Coastal dunes with high content of rhodolith (coralline red algae) bioclasts: Pleistocene formations on Maio and São Nicolau in the Cape Verde archipelago

► Paleodunes with high calcareous content are linked to former beaches. ► Former beaches supersede geological unconformities on basement basalt. ► Among identifiable dune bioclasts, rhodolith detritus is dominant (74-96%). ► Dune content from eroded basalt is comparatively low (2-10%). ► Stoss beds record dune migration directly or indirectly related to trade winds.