Holocene Kamchatka volcanoes
Institute of Volcanology and Seismology
Kamchatka, Russia
 
 
Monogenetic volcanic vents of the Elovka River basin

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A number of fresh-looking isolated volcanic vents are located at the far eastern flanks of the Sredinny Range in the Elovka River basin. Three of them appeared to be as young as the Holocene (Pevzner, 2006): Kinenin maar (5721N, 16058E; wall elev. 583.4 m; GVP number 1000-551); Bliznetsy twin lava flows (5721N, 16122E; elev. of the highest point 265.0 m; GVP number 1000-552) and Shisheika lava dome (57 09 N, 16105E; elev. 378.5 m; GVP number 1000-511).

Kinenin maar (Figs. 1 and 2) was named by Maria Pevzner (2006) by the Kinenin River (a tributary of the Elovka River). The maar is filled with a lake ~1 km across. Based on tephrochronological data and radiocarbon dates, Kinenin maar was formed by a phreato-magmatic eruption ~1.1 ka BP (Pevzner, 2006). The crater wall is composed mostly of desintegrated host rocks with some admixture of fresh mafic bombs at the top of the sequence. The tephra of this eruption was spread to ENE and can be traced as far as the Pacific coast, >100 km from the source (Figs. 3 and 4). The volume of the erupted material is estimated at ~0.5 km3.

Juvenile mafic bombs from Kinenin maar are characterized by high Mg (Mg#0.65-0.67), Cr, Co, Ni, V, and Ba content (Babansky et al., 2006). These features make Kinenin basalts similar to the mafic tephra erupted from Shiveluch volcano ~7600 14С yrs BP (Volynets et al., 1997). Kinenin basalts, however, have higher HFSE concentrations compared to the Shiveluch tephra that may have resulted from the participation of the HFSE-enriched source in Kinenin magma genesis.

Bliznetsy ("twins" in Russian) are two adjacent lava flows erupted from closely spaced vents, which are located 25 km to the east of the Kinenin maar and 80 km north of Shiveluch volcano (Figs. 5 and 6). Area of the two lava flows is 5 km2 (length 2.5 km, width 2 km). Volume of the erupted medium-K andesite is estimated at 0.15 km3. Based on tephrochronological and radiocarbon data, the eruption took place ~3 ka BP (Pevzner, 2006).

Shisheika lava dome (Fig. 7) is located at the right bank of Shishei River, 60 km NNW of Shiveluch volcano. Area of the lava body is 4 km2; average thickness is ~150 m. Volume of erupted medium-K andesite-dacite is estimated at 0.5-0.6 km3. The erupion took place ~4.2 ka BP as suggested by the stratigraphic position of its tephra and a radiocarbon date obtained below the latter. The eruption produced also a minor tephra fall.

The described three volcanic centers erupted basalts, basaltic andesites, andesites and dacites. All the rocks have similar geochemical features: they belong to medium-K calc-alkaline series and have an arc-type trace elements patterns (Nb minimum, high K, Cs, Rb, Ba, Sr concentrations).
 
 

Literature

Babansky A.D., Pevzner M.M., Volynets A.O. (2006) Petrology, geochemistry and geodynamics of Holocene volcanism in the Elovka River basin (North Kamchatka). Volcanism and geodynamics. Abstracts of the 3rd All-Rissia symposium on volcanology and paleovolcanology, Ulan-Ude, September 5-8, 2006, pp.512-515.

Pevzner M.M. (2006) Holocene volcanism of Northern Kamchatka: The spatiotemporal aspect. Doklady of the Russian Academy of Sciences, Earth Sciences, Vol. 409A, No. 6, pp. 884887. Original Russian text published in Doklady Akademii Nauk, 2006, Vol. 409, No. 5, pp. 648651.

Siebert L, and Simkin T (2002-). Volcanoes of the World: an Illustrated Catalog of Holocene Volcanoes and their Eruptions. Smithsonian Institution, Global Volcanism Program, Digital Information Series, GVP-3, (http://www.volcano.si.edu/world/).