S.A.Wolfe, D.J.Huntley, P.P.David, J.Ollerhead, D.J.Sauchyn and G.M.MacDonald..

Late 18^th century drought-induced sand dune activity, Great Sand Hills, Saskatchewan.

Canadian Journal of Earth Sciences, in press.

Abstract

Geomorphic evidence and optical ages from dune sands indicate that widespread dune activity occurred within the last 200 years in the Great Sand Hills region of southwestern Saskatchewan. This most recent interval of activity was initiated about AD 1800, and continued at a higher level than present for approximately 80 years. The most likely cause of dune activation was lower-than-average precipitation through the 1700s, culminating in drought in the late 1700s. The evidence for this was found in dendroclimatic records from the Cypress Hills and from the Rocky Mountain Foothills of southwestern Alberta. Dunes affected by such climatically induced regional activity require many decade to restabilize. Historical observations show that dunes in this area have been restabilizing throughout the 20thcentury. For the southern Canadian Prairies, a region with serious concerns about the implications of global warming, this study highlights the sensitivity of sand dunes to drought and cumulative moisture stress.