Zeolite containing rocks of kudurs and reasons of geophagy within the territory of Sikhote-Alin Nature Zapovednik, Far East of Russia

We studied mineral and chemical composition of the liquid and lithogenous substances consumed by wild ungulates in the Sikhote-Alin Biosphere Nature Zapovednik, Far East of Russia. Based on geological and geochemical information analysis, we found that igneous-sedimentary rocks of rhyolite and rhyodacite composition form most of the kudurs. Kudurs are formed on the zeolitized rocks and laid down within the paleo-volcano caldera and within the volcano-tectonic basin to the northwest from the volcanic edifice. The zeolitization of the rocks is predominantly connected with the hydrothermal reconversion of the contained volcanic glass ash particles. The animals are attracted to the kudurs by the low-mineralized spring waters with the high concentration of Na and a variety of microelements formed in the igneous-sedimentary rock formation and the argillous products of weathering of the zeolitized rocks. The acid (HCl, pH1) extracts from the kudurits extract more actively calcium (30-50% from the gross contents) and Na (about 25%). Be, Co, Sr, Cd, and Pb are the most fluent in the microelement composition. Transition into the dissolved form of rare earth elements (La, Ce, Pr, Nd, Sm, Gd, Tb) and also Y and Sc varies from 1 to 3.5% from the gross contents.