Ore-bearing rocks and natural waters of the Pitkäranta ore district (near the “Arsenic” shaft, the Hopunvaara mine field) were sampled and analyzed. The permanganate value as well as iron and manganese contents in surface water are higher than MPC values, while water samples from the “Arsenic” shaft have the elevated contents of zinc, copper, and arsenic. The Fe, Mn, Cu, Zn, Cr, As, and Ni speciation in waters have been determined by thermodynamic calculations, taking into account the possibility of the formation of metal complexes with humic and fulvic acids. The fulvic acid is almost completely consumed for the formation of the complex Fe(OH)₂Fu^-. Ni, Cd, Co occur mainly in the ionic form, and the fraction of Mn and Zn in the ionic form is also significant.

Abandoned mines are sources of potentially toxic chemical elements, although the development of these objects was completed. The Lupikko I mine area (Karelia Republic, Russia) is an excellent example of such technogenic objects. It is one of the largest mines in the Pitkäranta area, which was abandoned more than one hundred years ago. The dump rocks here are characterized by significant mineral diversity. Disseminated ore mineralization of the study area contains heavy metals, which enter the natural waters due to the oxidative dissolution of sulfides. Dump rocks and water from the Lupikko I mine area were collected to research the behavior of toxic elements. The samples were analyzed using ICP-MS, ICP-AES, potentiometric titration, ionic chromatography, X-ray microanalysis, X-ray fluorescence, and SEM to obtain information about the geochemical environment. According to new data, the content of Fe, Zn, Cu, Pb, Cd, and Ni in the natural waters of the mine significantly exceeds the geochemical background. For a more detailed study of the behavior of heavy metals, equilibrium-kinetic modeling, which considers the dissolution rate of ore minerals and the accumulation of toxic elements over time, was applied. A comparison of modeling data and field observations agreed. It was also found that for accurate modeling of Fe behavior, it is necessary to consider the organic matter content. Despite some model limitations, such retrospective assessments allow us to approve the applicability of this method for forecasting estimates.

Differences between two types of highly differentiated granites of the Salmi batholith: namely Li-siderophyllite topaz-bearing and Li–F topaz-zinnwaldite granites, were determined based on the study of their structural-morphological, mineralogical and geochemical features are determined. The high degree of the differentiation of these granites is confirmed by the presence of primary topaz, Li-micas of magmatic origin and by the presence of significative tetrad effect of M type. These granites are distinguished due to the types of their micas, the content of topaz (up to 1 and 15%, respectively), the morphology of granite intrusions and the geochemistry of rare elements. The Li–F zinnwaldite granites are depleted in REE and enriched in Ta, Hf, Ba, Sr compared to the Li-siderophyllite granites. The Li-siderophyllite granites clearly fit to the general evolution trend of the Salmi batholith granites, while the genesis of Li–F zinnwaldite granites seems to be associated not only with the processes of crystallization differentiation of the melt but also with the active addition of some components, primarily F and Li, probably from a deeper source, including the mantle.

The origin of the anorthosite-rapakivi granite-bearing rock complexes was a topic of research for geologists for more than a century. Magmatic systems that produce these complexes were widely developed in the Precambrian and have no direct analogues in modern times. The main goal of this study was to characterize the conditions under which primitive granitoids formed and to shed light on the history of ore matter transport during these stages. The object of the research was granite porphyry dikes—a subeffusive analogue of rapakivi granite from the Salmi batholith in the Fennoscandian Shield. Characteristic solid-phase inclusions of a mineral paragenesis of mafic rocks, as well as inclusions of sulfide melts, were found in zircon from this type of rock. These sulfide inclusions were homogenized by heating, and subsequently, the trace element composition was determined by the LA-ICP-MS method. The geochemistry of zircons was studied by the SIMS method, and the temperature of their formation was determined using a Ti-geothermometer. The temperature of the studied zircon grain formation varied from 925 to 765 °C. The values of ƒO2 for the early stages of the rock formation were in the region below the boundary of the FMQ buffer. The presence of two sulfide melts at the time at which the sulfide inclusions were captured by the zircon, pyrrhotite-chalcopyrite, and sphalerite-chalcopyrite compositions was established. The capture of sulfide inclusions from the pyrrhotite-chalcopyrite composition occurred above 841 °C, while in sphalerite-chalcopyrite, they occurred at a lower temperature of 765 °C. The connection between the formation of granite porphyry with mafic melts that form rocks of the gabbro and anorthosite types was established.

The problem of the world-class PGE-Cu-Ni Norilsk deposits’ origin has attracted geologists for several decades. The main goal of this study is to determine the specific features of ore-bearing intrusions in comparison with thousands of similar barren intrusions widespread within the Siberian igneous province, and to establish their genesis. As a result of statistical processing of previously published isotope-geochemical data and obtained by the authors, systematic differences were found in the distribution of the isotopic ratio of Nd in ore-bearing and barren intrusions, as well as in volcanic rocks at the Norilsk region. Thus, ore-bearing rocks in ten deposits (Talnakh, Kharayelakh, Norilsk 1, South-Maslovsky, North-Maslovsky, Norilsk 2, Chernogorsky, Zub-Mrksheydersky, Pyasino-Vologochansky, Imangdinsky), different in Ni and PGE reserves, show a very narrow range of Nd isotopic ratio, Ԑ_Nd(T) = 1.0 ± 1.0 (2σ, N = 139), whereas barren and volcanic rocks are characterized by a rather wide Ԑ_Nd(T) range, from −10 to +7 units (N = 256). Furthermore, ore-bearing intrusions are characterized by reduced and compact variations of the La/Lu ratio due to lower concentrations of light lanthanides. For the first time the authors studied two new intrusions penetrated by MD-48 and MD-60 boreholes drilled by Norislkgeologia LLT at the eastern part of the Mikchangda area. Their economic values are still unclear and should be estimated using geochemical methods. Both intrusions lie in the Devonian rocks, have similar thickness and mineral composition, but differ in textural and structural features, which indicate a rapid crystallization of the MD-48 intrusion. According to the contents of the major oxides, the rocks in MD-48 and MD-60 are identical, but they differ in U/Nb, La/Sm, and Gd/Yb ratios. It is important that the rocks in the MD-60 borehole are characterized by Ԑ_Nd(T) = 1.0 ± 0.6 (2σ) and fall into the range of ore-bearing intrusions, whereas the rocks in MD-48 have Ԑ_Nd(T) 2.4 ± 0.9, and, thus, are outside of ore-bearing intrusions. Therefore, Ԑ_Nd(T) values can be used as a local criterion for the estimation of economic potential of mafic intrusions, which is demonstrated for the Mikachangda area.

New data are presented on the quartz porphyry dikes of the Salmi batholith belonging to anorthosite–rapakivi granite rock complexes. The relationships of various igneous rocks of the Salmi batholith and metasomatites were determined along with the isotopic U–Pb age by the LA–ICP–MS technique and the temperature of zircon formation by the Ti content.