ORGANIC MATTER IN THE PARATUNKA GEOTHERMAL FIELD (KAMCHATKA) THERMAL WATERS

Abstract

Link for citation: Poturay V.A. Organic matter in the Paratunka geothermal field (Kamchatka) thermal waters. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 8, рр. 98-109. In Rus. The relevance of the research is determined by the need to obtain actual data on the composition of organic compounds in thermal mineral waters. Hydrothermal systems contain different classes of organic matter, its composition in the Far East thermal waters being poorly investigated. The organic matter study is primarily aimed at elucidating the mechanisms of organic components transformation under high temperatures and pressure. This study contributes to deeper understanding of the processes occurring in the system «water–rock–organic matter». The main aim of the research is to determine the organic compounds composition and genesis in the Paratunka geothermal area (Northern and Karymshin sites) thermal waters; estimation of the hydrocarbons molecular weight distribution; compare the obtained data with that for other hydrothermal systems of Kamchatka. Objects: the Paratunka hydrothermal system (thermal water from deep wells in the Northern and Karymshin areas), the Mutnovka and Uzon hydrothermal systems (steam-water mixture from deep wells in the Dachnoe and North Mutnovskaya thermal fields, and thermal water from shallow wells in the Eastern thermal field). Methods: field routes, solid-phase extraction, capillary gas chromatography-mass spectrometry, calculation of geochemical hydrocarbon distribution indices. Results. In the Paratunka geothermal area thermal waters 40 organic compounds are found, which belong to 11 homological series. Aromatic and aliphatic hydrocarbons of thermogenic (formed as a result of thermocatalytic transformation of organic residues) and bacterial origin reach their maximum distribution. The specific molecular-weight distribution of normal alkanes showing only even low-molecular-weight homologues is characteristic of the Karymshin thermal waters. Comparison of the data with the results of the study of organic matter in Kamchatka (the Paratunka, Mutnovka, and Uzon geothermal areas) demonstrates a great similarity of main organic components composition, all of them showing a sharp predominance of aliphatic and aromatic hydrocarbons.