The Prairie Dune Archipelago

Abstract

The Prairie dune archipelago describes the widely distributed dune fields extending across the Canadian Prairie Provinces. These dune fields have a common origin, with sediment supply derived from sandy outwash deposits associated with meltwaters of receding Laurentide and Cordilleran glacial ice. Wind reworked sediments soon after deglaciation, in a time-transgressive manner from south to north. Within the boreal forests of western Canada, post-glacial dune fields are well preserved with little to no remobilization during the Holocene. In contrast, dune fields of the southern Prairies reveal palimpsest landscapes, where dunes were reworked multiple times during the Holocene and presently display complex morphologies and depositional histories. Whereas relict and partially active stabilized parabolic dunes throughout the Prairies reflect primarily non-arid conditions, evidence exists for desert-like dunes on the southern Prairies developed during the Little Ice Age, possibly under reduced moisture conditions and shorter growing seasons. Historical accounts of dune fields indicate substantively more active dune fields in previous centuries than at present, raising issues as to the extent of past disturbances, including drought, fire, trampling and grazing on the activity of sand dunes. The few dune fields with presently active areas have also witnessed significant decline in this century, with a commensurate loss of plant and animal populations associated with these unique landscapes.