Marcial waters are the most famous deposit of ferruginous waters in north-western Russia. It is where Russia’s oldest resort, which opened in 1719, is situated. Four water boreholes (Bh) with different water mineralization and iron content are in use today. Marcial waters have been studied for 300 years in terms of their chemical composition, mainly the content of major elements. However, precise investigations of trace elements have not been performed previously. Recently, five-year monitoring (2015–2019) of the distribution of trace elements in water boreholes and other water bodies located in the resort’s area was accomplished. Also, the chemical composition (trace elements) of host rocks and the mineral phases forming them were analyzed to assess their possible contribution to the mineralization of the studied water. It has been shown that Marcial waters contain a wide range of trace elements with concentrations from 0.001 to 260 µg∙kg-1, and displayed chemical stability for most elements during the 5 years. High concentrations of some trace elements in Marcial waters can be explained by their transfer from silicate, accessory minerals and sulfides of the host rocks. The investigations showed that waters are formed as a result of infiltration waters interacting with ore and silicate minerals, which controls the specific chemical composition. REE distribution indicates different mechanisms of their accumulation, which justifies the distinction of two contrasting water types formed as a result of mixing high-ferruginous waters of Bh 4 with infiltration water.

26.2.2021