Palaeoglaciation of Bayan Har Shan, northeastern Tibetan Plateau: glacial geology indicates maximum extents limited to ice cap and ice field scales

Abstract

Key locations within an extensive area of the northeastern Tibetan Plateau, centred on Bayan Har Shan, have been mapped to distinguish glacial from non-glacial deposits. Prior work suggests palaeo-glaciers ranging from valley glaciers and local ice caps in the highest mountains to a regional or even plateau-scale ice sheet. New field data show that glacial deposits are abundant in high mountain areas in association with large-scale glacial landforms. In addition, glacial deposits are present in several locations outside areas with distinct glacial erosional landforms, indicating that the most extensive palaeo-glaciers had little geomorphological impact on the landscape towards their margins. The glacial geological record does indicate extensive maximum glaciation, with local ice caps covering entire elevated mountain areas. However, absence of glacial traces in intervening lowerlying plateau areas suggests that local ice caps did not merge to form a regional ice sheet on the northeastern Tibetan Plateau around Bayan Har Shan. No evidence exists for past ice sheet glaciation.

Denudation pattern across the Longriba fault system and implications for the geomorphological evolution of the eastern Tibetan margin

“…In eastern Tibet, no evidence from morphological analysis supports the presence of a wide ice sheet, at least over the late Quaternary (Heyman et al, 2009;Fu et al, 2013). However, small ice caps and glaciers are present in the main mountain ranges of the eastern plateau such as the Bayan Har (northwest of the Ruoergai basin) and the Shaluli (southeast of our study area).…”

Paleoglaciation of the Tibetan Plateau and surrounding mountains based on exposure ages and ELA depression estimates

“…Seong et al, 2007;Owen et al, 2009) as well as in currently non-glaciated low-relief mountain regions (e.g. Heyman et al, 2009;Fu et al, 2013a). Exposure dating has been applied across the plateau with most studies focusing on the mountain regions along the plateau margin.…”

Glacial geomorphology of the Shaluli Shan area, southeastern Tibetan Plateau

“…Considerable controversy surrounds past paleoglaciological reconstructions of the Tibetan Plateau that range from a plateau-wide ice sheet synchronous with northern hemisphere glaciation (Kuhle, 1988) to limited glacier and ice cap expansions with timing and extents that do not match the northern hemisphere record (e.g., Lehmkuhl & Owen, 2005;Owen et al, 2005;Rutter, 1995;Zhou, Li, Zhang, Zhao, & Cui, 2004). Although past glaciations have been reconstructed for some regions (e.g., Heyman et al, 2011;Owen et al, 2005), and the hypothesis of a plateau-wide ice sheet during the last glacial maximum has been rejected (e.g., Heyman et al, 2009;Li et al, 1991), the extent and timing of glaciation in many areas remains poorly documented.…”