Quaternary glacial chronology of the Ateaoyinake River Valley, Tianshan Mountains, China

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, 5562 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 Urumqi 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 Urumqi River provide a temporal framework for examining the rates of landscape evolution in the glaciated regions of the Tianshan Mountains. Crown Copyright (C) 2008 Published by Elsevier B.V. All rights reserved.