Reply to Ives and Froese: Regarding the impact-related Younger Dryas boundary layer at Chobot site, Alberta, Canada

Abstract

Ives and Froese (1) challenge the identification of the Chobot black mat layer at the Younger Dryas (YD) boundary (YDB), claiming that no black mats have been documented in western Canada (2). To the contrary, Haynes, a lead investigator of YD-age black mats, mapped two YD-age mat sites in western Canada (figure 1 in ref. 3): one ∼200 km south of the Chobot site at Vermillion Lakes in Alberta (12,719 ± 156 cal BP) and another at the Niske site in Saskatchewan (12,748 ± 020 cal BP).