Enhancement mechanisms of magnetic susceptibility in the Chinese red‐clay sequence

Little is known about the mechanisms of magnetic susceptibility (χ) enhancement for the red‐clay sequence on the Chinese Loess Plateau (CLP), in comparison to the overlying loess‐paleosol sequence. Here we present a rock magnetic study of the red‐clay sediments from the central CLP. Our results show that frequency dependence of χ (χfd = χlf − χhf, where χlf and χhf are χ measured at 470 Hz and 4700 Hz, respectively), χlf, and susceptibility of anhysteretic‐remanent‐magnetization (χARM) are linearly correlated within the red‐clay sequence. This linear correlation indicates that the pedogenic magnetic minerals of the red‐clay have a rather uniform grain size distribution as in the loess‐paleosol sequence, and the grain size is independent of the degree of pedogenesis. Nevertheless, red‐clay sediments are slightly more enriched in superparamagnetic magnetic particles than the overlying loess‐paleosol sediments as indicated by the higher slope of the regression line between χfd and χlf.