Magnetite weathering in a Vertisol with seasonal redox-dynamics

作者：Fischer H^*; Luster J; Gehring A U

来源：Geoderma, 2008, 143(1-2): 41-48.

DOI：10.1016/j.geoderma.2007.10.004

• magnetite
• grain size
• dissolution
• redox-dynamics

We investigated soil samples from a Vertisol in a flat lying flood plain in the savannah woodland of southern Mali, which is characterized by a water regime governed by regularly occurring wet and dry seasons. The soil was subdivided into four horizons which differed in the content and speciation of the redox-sensitive elements and in the length of waterlogging. Magnetically, the profile could be subdivided into two parts. The magnetic susceptibility, the hysteresis parameters M-r, M-s, and B-c, as well as the coercivity of remanence B-cr, indicate that the upper two horizons differed from the lower two horizons by a higher content of magnetite and a larger contribution of multi-domain size magnetite grains as compared to single-domain size grains. A comparison of the chemical and magnetic data suggests that dissolution of magnetite in our soil is driven by a seasonal change between anoxic and oxic conditions.

• 出版日期2008-1-15