Climate changes in the Hexi Corridor, western China over the past 13.3 ka

Abstract

The changing position of the northern boundary of the East Asian summer monsoon (EASM) on different timescales is important for a better understanding of future environmental changes at the edge of this monsoon's influence. Here, we have reconstructed climate changes in the central Hexi Corridor, located at the monsoon-westerlies transition zone of western China, over the past 13.3 ka. Our element data from a loess record suggest a wetting trend through the Holocene, which is different from the climate pattern observed in areas influenced by the monsoon, but consistent with sites influenced by westerlies. Comparisons indicate that the average location of EASM northern boundary in northwestern China during the early to middle Holocene was ∼300 km further northwest than today. Our Zr/Rb and grain size abundance data suggest a significant 500-year periodicity in the intensity of the East Asian Winter Monsoon (EAWM), which most likely originated from AO/NAO changes linked to solar output cycles.