The response of transitional pedogenic characteristics of loess in the Yunxian Basin to abrupt climatic events in the northern subtropics since the Last Glacial Maximum

The transitional pedogenic characteristics of loess deposits in the Yunxian Basin have provided solid evidence for understanding the mechanisms of dust transportation, deposition, and detailed documentation of climate instability since the Last Glacial Maximum (LGM) in the northern subtropics of China. The Heinrich Stadial 1b (HS 1b, 16.9-14.7 ka B.P.) event, Bolling/Allerod (B/A, 13.9-13 ka B.P.) period, Younger Dryas (YD, 12.9-11.7 ka B.P.) event, and an environmental event (5-4 ka B.P.) during the Holocene Optimum were imprinted by the high-resolution multi-proxy of loess-paleosol in the Yunxian Basin, China. Based on granularity and chemical analyses, the loess in the Yunxian Basin can be classified as a fine, clayey loess zone that experienced a moderate degree of chemical weathering. The mechanism forming the transitional pedogenic characteristics was explained by the dust storm frequency data (1957-2007), particle-size data, and multi-proxy records of chemical weathering extent, which was mainly caused by the moderate transport distance from the common provenance and the transitional climatic characteristics of the northern subtropical zone.