Репозиторий Института вулканологии и сейсмологии ДВО РАН
Институт вулканологии и сейсмологии ДВО РАН
Поиск
Просмотр
Объекты ИВиС
Статистика
Помощь
Ссылки

Petrological and geochemical evolution of the Tolbachik volcanic massif, Kamchatka, Russia

Churikova Tatiana G., Gordeychik Boris N., Iwamori Hikaru, Nakamura Hitomi, Ishizuka Osamu, Nishizawa Tatsuji, Haraguchi Satoru, Miyazaki Takashi, Vaglarov Bogdan S. (2015) Petrological and geochemical evolution of the Tolbachik volcanic massif, Kamchatka, Russia // Journal of Volcanology and Geothermal Research. Vol. 307, pp. 156 - 181. doi: 10.1016/j.jvolgeores.2015.10.026.

[thumbnail of Churikova_2015 JVGR Tolbachik Evolution.pdf]
Предварительный просмотр
Полный текст
Churikova_2015 JVGR Tolbachik Evolution.pdf

Скачать (4MB) | Предварительный просмотр
[thumbnail of Churikova_2015 JVGR Tolbachik Evolution e-Table 1 (Rev. 09-03-2017).xlsx] Таблица
Churikova_2015 JVGR Tolbachik Evolution e-Table 1 (Rev. 09-03-2017).xlsx

Скачать (95kB)

Аннотация

Data on the geology, petrography, and geochemistry of Middle–Late-Pleistocene rocks from the Tolbachik volcanic massif (Kamchatka, Klyuchevskaya group of volcanoes) are presented and compared with rocks from the neighboring Mount Povorotnaya, Klyuchevskaya group basement, and Holocene–historical Tolbachik monogenetic cones. Two volcanic series of lavas, middle-K and high-K, are found in the Tolbachik massif. The results of our data analysis and computer modeling of crystallization at different P–T–H2O–fO2 conditions allow us to reconstruct the geochemical history of the massif. The Tolbachik volcanic massif started to form earlier than 86 ka based on K–Ar dating. During the formation of the pedestal and the lower parts of the stratovolcanoes, the middle-K melts, depleted relative to NMORB, fractionated in water-rich conditions (about 3 of H2O). At the Late Pleistocene–Holocene boundary, a large fissure zone was initiated and the geodynamical regime changed. Upwelling associated with intra-arc rifting generated melting from the same mantle source that produced magmas more enriched in incompatible trace elements and subduction components; these magmas are high-K, not depleted relative to N-MORB melts with island arc signatures and rift-like characteristics. The fissure opening caused degassing during magma ascent, and the high-K melts fractionated at anhydrous conditions. These high-K rocks contributed to the formation of the upper parts of stratovolcanoes. At the beginning of Holocene, the high-K rocks became prevalent and formed cinder cones and associated lava fields along the fissure zone. However, some features, including 1975–1976 Northern Breakthrough, are represented by middle-K high-Mg rocks, suggesting that both middle-K and high-K melts still exist in the Tolbachik system. Our results show that fractional crystallization at different water conditions and a variably depleted upper mantle source are responsible for all observed variations in rocks within the Tolbachik volcanic massif. Sr–Nd isotopes are consistent with 2–4 crustal assimilation during formation of the pedestal and stratovolcanoes, while the young lava fields do not show evidence of crustal assimilation. Major and trace element data coupled with K–Ar dating provide strong evidence that Mount Povorotnaya, located in 8 km northeast of Plosky Tolbachik, is an old block of the Tolbachik massif pedestal and for the moment it is the oldest (306 ka) known object in Klyuchevskaya group of volcanoes.
Тип объекта: Статья
Название: Petrological and geochemical evolution of the Tolbachik volcanic massif, Kamchatka, Russia
Язык: English
Издание: Journal of Volcanology and Geothermal Research
ISSN Print: 0377-0273
Ключевые слова: Central Kamchatka Depression, Klyuchevskaya group, Tolbachik volcanic massif, Subduction, Geochemistry, Fractional crystallization
Тематика: 3 ГРНТИ - Государственный рубрикатор научно-технической информации > 38 ГЕОЛОГИЯ > 38.37 Петрография > 38.37.25 Вулканология
1 Вулканы > 1.1 Вулканы Курило-Камчатского региона > 1.1.1 Камчатка > Плоский Толбачик
Дополнительная информация: SI: 2012-13 Tolbachik eruption
Разместивший пользователь: снс Татьяна Чурикова
Дата размещения: 15 Дек 2015 02:17
Последнее изменение: 22 Май 2017 09:36
URI: http://repo.kscnet.ru/id/eprint/2532

Действия с объектом

Редактировать (только для владельца) Редактировать (только для владельца)