Environmental changes in Hunshandake (Otindag) sandy land revealed by optical dating and multi-proxy study of dune sands

• Sand and loam soils from Hunshandake desert was studied by OSL dating.
• Cool/dry climate was recorded from sand deposits before 7 ka ago.
• Warm/humid climate was recorded from loam soil in age of 7–4 ka ago.

A stabilized sand dune from the southern Hunshandake (Otindag) sandy land in northeastern China was studied for reconstructing past environmental changes by optically stimulated luminescence (OSL) dating, magnetic susceptibility and particle size analysis. The OSL dating results indicate that the sandy deposits at the bottom of the section formed at ∼11.8 ka ago, corresponding to low magnetic susceptibility and low fractions of fine particles (<63 μm). The variations of the two climate proxies suggest that the region was mainly influenced by arid climate. Above the bottom sand layer, there are loamy soils, which formed between ∼6.2 and ∼4.3 ka ago. The soils have relatively higher magnetic susceptibility and finer grain size than the bottom sands. The climate of this period was relatively warm and humid, dominated by enhanced summer monsoon. During the late Holocene (from ∼4 ka to present), Hunshandake was dominated by semi-humid to arid climate, as indicated by the aeolian sand beds and interbedded weak sandy soils.