A postglacial plant macrofossil record of vegetation and climate change in southern Saskatchewan

Plant macrofossil analyses and 14C ages from a small, closed-drainage basin on The Missouri Coteau are used to reconstruct six phases of postglacial environmental change in southern Saskatchewan. Fossil remains of 41 taxa of vascular and nonvascular plants have been recognized and are illustrated. Sparse macrofossils recovered from the basal diamicton (phase 1) are likely redeposited. Abundant fossils indicate establishment of an open, white spruce forest by ca. 10 200 BP (phase 2), followed by development of a pond and replacement of the spruce forest by deciduous parkland vegetation (phase 3) that persisted until ca. 8800 BP. The pond shallowed at the end of this period. Prairie fires are evident between ca. 8800 and 7700 BP (phase 4). Water levels rose between ca. 7700 and 5800 BP, and a semipermanent prairie pond was established (phase 5). After 5800 BP, this wetland became ephemeral (phase 6) and no longer conducive for fossil preservation.