When the rate of water discharge and lobe progradation are sufficiently high, a river can form a deltaic lobe. A single deltaic lobe includes a network of shallow channels called distributaries that make up a distributary network that branches off from the mainstream of the river. These networks can be the blueprint for a future progradational deltaic lobe when the initial deltaic lobe is abandonedDelta. (2016, October 10). In National Geographic Society. URL As the deltaic lobe progresses, heavier and coarser sediments settle first. As heavier sediments are deposited at the top if the deltaic lobe, smaller and finer sediments get deposited out creating the beginning of a deltaic fan. When the alluvium, the smallest sediment carried by the deltaic lobe, is deposited and new land is formed, the resulting formation is considered a delta. David E. Frazier. “Recent Deltaic Deposits of Mississippi River: Their Development and Chronology: ABSTRACT.” AAPG Bulletin, vol. 51, 1967, doi:10.1306/5d25c219-16c1-11d7-8645000102c1865d. Lobes are important in forming river deltas over time by amalgamation of channel avulsions.Moodie, Andrew J., et al. “Modeling Deltaic Lobe‐Building Cycles and Channel Avulsions for the Yellow River Delta, China.” Journal of Geophysical Research: Earth Surface, vol. 124, no. 11, 2019, pp. 2438–2462., doi:10.1029/2019jf005220. When a lobe is prograded the frequency of avulsion decreases, and the avulsion length increases relative to a non progradational deltaic lobe. As the deltaic lobe progrades the channel bed gradient is lowered, resulting in a sedimentary push upstream. This shifts the location of the avulsion forwards creating a completed deltaic lobe on which overlies a Delta.David E. Frazier. “Recent Deltaic Deposits of Mississippi River: Their Development and Chronology: ABSTRACT.” AAPG Bulletin, vol. 51, 1967, doi:10.1306/5d25c219-16c1-11d7-8645000102c1865d. Lobe formation is determined by a relationship between water discharge and lobe progradation. A model must take into account both factors in able to accurately predict avulsion timing and location. Moodie, Andrew J., et al. “Modeling Deltaic Lobe‐Building Cycles and Channel Avulsions for the Yellow River Delta, China.” Journal of Geophysical Research: Earth Surface, vol. 124, no. 11, 2019, pp. 2438–2462., doi:10.1029/2019jf005220. One example of a tide-dominated deltaic lobe system is the Han River delta in Korea. The Han River delta is shaped by its tidal changes in the summer and winter as well as its shallow and steep basins. “The Tide-Dominated Han River Delta, Korea.” 2016, doi:10.1016/c2013-0-15362-7. Gilbert deltaic lobes Gilbert deltaic lobes are defined by their movement of coarse-grained materials, relatively large sizes, and steep slopes into basins.Chavarrías, Víctor, et al. “A Sand‐Gravel Gilbert Delta Subject to Base Level Change.” Journal of Geophysical Research: Earth Surface, vol. 123, no. 5, 2018, pp. 1160–1179., doi:10.1029/2017jf004428. This rise in level commonly results in intensified aggradation and eventual decrease in topset slope .Chavarrías, Víctor, et al. “A Sand‐Gravel Gilbert Delta Subject to Base Level Change.” Journal of Geophysical Research: Earth Surface, vol. 123, no. 5, 2018, pp. 1160–1179., doi:10.1029/2017jf004428 . The most well documented example of gilbert deltaic lobes are at the gilbert delta of Lake Bonneville.“Geological and Petrophysical Characterization of the Ferron Sandstone for 3-D Simulation of a Fluvial-Deltaic Reservoir.” 2001, doi:10.34191/mp-02-6.
When the rate of water discharge and lobe progradation are sufficiently high, a river can form a deltaic lobe. A single deltaic lobe includes a network of shallow channels called distributaries that make up a distributary network that branches off from the mainstream of the river. These networks can be the blueprint for a future progradational deltaic lobe when the initial deltaic lobe is abandonedDelta. (2016, October 10). In National Geographic Society. URL As the deltaic lobe progresses, heavier and coarser sediments settle first. As heavier sediments are deposited at the top if the deltaic lobe, smaller and finer sediments get deposited out creating the beginning of a deltaic fan. When the alluvium, the smallest sediment carried by the deltaic lobe, is deposited and new land is formed, the resulting formation is considered a delta. Lobes are important in forming river deltas over time by amalgamation of channel avulsions.Moodie, Andrew J., et al. “Modeling Deltaic Lobe‐Building Cycles and Channel Avulsions for the Yellow River Delta, China.” Journal of Geophysical Research: Earth Surface, vol. 124, no. 11, 2019, pp. 2438–2462., doi:10.1029/2019jf005220. When a lobe is prograded the frequency of avulsion decreases, and the avulsion length increases relative to a non progradational deltaic lobe. As the deltaic lobe progrades the channel bed gradient is lowered, resulting in a sedimentary push upstream. This shifts the location of the avulsion forwards creating a completed deltaic lobe on which overlies a Delta.David E. Frazier. “Recent Deltaic Deposits of Mississippi River: Their Development and Chronology: ABSTRACT.” AAPG Bulletin, vol. 51, 1967, doi:10.1306/5d25c219-16c1-11d7-8645000102c1865d. Lobe formation is determined by a relationship between water discharge and lobe progradation. A model must take into account both factors in able to accurately predict avulsion timing and location. One example of a tide-dominated deltaic lobe system is the Han River delta in Korea. The Han River delta is shaped by its tidal changes in the summer and winter as well as its shallow and steep basins. Gilbert deltaic lobes Gilbert deltaic lobes are defined by their movement of coarse-grained materials, relatively large sizes, and steep slopes into basins.Chavarrías, Víctor, et al. “A Sand‐Gravel Gilbert Delta Subject to Base Level Change.” Journal of Geophysical Research: Earth Surface, vol. 123, no. 5, 2018, pp. 1160–1179., doi:10.1029/2017jf004428. This rise in level commonly results in intensified aggradation and eventual decrease in topset slope . The most well documented example of gilbert deltaic lobes are at the gilbert delta of Lake Bonneville.“Geological and Petrophysical Characterization of the Ferron Sandstone for 3-D Simulation of a Fluvial-Deltaic Reservoir.” 2001, doi:10.34191/mp-02-6.
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David E. Frazier. “Recent Deltaic Deposits of Mississippi River: Their Development and Chronology: ABSTRACT.” AAPG Bulletin, vol. 51, 1967, doi:10.1306/5d25c219-16c1-11d7-8645000102c1865d.
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Moodie, Andrew J., et al. “Modeling Deltaic Lobe‐Building Cycles and Channel Avulsions for the Yellow River Delta, China.” Journal of Geophysical Research: Earth Surface, vol. 124, no. 11, 2019, pp. 2438–2462., doi:10.1029/2019jf005220.
D
“The Tide-Dominated Han River Delta, Korea.” 2016, doi:10.1016/c2013-0-15362-7.
D
.Chavarrías, Víctor, et al. “A Sand‐Gravel Gilbert Delta Subject to Base Level Change.” Journal of Geophysical Research: Earth Surface, vol. 123, no. 5, 2018, pp. 1160–1179., doi:10.1029/2017jf004428