Quartz optically stimulated luminescence dating of loess in Tajikistan and its paleoclimatic implications for arid Central Asia since the Lateglacial

Thick and widespread loess deposits in southern Tajikistan provide insight into the regional climatic changes in arid Central Asia (ACA) during the Quaternary. However, because of the lack of robust chronological constraints, the environmental implications of these deposits are not yet fully understood. Here, we report a detailed medium-grained quartz optically stimulated luminescence (OSL) dating analysis on a loess sequence deposited since the Lateglacial in southern Tajikistan. The single-aliquot regeneration (SAR) and standardized growth curve (SGC) methods were used for equivalent dose determination. Quartz OSL measurements showed that both the SAR and SGC methods can be used for equivalent dose determination for Tajik loess. On the basis of the obtained OSL ages, we reconstructed the dust accumulation rates and mass accumulation rates. Our results show that the dust flux continued to decline whereas the precipitation increased stepwise after the end of the Last Glacial Maximum. Changes in the dust flux and precipitation in ACA were sensitive to the gradual warming since the Lateglacial.