US EPA

1287790 

Book/Book Chapter 

Ratio of (super 36) Cl/Cl in ground ice of East Siberia and its application for chronometry 

Blinov, A; Alfimov, V; Beer, J; Gilichinsky, D; Schirrmeister, L; Kholodov, A; Nikolskiy, P; Opel, T; Tikhomirov, D; Wetterich, S 

2009 

American Geophysical Union and The Geochemical Society 

United States (USA) 

10 (2009) 

Abundance of the cosmogenic nuclide chlorine-36 ( (super 36) Cl) was measured together with the chloride (Cl (super -) ) concentration in different horizons of Quaternary permafrost samples collected from various types of ground ice in the northeastern part of Siberia. The (super 36) Cl/Cl in 32 samples ranged in value from 2.4X10 (super -14) to 1.4X10 (super -12) . Nonetheless, after a few extreme values were excluded, these (super 36) Cl/Cl ratios provided a local permafrost chronometry. The general concordance of the modeled ages with geological expectations and other chronological methods supports the potential power of the proposed dating method. However, the large observed change in ratios from higher to lower values during the transition from Last Glacial Maximum to Holocene climatic conditions remains unexplained. An attempt to make use of the corresponding beryllium-10 ( (super 10) Be) absolute concentrations in the same samples failed because input of (super 10) Be attached to particulate matter into permafrost is unknown. Further (super 36) Cl/Cl serial measurements of modern precipitation and fossil ground ice are needed to refine this dating method into a practical tool with a clear protocol. 

metals; chronology; Cenozoic; Asia; ice wedges; Siberia; cosmogenic elements; isotope ratios; ice; alkaline earth metals; eastern Siberia; beryllium; Cl-36; dates; exposure age; chlorine; isotopes; Be-10; halogens; age; Quaternary; radioactive isotopes; Holocene; periglacial features; permafrost; ground ice; last glacial maximum