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cyclic phenomena in deltas may originate from both autogenetic processes and allogenetic processes Autogenetic cycles are often controlled primarily by processes taking place in the sedimentary basin itself like delta lobe switching, irregular switching of delta lobes , related to the degree of sediment accumulation and the geometry of the delta complex Allogenetic cycles are caused mainly by variations external to the considered sedimentary basin such as tectonic movements, sea level variations, and climatic changes. These processes tend to generate cyclic phenomena. Cyclic sections of a greater lateral and vertical continuity are generated by allogenetic processes while autogenetic processes show limited lateral continuity and generate small scale changes.

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