Nechaeva T.B., Kochegura V.V., Zubov A.G. Studies of secular paleomagnetic variations in Kamchatka using Holocene tephra // Journal of Volcanology and Seismology. 1984. V. 5. № 2. P. 213-218.
Analysis of paleomagnetic variations along parallel sections across the Holocene soil-pyroclastic cover of Ма1уĭ Semyachek Volcano in Kamchatka has shown that directions of magnetization were similar during а period of 350 — 6000 В.P. This proves that magnetization is primary and applicable for reconstruction of the history of the Earth's magnetic field. Paleomagnetic variations that occurred in the interval of 1000 — 4000 В.P. have been investigated in the contemporaneous tephra section of Klyuchevskoĭ Volcano 240 km to the north.
It is known that since some of the tephra horizons may be missing in this section owing to specific conditions of tephra deposition, а more detailed knowledge of paleomagnetic variations requires the study of two or more parallel sections.
Проведено сравнение палеовариаций магнитного поля Земли, полученных по параллельным разрезам голоценового почвенно-пирокластического чехла вулкана Малый Семячик на Камчатке. Показано, что в интервале возраста 300 — 6000 лет назад наблюдается подобие изменений направления остаточной намагниченности подтверждающее первичность этой намагниченности и пригодность ее для реконструкции истории геомагнитного поля. Палеовариации, выделенные для интервала 1000 — 4000 лет назад, прослежены в одновозрастных слоях в 240 км к северу, в разрезе тефры Ключевского вулкана.
Выяснено, что вследствие связанной со спецификой формирования отложений тефры возможности выпадения из разрезов отдельных горизонтов для получения достаточно детальной картины палеовариаций необходимо изучение двух или более параллельных разрезов.
Рис. 6, библ. 3 назв.
Neill Owen K., Hammer Julia E., Izbekov Pavel E., Belousova Marina G., Belousov Alexander B., Clarke Amanda B., Voight Barry Influence of pre-eruptive degassing and crystallization on the juvenile products of laterally directed volcanic explosions // Journal of Volcanology and Geothermal Research. 2010. V. 198. № 1-2. P. 264-274. doi:10.1016/j.jvolgeores.2010.09.011.
Nemoto T. Geologic and petrologic study of the Central Kurile Islands, VI - Dzigoku Volcano, Urup Island // Bulletin of the Volcanological Society of Japan. 1937. V. 3. № 2.
Nishizawa T., Nakamura Hitomi, Churikova T., Gordeychik B., Ishizuka Osamu, Haraguchi Satoru, Miyazaki Takashi, Vaglarov Bogdan S., Ueki K., Toyama C., Iwamori Hikaru Geochemistry of high-Mg andesitic rocks in NE Kamchatka // V.M. Goldschmidt Conference, Yokohama, Japan, 26 June - 1 July 2016. Program and Abstracts. 2016. P. 2295
The northeast Kamchatka Peninsula is characterized by unique tectonic regimes: (i) the triple junction ~30 km off the east coast , (ii) subduction of the Emperor Seamount Chain , and (iii) possible asthenospheric flow between the mantle wedge and the sub-slab mantle via the edge of subducted Pacific slab . Within this area, a monogenetic volcanic group occurs along the east coast, including high-Mg andesitic rocks and relatively primitive basalts (East Cones, EC ). We have conducted geochemical studies of the EC lavas, with bulk rock major and trace elements, Sr-Nd isotopic compositions, and K-Ar and Ar-Ar ages, based on which a possible contribution of subducted seamounts and its relation to the tectonic setting are discussed.
The elemental and isotopic compositions indicate that the lavas from individual cones have distinct mantle sources with different amounts and/or compositions of slab-derived fluids. Based on mass balance, water content and melting phase relations, we estimate the melting P-T conditions to be ~1200 ℃ at 1.5 GPa, while the slab surface temperature is 620 – 730 ℃ (at 50-80 km depth). The Sr-Nd isotopic compositions is close to Late Cretaceous Emperor Seamount Chain, especially Detroit . The K-Ar and Ar-Ar ages of the Middle to Late Pleistocene are consistent with the present tectonic setting after 2 Ma .
