Longitudinal Dunes (or Linear Dunes)

Abstract

Linear dune, linear ridge, and sand ridge. The terms seif and linear and longitudinal are sometimes used interchangeably, although longitudinal dune is a morphodynamic term, compared to linear (or seif) dune, which are morphologic-descriptive terms that can be used even when formative processes are not known (Rubin and Hunter 1985). The term “linear dune” refers to the group of straight and sinuous longitudinal dunes. However, straight longitudinal dunes are generally referred to as “linear dunes.” Less frequently, they are referred to as “linear ridges” (not recommended) or “sand ridges” to distinguish them from sinuous seif dunes. The term “Linear ridge types (various origins)” may also refer to any elongated, straight, positive landform without genetic or compositional implications. In this entry, we refer to the linear/curvilinear (non-sinuous) variant of linear dunes as “straight longitudinal dunes.” Moreover, transverse dunes may be also linear, but never longitudinal.