Ripple morphology in a sand/mud environment: Guyana, South America.

Ripples formed under oscillatory flows in a field setting are examined to construct a simple and accurate method of predicting ripple wavelength in a sand/mud environment. The variables that determine ripple wavelength are very complex, and at least four nondimensional parameters are important. For practical purposes the ripple wavelength normalized by the water semi-excursion (half the orbital diameter) is well determined by the mobility number and the normalized orbital diameter. Ripples with wavelengths proportional to grain size and independent of orbital diameter (anorbital ripples) were predominant in this investigation (60%). Wavelengths dependent on both orbital diameter and grain size (suborbital ripples) constituted the remaining ripples observed. Relating normalized ripple wavelength to the mobility number shows a strong correlation (r$\sp2$ = 0.7049). However, the normalized ripple wavelength is best explained by the normalized orbital diameter (r$\sp2$ = 0.7936). Equations derived by other workers to predict ripple wavelength in quartz sand were only moderately successful with fine grain sediments. Therefore, a set of expressions were developed based on the mobility number and the orbital diameter. The derived semi-empirical formulae provide a more accurate method of predicting ripple wavelength for a large set of data from a sand/mud environment.Dept. of Geography. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1996 .C87. Source: Masters Abstracts International, Volume: 37-01, page: 0217. Adviser: A. S. Trenhaile. Thesis (M.A.)--University of Windsor (Canada), 1996