The boiling spring Bastion is located downstream from the thermal slope Vitrazh, in the middle of a steep, grassy slope. Its geyserite edifice is a protrusion of bedrock in the form of a wall 3 m high and resembles a fortress wall with a jagged upper edge. It was first described and named "Zastenok" by members of the GOSA (Geyser Observation and Study Association) expedition, who worked in the Valley of Geysers in July 1991 (Bryan et al., 1991): "There are 3 boiling springs inside one structure. Only during the eruptions of the Grot and immediately after them it can work as a geyser." The name Bastion was first used in the book of Sugrobov et al. (2009), and become accepted. Eruptions of Bastion were observed in the upper and lower parts of its edifice. Recently, they come from two gryphons in the upper part: "above the right edge of the edifice there is a narrow fountain 0.5–1 m high, above the left edge there are wide splashes up to 0.5 m high" (Leonov, 2017). In 2024, the gryphons in the upper crater worked almost continuously. It was not damaged by the 2007 and 2014 landslides.
References
Bryan S.T., Hobart J., Warnock B., Rinehart J.S., Fenimore M., Colvin B. The Geysers of 'The Valley of Geysers'. A special report of GOSA Transactions. USA, California: B&J Printing. 1991. 60 p.  Леонов А.В. Каталог гейзеров Кроноцкого заповедника. Долина гейзеров и кальдера вулкана Узон: история и современность. М.: Изд-во ООО «Реарт». 2017. 384 с. Сугробов В.М., Сугробова Н.Г., Дрознин В.А., Карпов Г.А., Леонов В.Л. Жемчужина Камчатки – Долина Гейзеров, научно-популярный очерк, путеводитель / Отв. ред. Поляк Б.Г. Петропавловск-Камчатский: Изд-во «Камчатпресс». 2009. 108 с. |
