Stratigraphic, isotopic, and mineralogical evidence for an early Holocene thaw unconformity at Mayo, Yukon Territory
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 8870 ± 200 years BP, which is within the Holocene period of optimal climatic conditions in...
| Published in: | Canadian Journal of Earth Sciences |
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| Main Authors: | , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Canadian Science Publishing
1986
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| Subjects: | |
| Online Access: | http://dx.doi.org/10.1139/e86-081 http://www.nrcresearchpress.com/doi/pdf/10.1139/e86-081 |
| Summary: | 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 8870 ± 200 years BP, which is within the Holocene period of optimal climatic conditions in northern 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. Oxygen-isotope ratios of ground ice in the sediments suggest the presence of two genetically distinct ice units above and below the unconformity. An average rate of upward permafrost growth in this area of 0.1–0.2 mm year −1 is calculated for the period since the climatic optimum. |
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