Glacial Lake Arkona – Whittlesey transition near Leamington, Ontario: geology, plant, and muskox fossils

• Published in: Canadian Journal of Earth Sciences
• Main Authors: Morris, T. F., McAndrews, J. H., Seymour, K. L.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1993
• Subjects: General Earth and Planetary Sciences; Glacial Lake; muskox; Tundra
• Online Access: http://dx.doi.org/10.1139/e93-210; http://www.nrcresearchpress.com/doi/pdf/10.1139/e93-210

Proglacial subaquatic fans between Leamington and Colchester, Essex County, Ontario, were deposited in glacial Lake Maumee at the end of the Port Bruce Stade by ice retreating northward. Some fans were buried by till and glaciolacustrine materials. One fan surface, northwest of Leamington, was only modified by lake current that transgressed and regressed over it. An aggregate excavation (Bondi site) exists within the surface of this fan. We describe the sedimentology of the site that provides evidence for fan and overlying bar deposits.Lake levels fell to the levels of lakes Arkona (216 m) and Ypsilanti (122 m) following the deposition of the fans. Large terrestrial areas supported plants and animals. Their presence is recorded at the Bondi site by a single bone and several organic mats recovered from the fan and bar sediment contact at two separate exposures. Radiocarbon dates on the bone of 13 410 ± 100 BP (TO-1803), organic material dates of 13 225 ± 200 BP (BGS-1404) and 13 150 ± 100 BP (WE-01-89), the altitude. (209 m), and the sedimentological setting indicate deposition during the Lake Arkona (216 m) – Lake Whittlesey (226 m) transition period.The pollen and plant macrofossil assemblages recovered from the organic material indicate a forest–tundra environment, with a mean July temperature of 14 °C. This interpretation fits well with the bone identified as cf. Euceratherium sp., a shrubox. The discovery of cf. Euceratherium sp. is surprising, as its previous range was south and west of this site. The organic material was subsequently buried by the formation of a bar as water levels rose within the Lake Erie basin and transgressed the site.