Fig. 1

Fig. 2

Fig. 3


Fig. 4


Fig. 5


Fig. 6


Fig. 7

No eruptions from the Sredinny Range volcanoes have been mentioned in the historical records (last 200-300 years). This is likely the reason for a widely accepted opinion that Sredinny Range volcanism either is dying or is already dead. In addition, existence of recent volcanism north of the presumed northern boundary of the subducting Pacific plate, beyond an active subduction zone, does not fit into dominating tectonic models (e.g. Park et al., 2002). The first catalogue of the Sredinny Range volcanoes (Ogorodov et al.,1972), however, described many Holocene volcanoes extending as far as 58.37°N. These preliminary age estimates were based mainly on "freshness" of the volcanic topography. Recent studies based on tephrochronology and ¹⁴C dating (Pevzner, 2006) have allowed to identify and document the following volcanic centers, which are likely the northernmost of the Holocene volcanoes in Kamchatka.

The northernmost of the Kamchatka Holocene volcanoes known so far is a monogenic cinder cone Tobeltsen (58°15′N, 160°44′E, elev. 831.8 m) and an associated lava flow descending to the Voyampolka River valley (Fig. 1). Erupted products are medium-K basalt. Based on tephrochronology and radiocarbon dating, Tobeltsen cone formed ~3.5 ka BP (Fig. 7).

Next Holocene volcano, located 11 km SSE of Tobeltsen, is a small, previously nameless cinder cone called X Cone by Maria Pevzner (2006) (Figs. 2 and 3; 58°10′N, 160°48′E; elev. 2127.5 m). X Cone sits in the axial part of the Sredinny Range and is composed of medium-K basalt. Based on tephrochronology and radiocarbon dating, the cone formed about 4.0 ka BP (Fig. 7). 

Spokoiny volcano (Figs.4 and 5; 58°08′ N, 160°49′E; elev. 2170.6 m; GVP number 1000-671) is located on the divide of the Levaia Nachika and Kutina rivers. It was called Kutina volcano by Ogorodov et al. (1972), but modern maps call it Spokoiny that means "quiet" in Russian. The volcano was active repeatedly in the early and middle Holocene; the most recent of its five explosive eruptions, identified so far, took place ~5.4 ka BP. Erupted products are medium to high-K dacite-rhyolite.

Nylgimelkin (Fig. 6; 57°58′ N, 160°39′E, elev. 1621.0 m; GVP number 1000-65) is a small shield-like volcano crowned by a couple of cinder cones. Based on the tephrochronology and radiocarbon dating, it formed ~5.5 ka BP. The volcano was mentioned as Atlasov volcano by Ogorodov et al. (1972). Erupted products are medium-K basalt.

Cinders of Tobeltsen,  X Cone and Nylgimelkin form distinct layers in the soil-pyroclastic sequence and can all be seen together in a number of sections (Fig. 7).

Literature

Ogorodov N. V., Kozhemyaka N. N., Vazheevskaya A. A., and A. Ogorodova (1972) Volcanoes and Quaternary Volcanism in the Sredinnyi Ridge of Kamchatka. Nauka, Moscow [in Russian]

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. 884–887. Original Russian text published in Doklady Akademii Nauk, 2006, Vol. 409, No. 5, pp. 648–651.

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/).