Chronology of Taylor Glacier Advances in Arena Valley, Antarctica, Using in Situ Cosmogenic 3 He and 10 Be

• Published in: Quaternary Research
• Main Authors: Brook, Edward J., Kurz, Mark D., Ackert, Robert P., Denton, George H., Brown, Erik T., Raisbeck, Grant M., Yiou, Francoise
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 1993
• Subjects: Antarctic; Victoria Land; East Antarctic Ice Sheet; Taylor Glacier; Arena Valley; Antarc*; Antarctica; Ice Sheet
• Online Access: http://dx.doi.org/10.1006/qres.1993.1002; http://api.elsevier.com/content/article/PII:S0033589483710021?httpAccept=text/xml; http://api.elsevier.com/content/article/PII:S0033589483710021?httpAccept=text/plain; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0033589400034116

Abstract In situ produced cosmogenic nuclides provide a new technique for constraining exposure ages of glacial deposits. In situ 3 He and 10 Be in quartz sandstone boulders from Arena Valley, southern Victoria Land, Antarctica, provide chronological constraints for a sequence of moraines ("Taylor II-IVb" moraines) related to expansions of Taylor Glacier and the East Antarctic Ice Sheet. Mean 3 He ages are 113,000 ± 45,000 yr, 208,000 ± 67,000 yr, 335,000 ± 187,000 yr, and 1.2 ± 0.2 myr, for Taylor II,III,IVa, and IVb moraines, respectively (mean ± 1σ). Corresponding mean 10 Be ages for Taylor II and IVb moraines are 117,000 ± 51,000 yr and 2.1 ± 0.1 myr. For the older deposits the 3 He ages are probably lower limits due to diffusive loss. Although the exposure ages appear consistent with the few previous age estimates, particularly with an isotope stage 5 age for Taylor II, each moraine exhibits a broad age distribution. The distribution probably results from a variety of factors, which may include prior exposure to cosmic rays, 3 He loss, erosion, postdepositional boulder movement, and radiogenic production of 3 He. Nonetheless, the exposure ages provide direct chronological constraints for the moraine sequence, and suggest a maximum thickening of Taylor Glacier relative to the present ice surface of ∼500 m since the late Pliocene-early Pleistocene.