Establishing a high-resolution luminescence chronology for the Zhenbeitai sand-loess section at Yulin, North-Central China

Abstract

Sand-loess sequences in the desert-loess transition zone are sensitive terrestrial archives for recording past climatic changes and atmospheric dust activities. However, a high-resolution chronology for relative long-term sand-loess sequences is still rare. In this study, we used quartz SAR OSL and K-feldspar pIRIR (pIRIR290) methods to date a 16.8 m sand-loess sequence at Zhenbeitai in Yulin (North-Central China). The quartz is sensitive, fast component dominated but saturates at ∼150 Gy. The measured K-feldspar pIRIR290 De showed no dependency on the first IR stimulation temperature between 50 °C and 260 °C. Dose recovery results were consistent with unity up to ∼800 Gy for a test dose of approximately 30% of the equivalent dose to be measured. The resulting pIRIR290 ages are consistent with the stratigraphy up to ∼121 ka. Thus, a high-resolution chronology up to the last interglacial could be established for the Zhenbeitai sand-loess section. Derived mass accumulation rates show sedimentation rates of ∼10–80 cm/ka for the upper loess (<10 ka) and ∼15–30 cm/ka for the loess deposits between 57 and 111 ka. Interbedded sands (∼10–65 cm/ka) suggest active dunes in the Mu Us desert during ∼17–10 ka. We found a depositional hiatus of loess between ∼47 ka and 17 ka. The Zhenbeitai sand-loess sequence provides a sensitive record of regional climatic changes in this semiarid zone since last interglacial period.