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| Titel |
Application of Cl-36/Cl ratio for ground ice chronometry |
| VerfasserIn |
Alexander Blinov, Juerg Beer, David Gilichinsky, Lutz Schirrmeister |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250033179
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| Zusammenfassung |
| Permafrost is a unique natural system that contains several proxy records such as fossil
faunal, floral, and microbial communities and greenhouse gases. Its potential as a
palaeoenvironmental archive makes the development of an accurate permafrost chronology
an essential objective of the data interpreting. This problem has not been solved yet,
especially for early Pleistocene to late Pleistocene deposits. Recently we have examined the
ratio of the cosmogenic nuclide chlorine-36 (36Cl) to chloride (Cl-) in ground ice (ice
wedges and segregation ice) as a measure of the formation age of ground ice. The 36Cl/Cl
was measured in 32 ground ice samples of Pleistocene permafrost horizons of the
northeastern Arctic. Though the experimental results showed two orders of magnitude
variability, we have developed several local permafrost chronometry scales. General
concordance of the modeled ages with geological expectations and other chronological
estimates supports the potential power of the proposed dating method. However, the
large observed change in 36Cl/Cl ratios from higher to lower values during the
transition from Last Glacial Maximum to Holocene climatic conditions remains
unexplained. The interpretation of the measurements is made more complex by
individual differences in chemical composition, geographical location and geological
history of the samples. Further 36Cl/Cl serial measurements that are needed to refine
this dating method into a practical tool with a clear protocol will be discussed. |
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