These results suggest that the EC lavas including high-Mg andesite and basalt were generated by mantle flux-melting induced by dehydration of a subducted seamount inheriting a local thermal anomaly [7, 8]
Nishizawa Tatsuji, Nakamura Hitomi, Churikova T., Gordeychik B., Ishizuka Osamu, Iwamori Hikaru Genesis of Quaternary volcanism of high-Mg andesitic rocks in the northeast Kamchatka Peninsula // Japan Geoscience Union Meeting. 22-26 May 2016, Makuhari, Messe. 2016. P. SVC48-02.
Arc magmatism is a product of subduction factory, involving thermal and chemical interactions
between a subducted slab as a material input and mantle wedge as a processing factory. In turn, the
compositions of arc magma provide invaluable information concerning the material input and the
interactions. The northeast Kamchatka Peninsula is an ideal field to examine such interactions and
relationships, being characterized by (1) subduction of the Emperor Seamount Chain (Davaille and
Lees, 2004), and (2) possible material and thermal interaction among the subducted slab, the
overlying mantle wedge and the sub-slab mantle via the edge of subducted Pacific slab (Portnyagin
and Manea, 2008). Within this area, a monogenetic volcanic group occurs along the east coast,
including high-Mg andesitic rocks and relatively primitive basalts (East Cones, EC (Fedorenko,
1969)). We have conducted geochemical studies of the EC lavas, with bulk rock major and trace
elements, and K-Ar and Ar-Ar ages, based on which a possible contribution of subducted seamounts
and its relation to the tectonic setting are discussed.
The elemental compositions indicate that the lavas from individual cones have distinct mantle
sources with different amounts and/or compositions of slab-derived fluids. Based on mass balance,
water content and melting phase relations, we estimate the melting P-T conditions to bet ~1200 ℃
at 1.5 GPa, while the slab surface temperature is 620 –730 ℃ (at 50-80 km depth). Compared with
the southern part of Kamchatka, the slab surface temperature beneath EC seems to be high due to the
thinner Pacific slab associated with the seamount chain and/or the plate rejuvenation from a mantle
plume impact (Davaille and Lees, 2004; Manea and Manea, 2007).
The K-Ar and Ar-Ar ages of the Middle Pleistocene are consistent with the tephrochronological
study (Uspensky and Shapiro, 1984) and the present tectonic setting after 2 Ma (Lander and Shapiro,
2007). The high-Mg andesite with the highest SiO2 content in the EC lavas shows the oldest age
(0.73 ±0.06 Ma) within not only EC but also the northeast part of Kamchatka (e.g., Churikova et
al., 2015, IAVCEI). On the other hand, the rest of EC lava samples show relatively younger ages to
0.18 ±0.07 Ma. These results suggest that the EC lavas including high-Mg andesite and basalt were
generated by mantle flux-melting induced by dehydration of a subducted seamount inheriting a local
thermal anomaly (Nishizawa et al., 2014, JpGU; 2015, JpGU).
Ozerov A., Ispolatov I., Lees J. Modeling Strombolian eruptions of Karymsky volcano, Kamchatka, Russia // Journal of Volcanology and Geothermal Research. 2003. V. 122. № 3–4. P. 265 - 280. doi: 10.1016/S0377-0273(02)00506-1.
A model is proposed to explain temporal patterns of activity in a class of periodically exploding Strombolian-type andesite volcanoes. These patterns include major events (explosions) which occur every 3–30 min and subsequent tremor with a typical period of 1 s. This two-periodic activity is thought to be caused by two distinct mechanisms of accumulation of the elastic energy in the moving magma column: compressibility of the magma in the conduit and viscoelastic response of the almost solid magma plug on the top. A release of the elastic energy occurs during a stick–slip dynamic phase transition in a boundary layer along the walls of the conduit; this phase transition is driven by the shear stress accumulated in the boundary layer. The intrinsic hysteresis of this first-order phase transition explains the long periods of inactivity in the explosion cycle. Temporal characteristics of the model are found to be qualitatively similar to the acoustic and seismic signals recorded at Karymsky volcano in Kamchatka.
Ozerov A., Lees J., Ispolatov J. Long and Short Term Periodic Activity at Karymsky Volcano // AGU Spring Meeting 1999. Eos Trans. AGU, xx (xx), Spring Meet. Suppl., Abstract. Boston, Massachusetts: AGU. 1999. P. V11D-09.