Environmental assessment of lake sediments using magnetic susceptibility and hysteresis parameters: A case study of lake Tondano, Indonesia

Lake Tondano is experiencing increasing environmental pressures from erosion, sedimentation, and land-use changes within its catchment area.However, information on the spatial variability of sediment magnetic properties remains limited.This study aimed to characterize the magnetic properties of Lake Tondano sediments using environmental magnetic parameters and to evaluate their spatial distribution across the lake.Surface sediment samples were collected from 30 locations and analyzed for low-frequency magnetic susceptibility (χ LF ), frequency-dependent susceptibility (χ FD %), and hysteresis parameters (Ms, Mrs, Hc, and Hcr).The magnetic susceptibility data were further processed using spatial interpolation to examine the distribution of magnetic properties.The χ LF values exhibit considerable spatial variability, indicating differences in magnetic mineral concentrations among sampling locations.Relatively high χ LF values were observed in the western and central-western parts of the lake, suggesting enhanced accumulation of magnetic minerals in these areas.The generally low χ FD % values (<5%) suggest a predominance of coarse-grained magnetic particles and a limited contribution from superparamagnetic grains.Hysteresis and Day plot analyses of two representative samples indicate the presence of low-coercivity ferrimagnetic minerals with pseudo-single-domain to multi-domain magnetic behavior, consistent with magnetite-dominated magnetic assemblages.These magnetic characteristics suggest that the sedimentary magnetic fraction is predominantly derived from detrital material associated with the surrounding volcanic catchment.Overall, this study provided the first spatially distributed environmental magnetic dataset for the Lake Tondano sediments and baseline information on the variability of magnetic susceptibility and magnetic mineral characteristics across the lake.The results demonstrate the usefulness of environmental magnetic parameters for characterizing sediment magnetic properties in tropical volcanic lake environments.