Deciphering the origin of cyclical gravel front and shoreline progradation and retrogradation in the stratigraphic record John J. Armitage1, Peter A. Burgess2, Gary J. Hampson3, and Philip A. Allen3 1Department of Earth Science, Royal Holloway, University of London, Egham, UK; Now at Institut de Physique du Globe de Paris, 1 rue Jussieu, Paris, 75005, France; e-mail:
[email protected] 2Department of Earth Science, Royal Holloway, University of London, Egham, UK 3Department of Earth Science and Engineering, Imperial College London, London, UK May 4, 2016 1 1 Abstract 2 Nearly all successions of near-shore strata exhibit cyclical movements of the shoreline, which 3 have commonly been attributed to cyclical oscillations in relative sea level (combining eustasy 4 and subsidence) or, more rarely, to cyclical variations in sediment supply. It has become accepted 5 that cyclical change in sediment delivery from source catchments may lead to cyclical movement 6 of boundaries such as the gravel front, particularly in the proximal segments of sediment routing 7 systems. In order to quantitatively assess how variations in sediment transport as a consequence 8 of change in relative sea-level and surface run-off control stratigraphic architecture, we develop a 9 simple numerical model of sediment transport and explore the sensitivity of moving boundaries 10 within the sediment routing system to change in upstream (sediment flux, precipitation rate) and 11 downstream (sea level) controls. We find that downstream controls impact the shoreline and sand 12 front, while the upstream controls can impact the whole system depending on the amplitude of 13 change in sediment flux and precipitation rate.