Lack of correlation between paleoprecipitation and magnetic susceptibility of Chinese loess/paleosol sequences

Abstract

We have conducted a detailed mineral magnetic study of loess unit 8 (L8) and paleosol unit 8 (S8) from three localities (Jingbian, Yichuan, and Duanjiapo) along a N-S transect in the Chinese loess plateau. As expected, the lowfield magnetic susceptibility (χ) has higher values in S8 and lower values in L8. Similarly, superparamagnetic particle concentrations increase in S8 with increasingly humid climates along the N-S transect, which suggests that pedogenic magnetic enhancement is related to climate. However, in S8 at Duanjiapo, χ is so low that there is no correlation between χ and the degree of pedogenesis in this loess-paleosol cycle. It therefore appears that χ is not consistently the most suitable indicator of paleoclimate in Chinese loess-paleosol sequences. Our results indicate that there are complexities in the mineral magnetic response to pedogenesis, which could invalidate interpretation of the χ record of Chinese loess-paleosol sequences in terms of paleoprecipitation.