Progradation

In sedimentary geology and geomorphology, the term progradation refers to the growth of a river delta farther out into the sea over time. This occurs when the volume of incoming sediment is greater than the volume of the delta that is lost through subsidence, sea-level rise, or erosion.^[1]

Progradation can be caused by:

• Periods of sea-level fall which result in marine regression. This can occur during major continental glaciations within ice ages,^[2] be caused by changes in the rates of seafloor spreading that affects the volume of the ocean basins,^[3] or tectonic effects on the regional mantle density structure that can change the geoid elevation.^[4]
• Extremely high sediment input, such as by the Huang He (Yellow River) in China, which drains the Loess plateau,^[5] or from high sediment loads in proglacial rivers.^[6]

See also

• Retrogradation – Movement of the front of a river delta inland over time
• Aggradation – Increase in land elevation due to the deposition of sediment
• Marine transgression – Geologic event in which sea level rises relative to the land
• Sedimentology – Study of natural sediments and their formation processes
• Stratigraphy – Study of rock layers and their formation
• Sequence stratigraphy – Study and analysis of groups of sedimentary deposits
• Sediment transport – Movement of solid particles, typically by gravity and fluid entrainment

References

1. Jackson, Julia A., ed. (1997). "progradation". Glossary of geology (Fourth ed.). Alexandria, Virginia: American Geological Institute. ISBN 0922152349.
2. Schofield, J. C. (March 1975). "Sea-level fluctuations cause periodic, post-glacial progradation, South Kaipara Barrier, North Island, New Zealand". New Zealand Journal of Geology and Geophysics. 18 (2): 295–316. doi:10.1080/00288306.1975.10418201.
3. Embry, Ashton F. (1988). "Triassic sea-level changes: Evidence from the Canadian Arctic Archipelago". Sea-level changes : an integrated approach. Tulsa, Okla.: Society of Economic Paleontologists and Mineralogists. ISBN 0918985749. Retrieved 23 May 2022.
4. Stoker, Martyn S.; Holford, Simon P.; Hillis, Richard R.; Green, Paul F.; Duddy, Ian R. (July 2010). "Cenozoic post-rift sedimentation off northwest Britain: Recording the detritus of episodic uplift on a passive continental margin" (PDF). Geology. 38 (7): 595–598. Bibcode:2010Geo....38..595S. doi:10.1130/G30881.1.
5. Saito, Yoshiki; Wei, Helong; Zhou, Yongqing; Nishimura, Akira; Sato, Yoshio; Yokota, Setsuya (August 2000). "Delta progradation and chenier formation in the Huanghe (Yellow River) delta, China". Journal of Asian Earth Sciences. 18 (4): 489–497. Bibcode:2000JAESc..18..489S. doi:10.1016/S1367-9120(99)00080-2.
6. Nemec, W.; LφNNE, Ida; Blikra, Lars H. (16 January 2008). "The Kregnes moraine in Gauldalen, west-central Norway: anatomy of a Younger Dryas proglacial delta in a palaeofjord basin*". Boreas. 28 (4): 454–476. doi:10.1111/j.1502-3885.1999.tb00234.x. S2CID 128823562.