Open AccessMagnetic susceptibility of soil: an evaluation of conflicting theories using a national data set
Author(s) -
Dearing J. A.,
Hay K. L.,
Baban S. M. J.,
Huddleston A. S.,
Wellington E. M. H.,
Loveland P. J.
Publication year - 1996
Publication title -
geophysical journal international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0956-540X
DOI - 10.1111/j.1365-246x.1996.tb04051.x
Subject(s) - magnetotactic bacteria , environmental magnetism , ferrimagnetism , magnetic susceptibility , weathering , soil water , magnetosome , earth science , environmental chemistry , paleosol , rock magnetism , geology , geochemistry , soil science , magnetism , superparamagnetism , remanence , magnetite , loess , chemistry , magnetic field , geomorphology , magnetization , paleontology , condensed matter physics , physics , crystallography , quantum mechanics
Magnetic susceptibility values for topsoils across England arc combined with data for soil type, geochemistry and concentrations of magnetotactic bacteria in order to evaluate different theories for explaining soil magnetism. Strongly magnetic soils in unpolluted areas are found over weakly magnetic substrates and are dominated by ultrafine superparamagnetic grains. Magnetotactic bacteria are present in insufficient concentrations to account for strongly magnetic soils, and crop burning is discounted as a major factor. A small number of samples show high values associated with either airborne magnetic particulates from pollution or residual primary ferrimagnetic minerals from igneous substrates. The results are used to construct a new mechanism for the formation of secondary ferrimagnetic minerals that links abiological weathering and biological fermentation processes. The fundamental driving force in the mechanism is Fe supply, which may be linked to climate. Observed causative associations between climate and the magnetic susceptibility of loess‐palaeosol sequences are supported by the findings.