Abstract:
A regional soil geochemical survey was carried out on the island of Lesvos, NE Aegean Sea, Greece, using an average density of 1 sample/25 km2 with the aim to investigate the geochemical variability of major and trace elements. The island encompasses a variety of rock and mineralisation types, including the Lesvos petrified forest, a well-documented geosite of international scientific importance, providing an opportunity to study how variations in lithology and hydrothermal mineralisation impact on elemental soil geochemistry. In total, 66 soil samples (0-20 cm depth) were collected across the entire island and the <2 mm fraction analysed for a variety of elements following a hot aqua regia digestion. In addition, 28 rock samples were also collected and analysed to assist in the interpretation of the soil geochemical patterns. The soil geochemical data were processed by multivariate statistical methods (factor and hierarchical cluster analysis) and Geographic Information System methods. The procedures used enabled the identification of several soil geochemical patterns that correlate with known rock types and mineralisation occurring on the island. Specific major and trace elements (Ba, Ca, Cd, Co, Cr, Fe, K, Na, Mg, Mn, Ni, Sr, Zn) exhibit pronounced concentration changes across the major lithological units, with median concentrations displaying orders of magnitude differences between the soil developed over different lithologies. A suite of trace elements (As, Cu, Mo, Pb, Sb) in soil fingerprint the hydrothermal mineralisation, exhibiting geochemical anomalies around known epithermal and porphyry-style deposits. No major diffuse anthropogenic contamination by potentially toxic elements appears to have affected the soil at the sampling density of 1 sample/25 km2. It is concluded that the applied soil sampling density has effectively mapped the regional patterns of the geochemical landscape of Lesvos island, with broader implications for geochemical mapping in similar regions characterized by lithological diversity.
https://doi.org/10.1016/j.apgeochem.2026.106893
