Hugenholtz, Chris H.Gough, Tyler Robert2019-04-252019-04-252019-04-25Gough, T. R. (2019). Megaripple Stripes (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.http://hdl.handle.net/1880/110217This thesis incorporates field measurements, satellite imagery, and numerical modelling to explain the formation and evolution of a poorly-understood and relatively undocumented longitudinal aeolian bedform pattern. The pattern consists of alternating streamwise corridors of megaripples separated by corridors containing smaller bedforms. This pattern, referred to herein as megaripple stripes, is observed at sites on Earth and Mars. Measurements from satellite imagery indicate a strong positive relation between the crosswind and downwind wavelengths of megaripple corridors. Field measurements of stripe morphology and grain size indicate a consistent pattern whereby the surface texture of the megaripple corridors is coarser than the intervening corridors of smaller bedforms. The amplitude and wavelength of features in the megaripple corridors are larger than the features in the smaller bedform corridors. The three-dimensional morphology and sediment sorting pattern of megaripple stripes was reproduced in a numerical model that incorporated two aeolian transport species: saltons and reptons. Simulations suggest striped pattern development is a self-organizing process resulting from grain size and topographic feedbacks that are sensitive to the bulk concentration and erosion probability of reptons. In the simulations, regular megaripples emerge from a high bulk concentration of reptons and impact ripples develop from a very low bulk concentration of reptons. Megaripple stripes emerge when the bulk concentration is intermediate between megaripple and impact ripple formation. Therefore, it is hypothesized that megaripple stripes develop in unimodal transport environments with supply-limited reptons. The nature and dynamics of reptons are largely determined by the wind regime, the grain size distribution, and by the grain density distribution in some environments. Repton behaviour, spanwise transport, and other relevant aeolian processes are discussed in relation to megaripple stripes.engUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.BedformLandformAeolianEolianGeomorphologyRippleMegarippleDuneSandWindSaltationReptationGeographyGeologyPhysical Geographymaster thesis10.11575/PRISM/36402