Codes and data for "Evaluating alluvial stratigraphic response to cyclic and non-cyclic upstream forcing through process-based alluvial architecture modelling".
datasetposted on 08.04.2020, 00:00 by Youwei WANG, J.E.A. (Joep) Storms, Allard Martinius, D. (Derek) Karssenberg, Hemmo A Abels
With this dataset generated using the method by Karssenberg and Bridge (2008), we are able to evaluate the impact of cyclic and non-cyclic upstream forcing on alluvial stratigraphy through a process-based alluvial architecture model. We find cyclic alluvial stratigraphic patterns to occur when there is cyclicity in the ratio of sediment supply over water discharge (Qs/Qw ratio), in the precondition that the allogenic forcing has sufficiently large amplitudes and long, but not very long, wavelengths, depending on inherent properties of the modelled basin (e.g. basin subsidence, size, slope, etc). Each alluvial stratigraphic cycle consists of two phases: an aggradation phase characterized by rapid sedimentation due to frequent channel shifting and a non-deposition phase characterized by channel belt stability and, depending on Qs/Qw amplitudes, incision. Larger Qs/Qw ratio amplitudes contribute to weaker downstream signal shredding by stochastic components in the model. Floodplain topographic differences are found to be compensated by autogenic dynamics at certain compensational time scales in fully autogenic runs, while the presence of allogenic forcing clearly impacts the compensational stacking patterns.