Detection of seasonal-specific potential source areas of mineral dust on Crete (Greece) based on isotope measurements and mineralogical investigations

The Sahara is the Earth’s largest dust source, producing dust plumes that impact the whole planet. The eastern Mediterranean is one of the areas significantly affected by Saharan dust and its deposition.
The geochemical and mineralogical composition of the deposited mineral dust particles depend on their source area and on spatiotemporal variability of the source areas.
Although being of great importance for local soil formation and soil distribution, the impact of changes in dust provenance has not been extensively studied in the eastern Mediterranean. Thus, further research is required to characterize dust deposition fluxes, transport trajectories and the geochemical and mineralogical composition of deposited mineral dust.
Modelled trajectories of dust events provide good insights on aeolian transport routes, but if larger distances are covered over land, the exact source area of the deposited material cannot be traced with certainty. The question also arises as to whether the composition of the mineral dust deposited differs due to spatial sorting and thus its influence on the deposition area.
In order to gain insight into the dynamics of dust deposited on Crete, we present results from eight passive deposition traps (marble samplers) that were installed in western Crete at various sites around the Lefka Ori mountains. Monthly sampling was performed between March 2023 and June 2024, which provides us a unique temporal and spatial coverage.
Here we used a multi-proxy fingerprinting approach including Nd-Sr isotopic composition, mineralogy and grain-size distribution. The isotope analyses show a temporal shift in the potential source areas over the year, but no significant spatial differences. This spatial homogeneity in the isotopic signature of deposited dust suggests a minor influence of local inputs, which are characterized by distinct geological contexts, which is confirmed by the mineralogy. Samples with a coarser and well-sorted grain-size distribution likely track larger dust events, as a relatively larger proportion originates from the same source. The aim is to combine the results and thus to highlight and classify the intensity of influence of different source areas on the soil development of western Crete. In the long term, an analysis of back-tracking trajectories is to be carried out and combined with the results of the isotope analyses, which we expect to improve the informative value of the potential source areas.