Late quaternary geoarchaeology of the Lauder Sandhills, Southwestern Manitoba, Canada

This dissertation presents a multi-analytic reconstruction of the late Pleistocene-Holocene history of the south-central glacial Lake Hind basin (Lauder Sandhills region), southwestern Manitoba. Data derived from plant macrofossils and microfossils (pollen, silicophytoliths, and fungal taxa) are interpreted in conjunction with lithostratigraphic descriptions. From these lines of evidence, a 10,500-year model of landscape evolution and biotic change is offered. This model is linked to the archaeological record in order to explain broad land-use patterns in southern Manitoba.; A period of drainage of the southern Hind basin prior to ∼10,400 RCYBP is reconstructed from the sedimentological record exposed at a number of cutbank sites adjacent to the Souris River. This process is linked to the final catastrophic flood emanating from glacial Lake Regina. Between ∼10,400 and 9300 RCYBP, changes in spruce pollen frequencies record climatic warming up to approximately the 17°C isotherm, interrupted by a brief and sharp cooling trend at ∼10,000 RCYBP. This cooling trend records glacial re-advance during the Emerson Phase of glacial Lake Agassiz. Folsom complex materials within the Hind basin suggest a land-use strategy which included the utilization of recently drained proglacial lake surfaces.; After ∼9300 RCYBP, but prior to ∼6700 RCYBP, fining-upward sequences in the study area record the first incision of the Souris River into the central lake basin. Shortly after 6700 RCYBP, thermophilous plant species were present in at least three communities on the edge of the Hind basin. The earliest recorded bur oak populations in the Canadian Prairies appear in the study area. At least one eolian sand sheet was deposited after 6700 RCYBP, followed by a gradually rising water table throughout at least some of the middle Holocene. Between ∼4500 and 2500 RCYBP, a mixed grass prairie ecosystem extensively colonized the Hind basin. Some time shortly after ∼2500 RCYBP a peak in fire frequency probably occurred; this trend is linked to the deliberate burning of prairie by Sonota-Besant bison hunters.