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Along-arc variations in lithospheric mantle compositions in Kamchatka, Russia: First trace element data on mantle xenoliths from the Klyuchevskoy Group volcanoes

Ionov D.A., Bénard A., Plechov P.Yu., Shcherbakov V.D. (2013) Along-arc variations in lithospheric mantle compositions in Kamchatka, Russia: First trace element data on mantle xenoliths from the Klyuchevskoy Group volcanoes // Journal of Volcanology and Geothermal Research. Vol. 263, pp. 122 - 131. doi: 10.1016/j.jvolgeores.2012.12.022.

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Аннотация

Abstract We provide results of a detailed study of the first peridotite xenoliths of proven mantle origin reported from Bezymyanny volcano in the Klyuchevskoy Group, northern Kamchatka arc. The xenoliths are coarse spinel harzburgites made up mainly of Mg-rich olivine as well as subhedral orthopyroxene (opx) and Cr-rich spinel, and also contain fine-grained interstitial pyroxenes, amphibole and feldspar. The samples are unique in preserving the evidence for both initial arc mantle substrate produced by high-degree melt extraction and subsequent enrichment events. We show that the textures, modal and major oxide compositions of the Bezymyanny xenoliths are generally similar to those of spinel harzburgite xenoliths from Avacha volcano in southern Kamchatka. However, coarse opx from the Bezymyanny harzburgites has higher abundances of light and medium rare earth elements and other highly incompatible elements than coarse opx from the Avacha harzburgites. We infer that (1) the sub-arc lithospheric mantle beneath both Avacha and Bezymyanny (and possibly between these volcanoes) consists predominantly of harzburgitic melting residues, which experienced metasomatism by slab-related fluids or low-fraction, fluid-rich melts and (2) the degrees of metasomatism are higher beneath Bezymyanny. By contrast, xenolith suites from Shiveluch and Kharchinsky volcanoes 50–100 km north of the Klyuchevskoy Group include abundant cumulates and products of reaction of mantle rocks with silicate melts at high melt/rock ratios. The high melt flux through the lithospheric mantle beneath Shiveluch and Kharchinsky may be related to the asthenospheric flow around the northern edge of the sinking Pacific plate; lateral propagation of fluids in the mantle wedge south of the plate edge may contribute to metasomatism in the mantle lithosphere beneath the Klyuchevskoy Group volcanoes.
Тип объекта: Статья
Название: Along-arc variations in lithospheric mantle compositions in Kamchatka, Russia: First trace element data on mantle xenoliths from the Klyuchevskoy Group volcanoes
Язык: English
Издание: Journal of Volcanology and Geothermal Research
ISSN Print: 0377-0273
Ключевые слова: Mantle xenolith, Harzburgite, Metasomatism, Trace elements, Subduction, Island arc
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 > Авачинский
1 Вулканы > 1.1 Вулканы Курило-Камчатского региона > 1.1.1 Камчатка > Безымянный
Дополнительная информация: Magma System Response to Edifice Collapse
Разместивший пользователь: И.М. Романова
Дата размещения: 17 Дек 2015 06:44
Последнее изменение: 17 Дек 2015 06:44
URI: http://repo.kscnet.ru/id/eprint/2545

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