Progradation Explained

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]

Notes and References

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