Palaeoenvironmental reconstruction at an oxbow lake situated at the lower Nottawasaga River, southern Ontario, Canada

Abstract

The purpose of this investigation at the lower Nottawasaga River in southern Ontario, Canada, was to reconstruct the impact of base level on fluvial stability and human occupation during the Holocene in a topographically confined section, where the river cuts through the Edenvale Moraine. Three cores were extracted from an oxbow lake (Doran Lake) and a ground-penetrating radar survey was executed in its vicinity to study wider subsurface alluvial architecture. Radiocarbon dating suggests that the Nottawasaga River became entrenched in the Edenvale Moraine early in the Holocene, with base-level lowering in the Lake Huron basin, and that Doran Lake formed towards the middle Holocene as a meander cutoff when water levels in the Lake Huron basin increased, leading to a period of fluvial instability, enhanced flow and floodplain aggradation. Fluctuating lake levels would have affected human settlement as well as the preservation and visibility of archaeological remains predominantly through vertical accretion.