayeyarwady                       Mekong                                                   Huanghe
Yangtze                                 Sacramento-San Joaquin                Mississippi
Orinoco                                 Paraná

Mississippi River Delta
Mississippi River Delta
Yellow delta
Yellow delta

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