Constraints on the late Quaternary glacial history of the Inylchek and Sary-Dzaz valleys from in situ cosmogenic Be-10 and Al-26, eastern Kyrgyz Tian Shan

Paleoclimatic constraints from regions at the confluence of major climate systems are particularly important in understanding past climate change. Using geomorphic mapping based on remote sensing and field investigations, combined with in situ cosmogenic Be-10 and Al-26 dating of boulders associated...

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Bibliographic Details
Published in:	Quaternary science reviews 2014, Vol.101, p.77
Main Authors:	Lifton, Nathaniel, Beel, Casey, Hättestrand, Clas, Kassab, Christine, Rogozhina, Irina, Heermance, Richard, Oskin, Michael, Burbank, Douglas, Blomdin, Robin, Gribenski, Natacha, Caffee, Marc, Goehring, Brent M., Heyman, Jakob, Ivanov, Mikhail, Li, Yanan, Li, Yingkui, Petrakov, Dmitry, Usubaliev, Ryskul, Codilean, Alexandru T., Chen, Yixin, Harbor, Jon, Stroeven, Arjen P.
Format:	Article
Language:	eng
Subjects:	Cosmogenic nuclides Glacial history naturgeografi Paleoglaciation Physical Geography Tian Shan
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Summary:	Paleoclimatic constraints from regions at the confluence of major climate systems are particularly important in understanding past climate change. Using geomorphic mapping based on remote sensing and field investigations, combined with in situ cosmogenic Be-10 and Al-26 dating of boulders associated with glacial landforms, we investigate the chronology of past glaciation in the Inylchek and Sary-Dzaz valleys in the eastern Kyrgyz Tian Shan, a tectonically active area with some of the highest peaks in the world outside of the Himalayas. Cosmogenic Be-10 and (26) Al exposure ages of boulders on moraines record up to five glacial advances including: Lateglacial age lateral moraine remnants and meltwater channels in the upper Inylchek Valley; Last Glacial Maximum (LGM, Marine Oxygen Isotope Stage [MIS] 2) moraines in the Sary-Dzaz Valley and in a terminal moraine complex at the west end of the Inylchek Valley, overriding older moraines; an MIS 4 or 5 moraine remnant above the Inylchek terminal moraine complex; and an older high moraine remnant down-valley from the confluence of the Inylchek and Sary-Dzaz valleys. The evidence for glacial extent in this study is consistent with a limited ice expansion hypothesis for Tian Shan glaciation. Published results from the western and central Kyrgyz Tian Shan do not show evidence for significant LGM glacier expansion, which in combination with the results presented here, indicate a spatial variation in glacier records along the Tian Shan. This may reflect either paleoclimatic gradients or the impact of local physiographic conditions on responses to regional climate change, or both.
ISSN:	0277-3791 1873-457X 1873-457X