MILES OF BURNING SAND: RECONSTRUCTING DUNE FIELD ACTIVITY 150 YEARS AFTER THE PALLISER EXPEDITION

In July of 1859, Captain John Palliser traversed the Middle Sand Hills of southwestern Alberta, Canada, as part of a four-year expedition assessing settlement opportunities of British North America. Palliser found the sand hills in a highly active state, and his diary reveals the great challenges he and his men faced while travelling through “… miles of burning sand”. Today, this dune field is almost entirely stabilized by vegetation, with only a few minor blowouts totalling about 10 hectares in area. Using historical airphotos of active sand areas and luminescence dating (IRSL on feldspar) of stabilized dunes, we reconstruct the landscape encountered by Palliser and show that it was at least an order-of-magnitude more active than today. We further define two periods of rapid dune stabilization after the 1880s and the mid-1930s, corresponding to the onset of comparatively moist conditions following drought. Whereas previous researchers have confirmed that Palliser travelled through the prairies during conditions of drought, we suggest Palliser’s observations of the sand hills significantly influenced his perception of the southern prairies as a region where “there is no timber, the soil is sandy, with little or no admixture of earthy material and the pasture is inferior”, and motivated his famous declaration that the area would be “forever comparatively useless”. We further suggest that a drier, colder and possibly windier climate resulted in desert-like conditions in sand hills prior to the 1800s and that climate, coupled with disturbance suppression, has been the main driver of dune field stabilization across the Canadian prairies.