Results of geological and geochemical investigations of Kaplanov kudurs in Sikhote-Alin, Russian Far East

A series of studies was carried out at the Kaplanov kudurs in the upper reaches of the Kolumbe river (the territory of Sikhote-Alin biosphere reserve, Russia) in order to confirm the “rare earth” hypothesis as one of the possible causes of geophagy and consumption of mineralized spring water on kudurs. The mineral and chemical content of spring water and mineral soils of lithogenic substances, consumed by animals at the Kaplanov kudurs in the upper reaches of the Kolumbe river (the territory of Sikhote-Alin biosphere reserve, Russia). Previously unknown data on microelement composition of the minerals consumed by animals was received. It was found that the composition of water of various kudurs differs immensely and forms mainly in restored gley environments (sometimes in restored environments with high concentrations of sulfates). It was also found out that the microelement composition in spring waters can significantly vary over time. When this happens, the most variable are Al, Fe, Co, Ni, Cu, Zn, Ba, Sr, and some rare metals from the rare earth elements (REE) group and lanthanides. It was confirmed that one of the elements which attracts the animals in spring water and in “edible” subsoils is Na. However, Na is not the only element, which is searched by the animals at the kudurs, as consumed water and soil on some kudur contain an insignificant amount of it with simultaneously increased concentrations of a number of trace elements, including from the group REE.