Origin of a postglacial kettle-fill sequence near Georgetown, Ontario

Abstract

Stratigraphic relationships, radiocarbon dating, and pollen and plant macrofossil analyses establish the origin and developmental history of a kettle near Georgetown, Ontario. The early inorganic sediments contain redeposited fossils, particularly from local vegetation. Fossils in peat younger than 10 000 BP largely represent past wetland plant communities in the basin. Although the fossil record probably began about 1300 years after deglaciation of the site, an additional 1700 years passed before the dead ice block melted; only then did sedimentation and biological activity stabilize in the basin and produce an accurate fossil record of past vegetation. Truncated fossil records, illustrated further here by a pollen diagram from nearby Heart Lake, should be expected from kettle-hole deposits, and the radiocarbon ages and fossils from the earliest parts of such sequences should be interpreted with caution.