Magnetic Susceptibility of Holocene Loess‐Black Loam Sequence from Jiaodao Profile of China Before and after Citrate‐Bicarbonate‐Dithionite Extraction

Abstract

AbstractMagnetic susceptibility, anhysteretic susceptibility, frequency‐dependent susceptibility and temperature‐dependent susceptibility (TDS) before and after citrate‐bicarbonate‐dithionite (CBD) treatment were analysed on the Holocene loess–black loam sequence from Jiaodao, Shanxi province. The pedogenic magnetic grains, including maghemite and fine‐grained magnetite, can be effectively removed by CBD, and the lithogenic magnetic grains (mainly mutidomain magnetite) are nearly intact during CBD treatment. Our results suggest that the CBD technique is useful in distinguishing pedogenic contributions to the susceptibilities and that TDS can be used as a useful method for the analysis of susceptibility enhancement and pedogenesis in Chinese loess and paleosols. Thus, it could be concluded that the CBD technique provides a strong support for the pedogenic model of susceptibility enhancement and eolian origin of Chinese loess and paleosols. Especially, the combination study using CBD and TDS methods suggests that the maghemite grains produced due to pedogenesis make significant contributions to the enhanced susceptibility of loess and paleosols.