Evidence from Mossbauer spectroscopy of neo-formation of magnetite/maghemite in the soils of loess/paleosol sequences in China

Samples of four different loess/paleosol couplets of a loess sequence in Hu angling (China) have been studied with Fe-57 Mossbauer spectroscopy. Each s ample was separated into strongly, weakly and very weakly magnetic fraction s. The iron mineralogy of the strongly magnetic fractions of both loess and soils consists of magnetite/maghemite and hematite together with some sili cates. The soils contain some additional small-particle maghemite. From the spectral behaviour a similarity in terms of morphology and crystal chemist ry for hematite throughout the whole section could be inferred. The ratio o f iron in magnetite and maghemite to that in hematite differentiates well b etween the loess and soil samples. These results strongly suggest the neo-f ormation of magnetite/maghemite in the soils.