Multi-proxy lake sediment record of prehistoric (Paleoindian–Archaic) archaeological paleoenvironments at Rice Lake, Ontario, Canada

The arrival of Paleoindian peoples in the lower Great Lakes (ca 11.5 ka cal. BP) coincided with a phase of lowstand lakes and rapid environmental change in southern Ontario. At Rice Lake, an archaeologically-rich area north of Lake Ontario, rising Early Holocene water levels inundated wetland areas exploited by Paleoindian and Archaic peoples. In order to better understand the distribution of submerged archaeological sites and the water level history of Rice Lake, a detailed multi-proxy study was conducted on two vibracores extracted from the open lake and a shallow (<4 m) lagoon adjacent to the McIntyre archaeological site (Paleoindian–Archaic-era). Cores were analyzed for particle size, thecamoebians (testate amoebae), magnetic susceptibility and presence of microdebitage (tool lithic fragments) to determine changes in water levels, lake trophic status and the location of submerged archaeological sites.The basin stratigraphy consisted of Holocene organic-rich muds (gyttja), laminated marls, and peats overlying glacial Lake Iroquois sands and clay deposits. Two erosional hiatuses indicating lowstand phases (EH-1 ca 12.5–11 ka cal. BP EH-2 ca 6–3 ka cal. BP) were identified by rapid shifts in particle size and thecamoebian abundance and assemblages. The dominant thecamoebian species in the open lake basin were Arcella vulgaris and Centropyxis constricta ‘aerophila’, indicating the trophic status of the lake has remained stable throughout the Holocene. In the McIntyre lagoon, the EH-1 lowstand was associated with a unique bog and wetland species (Bullinularia and Phryganella sp.) along with the recovery of microdebitage, indicating that Paleoindian peoples were likely exploiting wetland resources such as plants, fish and waterfowl. We show that the study of lacustrine paleoenvironments using a multi-proxy approach provides additional information for identifying areas of archaeological potential and gaining additional understanding of settlement patterns and resource procurement strategies of Paleoindian and Archaic peoples in Southern Ontario.