Th/U dating of frozen peat, Bol'shoy Lyakhovsky Island (northern Siberia)

• Published in: Quaternary Research
• Main Authors: Schirrmeister, L, Oezen, D, Geyh, MA
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Cambridge University Press (CUP) 2002
• Subjects: Ice; permafrost; Siberia
• Online Access: https://epic.awi.de/id/eprint/57874/; https://epic.awi.de/id/eprint/57874/1/Schirrmeister_2002_QR.pdf; https://hdl.handle.net/10013/epic.e79a4765-cfba-400f-ac65-4f29c930baae

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. © 2002 University of Washington.