High resolution OSL and post-IR IRSL dating of the last interglacial-glacial cycle at the Sanbahuo loess site (northeastern China)

Northeastern China is located in the East Asian monsoon region; it is sensitive to both high and low latitude global climate systems. Loess deposits in the region have considerable potential as sensitive archives of past climate changes. However, research into loess deposition and climate change in this region is restricted by the lack of independent age control. In this study, coarse-grained quartz SAR OSL and K-feldspar post-IR infrared (IR) stimulated luminescence (post-IR IRSL; pIRIR(290)) methods have been used to date the Sanbahuo loess site in northeastern China. The quartz OSL characteristics are satisfactory. The measured pIRIR(290) D-e's do not vary significantly with IR stimulation temperatures between 50 degrees C and 260 degrees C; a first IR stimulation temperature of 200 degrees C was adopted. Dose recovery tests were performed by adding different laboratory doses to both laboratory bleached (300 h SOL2) samples and natural samples; the results are satisfactory up to similar to 800 Gy. Resulting quartz OSL and feldspar pIRIR(290) ages are in good agreement at least back to similar to 44 ka; beyond this feldspar pIRIR(290) ages are older. The feldspar ages are consistent with the expected age of the S1 palaeosol (MIS 5). There appears to have been a period of fast loess deposition at similar to 62 ka, perhaps indicative of winter monsoon intensification with a very cold and dry climate that lead to a serious desertification of dunefields in northeastern China. (C) 2015 Elsevier B.V. All rights reserved.