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Recognition and detailed characterization of solid particles emitted from thermal power plants into the environment is highly important due to their potential detrimental effects on human health. Snow cover is used for the identification of anthropogenic emissions in the environment. However, little is known about types, physical and chemical properties of solid airborne particles (SAP) deposited in snow around thermal power plants. The purpose of this study is to quantify and characterize in detail the traceable SAP deposited in snow near fossil fuel thermal power plant in order to identify its emissions into the environment. Applying the scanning electron microscopy-energy dispersive spectroscopy, and X-ray diffraction, mineral and anthropogenic phase groups in SAP deposited in snow near the plant and in fly ash were observed. We identified quartz, albite and mullite as most abundant mineral phases and carbonaceous matter, slag and spherical particles as dominate anthropogenic phases. This is the first study reporting that zircon and anthropogenic sulphide-bearing, metal oxide-bearing, intermetallic compound-bearing and rare-earth element-bearing particles were detected in snow deposits near thermal power plant. The identified mineral and anthropogenic phases can be used as tracers for fossil fuel combustion emissions, especially with regard to their possible effect on human health.

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This study investigates the process of formation of ooidal ironstones in the Upper Cretaceous-Paleogene succession in western Siberia. The formation of such carbonate-based ironstones is a continuing problem in sedimentary geology, and in this study, we use a variety of data and proxies assembled from core samples to develop a model to explain how the ooidal ironstones formed. Research on pyrite framboids and geochemical redox proxies reveals three intervals of oceanic hypoxia during the deposition of marine ooidal ironstones in the Late Cretaceous to the Early Paleogene Bakchar ironstone deposit in western Siberia; the absence of pyrite indicates oxic conditions for the remaining sequence. While goethite formed in oxic depositional condition, chamosite, pyrite and siderite represented hypoxic seawater. Euhedral pyrite crystals form through a series of transition originating from massive aggregate followed by normal and polygonal framboid. Sediments associated with goethite-chamosite ironstones, encompassing hypoxic intervals exhibit positive cerium, negative europium, and negative yttrium anomalies. Mercury anomalies, associated with the initial stages of hypoxia, correlate with global volcanic events. Redox sensitive proxies and ore mineral assemblages of deposits reflect hydrothermal activation. Rifting and global volcanism possibly induced hydrothermal convection in the sedimentary cover of western Siberia, and released iron-rich fluid and methane in coastal and shallow marine environments. This investigation, therefore, reveals a potential geological connection between Large Igneous Provinces (LIPs), marine hypoxia, rifting and the formation of ooidal ironstones in ancient West Siberian Sea.

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