TY - JOUR

T1 - Effect of Bed Clay on Surface Water-Wave Reconstruction from Ripples

AU - Malarkey, Jonathan

AU - Pollard, Ellen

AU - Fernández, Roberto

AU - Xuxu, Wu

AU - Baas, Jaco

AU - Parsons, Daniel

PY - 2024/12/28

Y1 - 2024/12/28

N2 - Wave ripples can provide valuable information on their formative hydrodynamic conditions in past subaqueous environments by inverting dimension predictors. However, these inversions do not usually take the mixed non-cohesive/cohesive nature of sediment beds into account. Recent experiments involving sand-kaolinite mixtures have demonstrated that wave-ripple dimensions and the threshold of motion are affected by bed clay content. Here, a clean-sand method to determine wave climate from orbital ripple wavelength has been adapted to include the effect of clay and a consistent shear-stress threshold parameterisation. From present-day examples with known wave conditions, the results show that the largest clay effect occurs for coarse sand with median grain diameters over 0.45 mm. For a 7.4% volumetric clay concentration, the range of possible water-surface wavelengths and water depths can be reduced significantly, by factors of three and four compared to clean sand, indicating that neglecting clay when present will underestimate the wave climate. [Abstract copyright: © 2024. The Author(s).]

AB - Wave ripples can provide valuable information on their formative hydrodynamic conditions in past subaqueous environments by inverting dimension predictors. However, these inversions do not usually take the mixed non-cohesive/cohesive nature of sediment beds into account. Recent experiments involving sand-kaolinite mixtures have demonstrated that wave-ripple dimensions and the threshold of motion are affected by bed clay content. Here, a clean-sand method to determine wave climate from orbital ripple wavelength has been adapted to include the effect of clay and a consistent shear-stress threshold parameterisation. From present-day examples with known wave conditions, the results show that the largest clay effect occurs for coarse sand with median grain diameters over 0.45 mm. For a 7.4% volumetric clay concentration, the range of possible water-surface wavelengths and water depths can be reduced significantly, by factors of three and four compared to clean sand, indicating that neglecting clay when present will underestimate the wave climate. [Abstract copyright: © 2024. The Author(s).]

KW - Geology

KW - Oceanography

KW - Sand-clay mixtures

KW - Sediment transport

KW - Wave reconstruction

KW - Wave ripples

U2 - 10.1038/s41598-024-78821-5

DO - 10.1038/s41598-024-78821-5

M3 - Article

VL - 14

SP - 30688

JO - Scientific Reports

JF - Scientific Reports

SN - 2045-2322

IS - 1

M1 - 30688

ER -