The Geological Structure Features of Hydrothermal Discharge Zones at Pauzhetsky Geothermal Deposit According to Geophysical Data (South Kamchatka, Russia)
Sergey FEOFILAKTOV, Sergey RYCHAGOV, Ivan NUZHDAYEV, Yury BUKATOV, Denis DENISOV
[Institute of Volcanology and Seismology, Russia]
The work is devoted to solution of a fundamental scientific problem - understanding the structure and physical nature of hydrothermal discharge zones using the example of the Pauzhetskaya hydrothermal system and the geothermal field of the same name. Studies were conducted in the area of two large thermal fields – Verhne (Upper) -Pauzhetsky and Vostochno (East)-Pauzhetsky. It was previously established that these thermal fields were confined to elevated tectonic or tectonic-magmatic blocks, within which there was an active circulation of hydrotherms and the mixing of waters of the lower and upper aquifers (Structure ..., 1993). Many fundamental issues remained unresolved despite the large range of work carried out and the long-term field exploration. The fundamental issues include: the structure of the geothermal coolant circulation zones, the physical nature of the sources of tectonic deformations, the position and type of heat source. In order to solve these problems, the staff from Institute of Volcanology and Seismology of Far Eastern Branch of Russian Academy of Sciences together with colleagues from Moscow, Irkutsk and other scientific centers of Russia conduct a joint geological, geophysical, hydrogeochemical, mineralogical, etc. study of the steam hydrothermal discharge zones at the Pauzhetsky geothermal field. The complex of geophysical methods includes: high-precision gravimetry, magnetometry, electrical exploration (VES and SP), soil thermometry. The presence of a subintrusive body of medium or basic composition was established at a small depth (first tens of meters) according to the results of geological and geophysical data interpretation for the Vostochno (East)-Pauzhetsky thermal field (Feofilaktov et al., 2017). Unload of deep alkaline hydrotherms was timed to the apical parts of this body. The block of tightened rocks was also distinguished in the center of the geological structure under the Verhne (Upper) -Pauzhetsky thermal field. A zone of elevated fracture-pore permeability was revealed along the periphery of the block. In general, new data on the structure of the upper aquifer and the upper aquifer of the Pauzhetsky hydrothermal system were obtained; steam and water saturated areas and portions of fractured pore circulation of ascending hydrothermal solutions were identified. This work was supported by the Russian Foundation for Basic Research (Projects No. 18-35-00138 and No. 19-05-00102) and Far-Eastern Division of the Russian Academy of Sciences (Project No. 18-2-003).
|        Topic: Geophysics||Paper Number: 13029|