THE EFFECTS OF PARTICLE BREAKAGE AND ABRASION ON THE MAGNETIC-PROPERTIES OF 2 SOILS

As mineral magnetism is used as a tracer for sourcing river and dam se diments, changes in the magnetic properties that may occur during tran sport between the source and sink must be considered. Abrasion and bre akage of particles will occur during transport. These processes were e xamined in simulation experiments with a granitic and a sedimentary so il. The effects of these processes on the magnetic properties of a gra nitic and a sedimentary soil were examined using a simulated breakage/ abrasion experiment. Breakage and/or abrasion had substantial effects on the magnetic properties of both soils. All particle sizes were affe cted, but the magnitude varied through the size range of derived parti cles. The major effect was on the concentration of magnetic minerals, with differences between the concentrations in particle sizes of the o riginal material and those generated by the experiments being as much as 20 times. The effect on the granite soil was to reduce the concentr ations, i.e. derived material was less than original material; whereas for the sedimentary soil the derived particles had higher concentrati ons. The effect on magnetic grain size, as indicated by the magnetic r atios, was less than the effect on the mass magnetic properties, but s till substantial for some ratios for some sizes. (C) 1998 John Wiley & Sons, Ltd.