The Ashes of 2017 from the Klyuchevskoy and Kambalnyy Volcanoes: A Comparative Mineralogical-Geochemical Analysis

• Published in: Вестник Пермского университета. Геология
• Main Authors: Silaev, V. I., Karpov, G. A., Kiseleva, D. V., Vergasova, L. P., Makeev, B. A., Tarasov, K. V., Khazov, A. F.
• Format: Article in Journal/Newspaper
• Language: Russian
• Published: Perm State University 2018
• Subjects: Earth Science; volcanoes; Klyuchevskoy; Kambalnyy; ash; chemical and mineral composition; impurity elements; abiogenic organopolymers; Науки о Земле; вулканы; Ключевской; Камбальный; пеплы; химический и минеральный состав; микроэлементы; абиогенные органополимеры; Kamchatka
• Online Access: http://geology-vestnik.psu.ru/index.php/geology/article/view/269; https://doi.org/10.17072/psu.geol.17.4.326

The results of the mineralogical and geochemical study of the ash of the Klyuchevskoy and Kambalnyy volcanoes located in different geological conditions (Klyuchevskoy – Central Kamchatskaya Depression, Kambalnyy - Southeast end Eastern Kamchatka Volcanic Ridge) were obtained in 2017, and allowed making following conclusions. The investigated ashes differ somewhat in chemical composition: the Klyuchevskoy volcano ash is close to andesibasalts, but that from Kambalnyy is close to andesites. According to the normative-mineral composition, they are composed of 65–87% basic plagioclases, 3–22% quartz, 6.5–14% Mg-Fe-Ca silicates (olivine, pyroxene, probably hornblende). In this case, the ashes from the volcano Kambalnyy are characterized by more acidic composition of plagioclase and higher content of quartz. The accessory minerals found in the ashes are presented by spinels (Ulviya magnetite, magnetite, and chromite), ilmenite, rutile, apatite, zircon, pyrite and native metallic-phase (Al, Cu, Fe). Pelitic (silty) fractions are enriched in quartz, but impoverished in Mg-Fe-Ca silicates. As a small admixture in the ash of the Cumulus volcano, titanite, andradite, kaolinite and gypsum are inherently resurgent. The fact of detecting the filamentous forms of abiogenic condensed organopolymer substance of CNO composition in the investigated ashes is of particular importance. It should be noted that, according to the isotope composition of carbon, these formations are identical to similar threads and particles identified in products of modern volcanism in the Kamchatka-Philippine island arc megabelt. Moreover, the analysis showed the presence in the ashes of the Kliuchevskoy and Kambalnyy volcanoes of the carbon substance, which carbon isotopic composition practically coincides with that in the organic filaments. Ashes contain 50 microelements divided into five groups: alkaline and alkaline earth, hydrolyzed, lanthanides, chalcoceridophiles, semi- and non-metals. The analysis leads to the conclusion that the predominantly ...