Secondary dune

Secondary dunes are also sometimes referred to as “rear dunes” and “back dunes” (http://www.islandbeachnj.org/Nature/physical/dunes.html) and “grey dunes” (http://people.uncw.edu/hosier/BIE/bieclschd/present/dneslkmorph.htm). According to Davies (1980), the terms “primary dune” and “secondary dune” are generic terms with relatively specific meanings. He defined “primary dunes” as dunes derived primarily from the beach, and he identified two types, namely, free dunes with vegetation unimportant (e.g., transverse ridges) and impeded dunes with vegetation important (e.g., foredunes). Davies’ (1980, p. 157) “secondary dunes” are dunes derived from erosion of impeded primary dunes, and he documented two types, namely, (1) transgressive dunes (e.g., blowouts, parabolics, transgressive sheets) and (2) remnant dunes which are eroded remnants of vegetated primary dunes.