Confirmation of cost-effective and reliable tracers for aeolian sediment (sand dune) source fingerprinting warrants
further research. Accordingly, the main objective of the work reported in this paper was to investigate the
efficiency of weathering indices in aeolian sediment fingerprinting using a case study of a fragile arid region in
Qom Province, Iran. Eight geochemical elements (Al, Ca, Fe, K, Na, Mg, Si, Ti) and 17 associated weathering
indices were measured in 34 aeolian source samples and 10 sand dune target sediment samples in three absolute
particulate size fractions. For each fraction, three final composite fingerprints (i.e., geochemical elements only,
weathering indices only and a combination of the two) for discerning and ascribing the aeolian sediment sources
were selected. The Modified MixSIR Bayesian un-mixing model was used to apportion aeolian source contributions
using the final composite fingerprints. Regardless of the composite fingerprint used, all results across the
different size fractions suggested that the south-eastern alluvial fan is the dominant (average contribution 50.6%,
SD 19.0%) source of the sand dune samples, with the western alluvial fan being the second most important
(average contribution 38.4%, SD 20.4%) source. Comparisons of the posterior distributions for the predicted
source proportions generated using the nine composite fingerprints (three kinds of composite fingerprints*three
particle size fractions) showed that the composite fingerprints combining the geochemical elements and
weathering indices generated the most powerful source material discrimination. Our results demonstrate the use
of weathering indices alongside more conventional elemental geochemistry tracers for investigations into sand
dune sediment provenance.
