Investigation of the relationship between rare earth elements, trace elements, and major oxides in soil geochemistry

Investigation on the behavior of elements in the soil is important both in exploration and environmental geochemistry studies. Rare earth elements (REEs) are the most useful among all trace elements. REE studies have shown that they have important applications in igneous, sedimentary, and metamorphic petrology. This work aims to investigate the relationship of these elements with one another and the behavior of the major oxides and trace elements with REEs. Soil samples were obtained from the alteration site possibly related to mineralization and were analyzed for major oxides, trace elements, and REEs. The relationships between the major oxide–trace element/heavy metal and REE were investigated by statistical methods, such as descriptive statistics, correlation coefficient, and principle component analysis. According to the correlation coefficient matrix, light REEs (LREEs) showed weak to moderate negative correlation with MgO and MnO and moderately positive correlation with SiO₂ and K₂O. No association was detected between the heavy REEs (HREEs) and the main oxides, but a strong positive correlation with LREEs was observed. For the trace elements, LREE showed a weak positive correlation with Ba and Sn and moderate to strong positive correlation with As, Hf, Nb, Rb, Ta, Th, U, W, and Zr. They also displayed weak to moderate correlation with Sc, Co, Zn, Ni, and V. HREE showed weak to moderate positive correlation with Ni, Cs, Ga, Hf, Th, Zr, As, and LREE. Although REEs exhibited no direct correlation with Au and Ag, they showed a good correlation with some trace elements that are related to hydrothermally altered products. This study showed that REEs can also be used in exploration and environmental geochemistry studies by exploiting the relationship between REEs and other trace/heavy metal elements.