Research paper Holocene moist period recorded by the chronostratigraphy of a lake sedimentary sequence from Lake Tangra Yumco on the south Tibetan Plateau Hao Long a, b, c, * , ZhongPing Lai a , Peter Frenzel d , Markus Fuchs e , Torsten Haberzettl f a Luminescence Dating Group, Key Laboratory of Salt Lake Resources and Chemistry, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, 18 Xinning Road, Xining 810008, China b Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China c Graduate University of Chinese Academy of Sciences, Beijing 100049, China d Institute of Geosciences, Friedrich-Schiller-University Jena, 07749 Jena, Germany e Department of Geography, Justus-Liebig-University Giessen, 35390 Giessen, Germany f Institute of Geography, Friedrich-Schiller-University Jena, 07743 Jena, Germany article info Article history: Received 10 October 2011 Received in revised form 17 November 2011 Accepted 19 November 2011 Available online 28 November 2011 Keywords: OSL dating Radiocarbon dating Lake sediments Tibetan Plateau Holocene climate change abstract Palaeolimnological studies together with geomorphological investigations of exposed lacustrine sections on the Tibetan Plateau provided valuable palaeoclimate records. Radiocarbon dating is the most commonly used method for establishing chronologies of lake sediments. However, 14 C dating of such sediments could be problematic due to the lack of organic matter or a reservoir effect, which commonly appears in radiocarbon ages of lacustrine sediments from the Tibetan Plateau. OSL dating is an alternative for dating the lake sediments and also provides the opportunity to independently test radiocarbon chronologies. The current study tries to compare OSL and 14 C dating results in order to evaluate the reservoir effect of 14 C dating, and then based on quartz OSL dating and stratigraphic analysis, to construct the chronostratigraphy of a lacustrine sedimentary sequence (TYC section), an offshore profile from Tangra Yumco lake on the southern Tibetan Plateau. Results suggest that: (1) it is possible to obtain robust OSL age estimates for these lake sediments and the OSL ages of the three samples range from ca. 7.6 ka to ca. 2.3 ka; (2) The discrepancy between the OSL and 14 C ages is ca. 4e5 ka, which possibly results from the age overestimate of 14 C dating due to a reservoir effect in the studied lake; (3) the chronostratigraphy of TYC section and sedimentological environmental analysis show a large lake with a lake level distinctively above the present during ca. 7.6e2.7 ka indicating a wet mid-Holocene in the study area. Ó 2011 Elsevier B.V. All rights reserved. 1. Introduction The Tibetan Plateau (TP) and its surroundings have been the target of numerous Holocene climate studies in the past years. Earlier work revealed that there was a relatively wet early Holocene and an increasingly drying mid to late Holocene (Gasse et al., 1991; Kashiwaya et al., 1991; Lister et al., 1991; Van Campo and Gasse, 1993) as a result of the early Holocene insolation maximum in low latitudes of the northern hemisphere and an associated increase in monsoon strength (Berger and Loutre, 1991). In contrast, evidence from an increasing number of sites which have experi- enced a differing climate evolution in the Holocene suggests that the Holocene climate dynamics on the TP were more spatially heterogeneous (e.g. Wu et al., 2006; Mischke et al., 2008; Zhao et al., 2011). More climatic records are thus needed to better understand the pattern or spatial heterogeneities of Holocene climate changes on the TP. Palaeolimnological studies together with geomorphological/ sedimentological studies of lake shorelines/sections provided valuable palaeoclimate records on the TP (e.g. Mischke and Zhang, 2010; Daut et al., 2010). Radiocarbon dating is the most commonly used method for establishing chronologies of these lake sedi- ments. However, 14 C dating of such sediments could be problem- atic due to the lack of organic matter or a reservoir effect, which commonly appears in radiocarbon ages of lacustrine sediments from the TP (Long et al., 2011). Optically stimulated luminescence (OSL) dating is an alternative for dating the lake sediments and also provides the opportunity to independently test radiocarbon chronologies. * Corresponding author. Luminescence Dating Group, Key Laboratory of Salt Lake Resources and Chemistry, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, 18 Xinning Road, Xining 810008, China. E-mail addresses: longhao@isl.ac.cn, lzugeolh@sina.com (H. Long). Contents lists available at SciVerse ScienceDirect Quaternary Geochronology journal homepage: www.elsevier.com/locate/quageo 1871-1014/$ e see front matter Ó 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.quageo.2011.11.005 Quaternary Geochronology 10 (2012) 136e142