The Effect of Measuring Magnetic Susceptibility of Water Samples by Starting with Isothermal Remanent Magnetization (IRM) before Anhysteretic Remanent Magnetization (ARM)

Abstract

Estimating magnetic properties of water samples by first measuring the Anhysteretic Remanent Magnetization (ARM) before Isothermal Remanent Magnetization (IRM) is induced has been costly due to the discard of samples measured by staring with the latter before the former. However, no clear understanding exists on the effect of measuring magnetic properties values by first inducing IRM before ARM. This study explored the effect of measuring concentration related parameters (χlf, χfd and χARM), a mineral related parameter (S−300) and grain size parameters (χfd% and χARM/SIRM ratio) from water samples by starting with IRM before ARM. Forty three surface water samples were collected from the estuarine of Yangtze River (China) with the aim of measuring magnetic characteristics by starting with IRM before ARM. The results indicated that, measuring magnetic properties by either starting with ARM or IRM led to similar values for χlf, χfd, χfd%, χARM, S−300 and χARM/SIRM ratio (p > 0.05). These results imply that, measuring concentration related parameters does not necessarily require measuring ARM first and then IRM. Researchers can start by measuring any parameter between ARM and IRM without affecting the final results of the water samples, but with proper demagnetization when started with IRM.