J. LeFournier, Gerald M. Friedman; Rate of Lateral Migration of Adjoining Sea-Marginal Sedimentary Environments Shown by Historical Records, Authie Bay, France. Geology ; 2 (10): 497–498. doi: https://doi.org/10.1130/0091-7613(1974)2<497:ROLMOA>2.0.CO;2
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This study documents the rate at which lateral migration of adjoining coastal sedimentary environments (spit, bay bottom, tidal marsh) has built a vertical succession of continuous, superimposed, horizontal layers. Thus, the vertical layers in this succession resulted from lateral rather than vertical sedimentation. The average rate of migration is 1 km/100 yr based on the locations of retaining dikes built at known dates as far back as 1597. The presumed location (beyond the oldest retaining dike) of the shore of the bay in early medieval times extends the record even further.