Ice-rich glaciolacustrine sediments near Mayo, Yukon Territory, reveal a thaw unconformity in the form of truncated ice wedges and abrupt changes in cryotexture. The unconformity has been radiocarbon dated at 8870yr BP, which is within the Holocene period of optimal climatic conditions in N Yukon and the Mackenzie Delta area reported by other workers. Analysis of the mineralogy of the sediments indicates that the material above the unconformity is enriched in minerals that are the products of a more intense weathering environment than those deeper in the profile. An average rate of upward permafrost growth in this area of 0.1-0.2mm yr-1 is calculated for the period since the climatic optimum.-from Authors
Canadian Journal of Earth Sciences
Department of Geography and Environmental Studies

Burn, C, Michel, F.A. (F. A.), & Smith, M.W. (M. W.). (1986). Stratigraphic, isotopic, and mineralogical evidence for an early Holocene thaw unconformity at Mayo, Yukon Territory. Canadian Journal of Earth Sciences, 23(6), 794–803. doi:10.1139/e86-081