Determination of anomalies associated with Sb mineralization in soil geochemistry: A case study in Turhal (northern Turkey)

• Soil geochemistry is widely used for the explorations of buried mineral deposits.
• In order to determine the threshold values MAD method was used.
• Anomaly maps of Sb and related elements were drawn with different mapping techniques.
• As + Au and Ag + As + Au multielements clearly define the anomalies of Sb deposits.

In this study, a soil geochemistry survey was conducted and most suitable pathfinder elements for the exploration of Sb deposits and anomaly distribution models of these elements were studied. In this regard, 138 samples taken from the A (top soil) and B horizons of the soil were analyzed for concentrations of Ag, Al, As, Au, Co, Cu, Fe, Hg, Mn, Ni, Pb, Sb, and Zn. All elements had asymmetrical rather than normal distributions. In soil samples from the A horizon, concentrations of Sb, As, Ag, Au and Hg are 0.42–2000 mg/kg, 2.10–5470.40 mg/kg, 10–348 μg/kg, 0.80–66.40 μg/kg and 22–1714 μg/kg, respectively. Concentrations of the same elements in the B horizon were 0.36–2000 mg/kg, 4.10–4019 mg/kg, 2–217 μg/kg, 0.20–53.70 μg/kg and 20–1853 μg/kg, respectively. Cluster analysis indicated that Ag, As, Au, and Hg are strongly correlated with Sb, and therefore, they are the most suitable pathfinder elements for the exploration of Sb deposits. Threshold values of these elements were determined with the use of median absolute deviation (MAD) method. In addition, an anomaly map of each element and the element groups yielding the most ideal results for the exploration of Sb deposits were also ascertained using multi-element mapping. Results indicate that As + Au and Ag + As + Au are the most ideal multi-elements in the exploration of Sb deposits. In this method, some elements that yield weak anomalies when solely used were found to be effective when combined with other elements. These element associations can be successfully used in future Sb geochemical exploration works.According to enrichment factor (EF) and integrated pollution index (IPI) calculations, both A and B horizons of the soil are enriched in all examined elements. Element enrichment in A horizon is in the rank of Sb > As > Au > Ni > Hg > Co > Mn > Cu > Fe > Zn > Pb > Ag, while the rank of elements in B horizon is Sb > As > Ni > Hg > Au > Co > Cu > Fe > Mn > Zn > Pb and Ag. The A horizon hosts extremely high Sb and As enrichment; very high Au and Ni enrichment; and significant Co, Cu, Fe, Hg, Mn, Pb and Zn enrichment. B horizon is characterized by extremely high Sb and As enrichment; very high Ni enrichment; and significant Au, Co, Cu, Fe, Hg, Mn, Pb and Zn enrichment. According to integrated pollution index calculations, 44.9% of samples from the A horizon and 44.11% from the B horizon exhibit an extremely high level of pollution.