Quaternary glacial chronology of the Ateaoyinake River Valley, Tianshan Mountains, China Jingdong Zhao a,b, ⁎, Shiyin Liu a , Yuanqing He a , Yougui Song c a State Key laboratory of Cryospheric Science, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou, 730000 China b Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100085 China c Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710075 China ABSTRACT ARTICLE INFO Article history: Received 1 April 2007 Accepted 20 December 2007 Available online 8 May 2008 Keywords: ESR dating Marine oxygen isotope stages (MIS) Tianshan Mountains Glacial chronology Central Asia The Ateaoyinake River originates on the southern slope of the Tumur Peak, the largest center of modern glaciation in the central Tianshan Mountains in China. Six sets of moraines and associated glacial sediments are well-preserved in the Ateaoyinake River drainage, recording a complex history of Quaternary glacial cycles and landscape evolution. Dating the landforms allow the temporal and spatial shifts of past cryosphere and climate to be determined. Dating of the tills and outwashes was undertaken with electron spin resonance (ESR) and optically stimulated luminescence (OSL). Two OSL ages date outwash and till to 7.3± 0.8 ka and 12.3±1.2 ka, respectively. The ESR ages date six sets of moraines to 3.4 ka, 14–27 ka, 40–54 ka, 55– 62 ka, 134.4 ±12.6 ka and 219.7±20.5 ka, 440.6 ±41.7 ka. If these are correct ages of deposition, they suggest that glaciers advanced during the Neoglacial and during marine oxygen isotope stages (MIS) 2, 3b, 4, 6 and 12. The MIS 3b moraine was created by a glacier nearly as large as or possibly larger than those of the “global” Last Glacial Maximum of MIS 2. The oldest till belongs to the “Qingshantou Glacial Stage”. Its single age is consistent with two published ESR ages (459.7±46 and 471.1 ka) from the Gaowangfeng till near the headwaters of the Ürümqi River in the eastern Tianshan Mountains. These dates suggest that the central and the eastern segments of the Tianshan Mountains were high enough to be glaciated by MIS 12. The geochronology of the glacial landforms in this valley is the first step towards understanding glacial and landscape evolution in this region. Furthermore, this geochronology and previously published geochronology near the headwaters of the Ürümqi River provide a temporal framework for examining the rates of landscape evolution in the glaciated regions of the Tianshan Mountains. Crown Copyright © 2008 Published by Elsevier B.V. All rights reserved. 1. Introduction Mountain glaciers are important geomorphic agents in shaping the landscapes of glaciated regions, and are responsible for carving some of the most spectacular landscapes on Earth. The landscape contains considerable information on past glacial processes in the form of moraines and other depositional landforms. In alpine areas, glaciers are widely accepted as having sustained high rates of erosion, and generally large glaciers can erode more rapidly than smaller ones, particularly in the ablation zone (Hallet et al., 1996; Brocklehurst and Whipple, 2006). In active tectonic settings, glacier-driven erosion has the potential to influence climate by increasing chemical weathering and, ultimately, lowering atmospheric concentrations of CO 2 (Raymo and Ruddiman, 1992). In addition, glaciers enhanced rates of valley incision during glaciation and isostatic rebound would cause the high crests to rise, especially, in some alpine area, where the mountain ranges have high crests and deep valleys. The changes in relief have been suggested to influence the climate through the uplift of mountain crests (Molnar and England, 1990). The characteristic glacial landforms and bedrock topography are also studied to deduce the former properties of the glaciers, and lead to a good understanding of the temporal and spatial shifts of the past glaciers. Glaciers are highly sensitive to climate change and in China are known as “the thermometer of the landmass” (Shi et al., 2000). A glacier responses to climate directly influences geomorphic processes, sediment transfer and landscape evolution. As a consequence, abundant Quaternary glacial landforms and sediments are well- preserved in many regions throughout China. Dating glacial landforms is a fundamental requirement in studying the landscape evolution of the past cryosphere. During the past several decades, dating techniques, including cosmogenic radionuclide (CRN: e.g., Finkel et al., 2003; Owen et al., 2006a,b), electron spin resonance (ESR: e.g., Zhou et al., 2002a,b; Yi et al., 2002; Zhao et al., 2006), thermoluminescence (TL: e.g., Zhang et al., 2005) and optically stimulated luminescence (OSL: e.g., Spencer and Owen, 2004), can potentially directly determine ages of the glacial sediment and landforms. These techniques have been refined and applied widely. Geomorphology 103 (2009) 276–284 ⁎ Corresponding author. State Key laboratory of Cryospheric Science, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou, 730000 China. E-mail address: jdzhao@lzb.ac.cn (J. Zhao). 0169-555X/$ – see front matter. Crown Copyright © 2008 Published by Elsevier B.V. All rights reserved. doi:10.1016/j.geomorph.2008.04.014 Contents lists available at ScienceDirect Geomorphology journal homepage: www.elsevier.com/locate/geomorph