Luminescence-chronology of the loess palaeosol sequence Toshan, Northern Iran e A highly resolved climate archive for the last glacialeinterglacial cycle T. Lauer a, * , M. Frechen a , S. Vlaminck b , M. Kehl b , E. Lehndorff d , A. Shahriari e , F. Khormali c a Leibniz Institute for Applied Geophysics (LIAG), Section 3, Geochronology and Isotope Hydrology, Stilleweg 2, 30655 Hannover, Germany b Institute of Geography, University of Cologne, Albertus Magnus Platz, 50923 Cologne, Germany c Dept. of Soil Sciences, Faculty of Agriculture, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan 49138-15739, Iran d Institute of Crop Science and Resource Conservation (INRES), Soil Science and Soil Ecology, Bonn University, Nussallee 13, 53115 Bonn, Germany e Dept. of Soil Sciences, Faculty of Water and Soil, University of Zabol, Zabol, Iran article info Article history: Available online xxx Keywords: Northern Iran Caspian lowland Pleistocene Loess Luminescence dating pIRIR 290 abstract Loess-palaeosol sequences are highly resolved archives for palaeoenvironmental reconstruction and build an important link to correlate European and Central Asian loess sequences. For the loess palaeosol sequence at Toshan, Northern Iran, a luminescence-based chronological framework was established. The timing of dust accumulation and soil formation was investigated and thereby information on changes in palaeoenvironmental conditions in the region obtained. For luminescence dating, the 4e11 mm grain size fraction was used and the pIRIR 290 approach was applied to polyminerals. Tests concerning bleachability, dose recovery and anomalous fading were conducted. The results show that residual doses have only minor influence on the determination of the equivalent dose. The Eemian (MIS 5e) soil seems to be preserved but a chronological classification based on luminescence ages for this soil remains difficult. The pIRIR 290 age estimates from the lower part of the profile range from 104 ± 9 to 127 ± 8 ka. Lumi- nescence ages from the central profile-part point to an increase in dust accumulation starting around the MIS 4/MIS 3 transition. Furthermore, a chronological framework for interstadial soils was developed indicating e.g. soil formation at around 40 ka during MIS 3 and 26 ka during MIS 2. The top part of the profile was dated to about 22 ka. The age estimates show that the Toshan loess profile is a highly resolved loess record providing a valuable climate archive for the last glacialeinterglacial cycle reflecting several climatic shifts represented by dust accumulation or enhanced degrees of soil formation (stadials and interstadials). © 2015 Elsevier Ltd and INQUA. All rights reserved. 1. Introduction Loess-palaeosol sequences are sediment archives providing detailed information on Quaternary climate changes on a regional scale (e.g. Bibus et al., 2007; Markovi c et al., 2008; Buggle et al., 2009; Wacha et al., 2011). The alteration of phases of increased dust accumulation with periods of soil formation represents cli- matic shifts from cold and arid conditions to warmer and more humid conditions with increased vegetation cover and landscape stability and vice versa. The Northern Iranian loess sequences (Fig. 1) are very valuable archives due to their extraordinary thickness of up to 30 m on the foothills of the Alborz-Mountains and about 60 m in the so called Northern Iranian Loess-Plateau. Furthermore, Northern Iranian loess provides a missing link for the correlation between Central Asian and European loess archives. The Northern Iranian loess deposits have been studied by e.g. Kehl et al. (2005), Kehl (2010), Frechen et al. (2009) and Karimi et al. (2009, 2013), and the pub- lished results highlight the potential of these sediments for a detailed reconstruction of Quaternary shifts in temperature, hu- midity, wind speed and landscape evolution. Of special interest is the gradient in precipitation in the Northern Iranian loess region (e.g. Khormali and Kehl, 2011; Khormali et al., 2012) reaching from semi-arid to sub-humid climate conditions and therefore allowing * Corresponding author. E-mail address: tobias.lauer@liag-hannover.de (T. Lauer). Contents lists available at ScienceDirect Quaternary International journal homepage: www.elsevier.com/locate/quaint http://dx.doi.org/10.1016/j.quaint.2015.03.045 1040-6182/© 2015 Elsevier Ltd and INQUA. All rights reserved. Quaternary International xxx (2015) 1e10 Please cite this article inpress as: Lauer, T., et al., Luminescence-chronology of the loess palaeosol sequence Toshan, Northern Iran e A highly resolved climate archive for the last glacialeinterglacial cycle, Quaternary International (2015), http://dx.doi.org/10.1016/j.quaint.2015.03.045