The Vuoriyarvi Devonian carbonatite–ijolite–pyroxenite–olivinite complex comprises several carbonatite fields: Neske Vara, Tukhta-Vara, and Petyayan-Vara. The most common carbonatites in the Tukhta-Vara and Neske-Vara fields are calciocarbonatites, which host several P, Fe, Nb, and Ta deposits. This paper focuses on the Petyayan-Vara field, in which the primary magmatic carbonatites are magnesian. The least altered magnesiocarbonatites are composed of dolomite with burbankite and are rich in REE (up to 2.0 wt. %), Sr (up to 1.2 wt. %), and Ba (up to 0.8 wt. %). These carbonatites underwent several stages of metasomatism. Each metasomatic event produced a new rock type with specific mineralization. The introduction of K, Si, Al, Fe, Ti, and Nb by a F-rich fluid (or fluid-saturated melt) resulted in the formation of high-Ti magnesiocarbonatites and silicocarbonatites, composed of dolomite, microcline, Ti-rich phlogopite, and Fe–Ti oxides. Alteration by a phosphate–fluoride fluid caused the crystallization of apatite in the carbonatites. A sulfate-rich Ba–Sr–rare-earth elements (REE) fluid (probably brine-melt) promoted the massive precipitation of ancylite and baryte and, to a lesser extent, strontianite, bastnäsite, and synchysite. Varieties of carbonatite that contain the highest concentrations of REE are ancylite-dominant. The influence of sulfate-rich Ba-Sr-REE fluid on the apatite-bearing rocks resulted in the dissolution and reprecipitation of apatite in situ. The newly formed apatite generation is rich in HREE, Sr, and S. During late-stage transformations, breccias of magnesiocarbonatites with quartz-bastnäsite matrixes were formed. Simultaneously, strontianite, quartz, calcite, monazite, HREE-rich thorite, and Fe-hydroxides were deposited. Breccias with quartz-bastnäsite matrix are poorer in REE (up to 4.5 wt. % total REE) than the ancylite-dominant rocks (up to 11 wt. % total REE).

The NE Fennoscandian Shield comprises the Northern Belt in Finland and the Southern Belt in Karelia. They host mafic-ultramafic layered Cu-Ni-Cr and Pt-Pd-bearing intrusions. Precise U-Pb and Sm-Nd analyses indicate the 130-Ma evolution of these intrusions, with major events at 2.53, 2.50, 2.45, and 2.40 Ga. Barren phases were dated at 2.53 Ga for orthopyroxenites and olivine gabbro in the Fedorovo-Pansky massif. PGE-bearing phases of gabbronorites (Pechenga, Fedorovo-Pansky, Monchetundra massifs) and norites (Monchepluton) are 2.50 Ga old. Anorthosites of Mt. Generalskaya (Pechenga), the Fedorovo-Pansky, and Monchetundra massifs occurred at 2.45 Ga. This event produced layered PGE-bearing intrusions in Finland (Penikat, Kemi, Koitelainen) and mafic intrusions in Karelia. The Imandra lopolith dikes occurred at the final phase (2.40 Ga). Slightly negative εNd and I_Sr values (0.703–0.704) suggest that intrusions originated from an enriched mantle reservoir. Low ³He/⁴He ratios in accessory minerals (ilmenite and magnetite) indicate an upper mantle source. Large-scale correlations link the Fennoscandian Shield with the Superior and Wyoming cratons.

Natural contamination of arsenic (As) and heavy metals (HMs) poses a health threat in many regions. Ambagarh Tehsil, Rajnandgaon, Central India, is a heavily polluted area due to mineralization of geogenic As and HMs in the environment, i.e., water, plants, and soil. In this work, contamination extents and sources of As and HMs (Cr, Mn, Cu, Zn, and Pb) in water, soil, and common plants were investigated to understand the main entry route of these toxic elements in human and domestic animals. The mean concentrations of total As in surface water, groundwater, surface soil, plant leaves, and animal stool samples of $0.031\pm 0.009{\mathrm{mg}\mathrm{mL}}^{-1}$ , $0.360\pm 0.114{\mathrm{mg}\mathrm{mL}}^{-1}$ , $192\pm 65\mathrm{mg}{\mathrm{kg}}^{-1}$ , $5.61\pm 4.78\mathrm{mg}{\mathrm{kg}}^{-1}$ , and $51.0\pm 7.6\mathrm{mg}{\mathrm{kg}}^{-1}$ , respectively, were found. The speciation, sources, enrichment, and toxicities of the As and other HMs are discussed, together with some associated health hazards, exemplified in domestic animals exposed to the contaminated water and food.

Monchegorsk is an intrusion complex of basic and ultrabasic rocks of the Paleoproterozoic age. This complex formed during active magmatic mobility that took place in NE Scandinavia 2.5 Ga years ago. These were the subject of intensive exploration and exploitation at the beginning of the 20th century, the latter carrying on through to the beginning of the 21st century. This contributed to the creation of some different forms of post-industrail mining infrastructure in the area. Many mining settlements, including Monchegorsk, mining plants, adits and quarries were established during this time, the relics of which are still present today. The Monchegorsk intrusions complex is formed by several fragmented massifs: Traviannaya, Kumuzhia, Nittis, Sopcha, Nyud, Poaz, and Monchetundra, the highest elevations of which reach up to 1000 m above sea level. These massifs form a landscape of “islands” and mountain ranges that have influence upon the regional landscape over several tens of kilometers. Their geography is characterized by numerous reliefs, glacial cirques, rocky thresholds with waterfalls and trough lakes. The potential of this region lies in the heritage of historical exploitation, numerous monuments of which have been preserved to this day. An important value is a landscape resulting from the relief of these mountains, highlighted by glacial activity in the Pleistocene. There are also interesting examples of Arctic fauna and flora, and of the rocks that form the bedrock in this intrusion. Some of the mineralization of these outcroppings can also be admired in the collections of the local museum that serves as a geocenter. The possibility of admiring relatively easily accessible views (the international route St. Petersburg–Murmansk–Kirkenes passes through the middle of the hills) and the interesting geology of the area abounding in rocks of mineralogical significance, their exposures, and history, along with the possibility of observing various post-industrail forms, make this area of great tourist potential. This article describes the most interesting exposures of outstanding tourist value and proposes routes connecting these points. It also discusses the problem of securing these exposures and the necessary tourist infrastructure, which is currently lacking.