Spatial and temporal reconstructions of changes in the Asian palaeomonsoon: A new mineral magnetic approach

Magnetic mineralogy of soils across the Russian Steppe: climatic dependence of pedogenic magnetite formation

“…To isolate the in situ, soil-formed magnetic signal, the pedogenic susceptibility (M ped ) was de¢ned for each soil as the maximum susceptibility value (M) of the B horizon minus the M of the parent loess. Maher et al (1994) found strong positive correlation (R 2 = 0.94) between the logarithm of pedogenic M and annual rainfall. Similarly, Han et al (1996) examined a further 63 topsoil samples across the Loess Plateau and also identi¢ed a direct (albeit polynomial) relationship between rainfall and susceptibility.…”

“…Apparent coupling between magnetism of loessic soils and rainfall was ¢rst observed for modern soils developed on the near-horizontal, homogenous parent substrates of the famous Loess Plateau region of north-central China (Maher et al, 1994;Liu et al, 1995). At the present day, this region experiences a strong gradient in rainfall, from values around 300 mm yr 31 in the west, to V550 mm yr 31 in the central Plateau and V700 mm yr 31 in the south.…”

“…The pedogenic (i.e. in situ, soil-formed) magnetic properties of well-drained, bu¡ered and unpolluted soils appear to be causally related to climate, and speci¢cally, rainfall (Maher et al, 1994;Han et al, 1996). Evaluation of the robust-ness of this climate/magnetism couple is important, as it may provide a quantitative transfer function, enabling calculation of palaeoprecipitation through the Quaternary period, via analysis of the magnetic properties of palaeosols interbedded within the loess sequences of central Asia (Heller et al, 1993;Maher et al, 1994).…”

“…The extent of westward penetration of the monsoonal rainbelt varies with the intensity of the summer monsoon system. Maher et al (1994) examined the relationships between pedogenic magnetic susceptibility and modern climate variables. The magnetic susceptibility (the 'magnetisability') of the Chinese soils is dominantly contributed by trace amounts (V0.3%) of magnetite of ultra¢ne grain size ( 6 V30 nm).…”

Quantifying paleoprecipitation of the Luochuan and Sanmenxia Loess on the Chinese Loess Plateau

“…are closely related with soil forming factors during pedogenesis, especially precipitation. Magnetic parameters, which are fast, inexpensive, non-destructive, and sensitive, have been commonly used as indicators of paleoprecipitation for decades, especially the mass-specific susceptibility (χ) (Balsam et al, 2004;Balsam et al, 2011;Liu et al, 2007;Liu et al, 2012;Maher, 1998;Maher et al, 2002;Maher and Possolo, 2013;Maher et al, 1994;Orgeira and Compagnucci, 2006). Maher and Thompson (1995) reported that pedogenic χ (defined as χ-χ C , where χ C represents the χ of the parent material) rises to a peak until MAP reaches about to reductive dissolution or alteration of the iron oxides.…”