230Th/U Dating of Frozen Peat, Bol'shoy Lyakhovsky Island (Northern Siberia)

The chronology of Quaternary paleoenvironment and climate in northeastern Siberia is poorly understood due to a lack of reliable numerical age determinations. The best climatic archives are ice-rich permafrost sequences, which are widely distributed in northeastern Siberia. For this study, 230Th/U-a...

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Bibliographic Details
Published inQuaternary research Vol. 57; no. 2; pp. 253 - 258
Main Authors Schirrmeister, Lutz, Oezen, Deniz, Geyh, Mebus A
Format Journal Article
LanguageEnglish
Published New York, USA Cambridge University Press 01.03.2002
Elsevier Inc
Subjects
Middle Pleistocene
geochronology
permafrost
Uranium-series disequilibrium dating
thorium
Siberia
uranium
peat
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Summary:The chronology of Quaternary paleoenvironment and climate in northeastern Siberia is poorly understood due to a lack of reliable numerical age determinations. The best climatic archives are ice-rich permafrost sequences, which are widely distributed in northeastern Siberia. For this study, 230Th/U-ages were determined by thermal ionization mass spectrometry (TIMS) from frozen peat in a permafrost deposit at the southern cliff of the Bol'shoy Lyakhovsky Island (New Siberian Archipelago), west of the Zimov'e River. These yielded a Pre-Eemian “isochron”-corrected 230Th/U-age of 200,900±3400 yr. This result is reliable because permafrost deposits behave as closed systems with respect to uranium and thorium. Our findings suggest that 230Th/U dating of frozen peat in permafrost deposits is a useful tool for the reconstruction of the Middle Quaternary environment of northern Siberia and of the whole Arctic.
ISSN:0033-5894
1096-0287
DOI:10.1006/qres.2001.2306