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churikova

HR: 1330h
AN: V42D-1062
TI: Kizimen Volcano: An Unzen-like Magma System in Kamchatka
AU: * Churikova, T
AF: Institute of Volcanology Geology and Geochemistry, 9 Piip Ave. , Petropavlovsk, 683006 Russian Federation
AU: * Churikova, T
AF: Goettinger Zentrum Geowissenschaftern, Abt. Geochemie, Goldschmidstr.1, Universitaet Goettinger, Goettinger, 37077 Germany
AU: Ivanov, B
AF: Institute of Volcanology Geology and Geochemistry, 9 Piip Ave. , Petropavlovsk, 683006 Russian Federation
AU: Eichelberger, J
EM: [email protected]
AF: Alaska Volcano Observatory, Geophysical Institute, University of Alaska Fairbanks, Fairbanks, AK 99775-7320 United States
AU: Trusov, S
AF: Institute of Volcanology Geology and Geochemistry, 9 Piip Ave. , Petropavlovsk, 683006 Russian Federation
AU: Gardner, J
AF: Alaska Volcano Observatory, Geophysical Institute, University of Alaska Fairbanks, Fairbanks, AK 99775-7320 United States
AU: Belousov, A
AF: Institute of Volcanology Geology and Geochemistry, 9 Piip Ave. , Petropavlovsk, 683006 Russian Federation
AU: Belousov, A
AF: GEOMAR, Wischhofstr,1-3, Kiel, 2040048 Germany
AU: Browne, B
AF: Alaska Volcano Observatory, Geophysical Institute, University of Alaska Fairbanks, Fairbanks, AK 99775-7320 United States
AU: Izbekov, P
AF: Alaska Volcano Observatory, Geophysical Institute, University of Alaska Fairbanks, Fairbanks, AK 99775-7320 United States
AU: Werner, G
AF: Goettinger Zentrum Geowissenschaftern, Abt. Geochemie, Goldschmidstr.1, Universitaet Goettinger, Goettinger, 37077 Germany
AB: Kizimen Volcano is a Holocene lava and dome complex from basaltic andesite to dacite composition situated on the eastern edge of the Central Kamchatka Depression (CKD) and midway between volcanoes of the eastern front (EVF) and of CKD. All lavas are horblende-bearing mid-potassic of the calcalkaline series. They differ from two-pyroxene basalts and andesites of ancestral, Pleistocene, Kizimenok Volcano in showing greater geochemical and petrological evidence of modification by crustal processes. Prominent characteristics of the rocks are large phenocrysts of plagioclase and hornblende co-existing with olivine and orthopyroxene as well as abundant cognate mafic enclaves of more primitive (basaltic to basaltic andesitic) composition. Trace element geochemistry is typical of island arc volcanism (IAB). Sr, Nd, Pb isotope systematics lie well within normal Kamchatka Volcanoes and close to MORB. Phenocrysts show extreme disequilibrium in terms of magnesium number of mafic phases (olivine, pyroxene), presence of quartz, and coexistence of apatite and sulfide. Enclaves are both fractionated compared to primary mantle melt and are contaminated by incorporation of more acidic material from the host. Similarly, the host is contaminated by basic debris from enclaves. This interaction likely occurs by frequent recharge of mantle magma to a mid to upper crustal chamber. Despite pervasive evidence of magma mingling, the fundamental geochemical signature of subduction origin remains clear. Thus, the apparently crustal admixed silicic component is likely of cogenetic plutonic origin. Kizimen exhibits some remarkable similarities to Unzen Volcano in Japan. 1. Repeated extrusion of hybrid dacite domes and more basic lavas from the summit region. 2. Thick block-and-ash aprons to domes but relative paucity of tephras, despite apparent high water content of the magma. 3. Close association with an active graben structure. 4. Nearly identical petrologic characteristics indicative of shallow interaction of contrasting magmas. An age of less than 1,000 years for the youngest flows (from lichenometry) and presence of vigorous superheated fumaroles indicate the likelihood of future, Unzen-like eruptions.
DE: 1040 Isotopic composition/chemistry
DE: 1065 Trace elements (3670)
DE: 8439 Physics and chemistry of magma bodies
SC: V
MN: 2001 AGU Fall Meeting