Research output: Contribution to journal › Conference article › peer-review
Magma storage constrains by compositional zoning of plagioclase from dacites of the caldera forming eruptions of Vetrovoy Isthmus and Lvinaya Past' Bay (Iturup Island, Kurile Islands). / Maksimovich, I. A.; Smirnov, S. Z.; Kotov, A. A. et al.
In: IOP Conference Series: Earth and Environmental Science, Vol. 110, No. 1, 012015, 03.01.2018.Research output: Contribution to journal › Conference article › peer-review
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TY - JOUR
T1 - Magma storage constrains by compositional zoning of plagioclase from dacites of the caldera forming eruptions of Vetrovoy Isthmus and Lvinaya Past' Bay (Iturup Island, Kurile Islands)
AU - Maksimovich, I. A.
AU - Smirnov, S. Z.
AU - Kotov, A. A.
AU - Yu Timina, T.
AU - Shevko, A. V.
N1 - Publisher Copyright: © Published under licence by IOP Publishing Ltd.
PY - 2018/1/3
Y1 - 2018/1/3
N2 - The Vetrovoy Isthmus and the Lvinaya Past' Bay on the Iturup island (Kuril island arc) are the results of large Plinian eruptions of compositionally similar dacitic magmas. This study is devoted to a comparative analysis of the storage and crystallization conditions for magma reservoirs, which were a source of large-scale explosive eruptions. The plagioclase is most informative mineral in studying of the melt evolution. The studied plagioclases possess a complex zoning patterns, which are not typical for silicic rocks in island-arc systems. It was shown that increase of Ca in the plagioclase up to unusually high An95 is related to increase of H2O pressure in both volcanic magma chambers. The study revealed that minerals of the Vetrovoy Isthmus and Lvinaya Past' crystallized from compositionally similar melts. Despite the compositional similarity of the melts, the phenocryst assemblage of the Lvinaya Past' differs from the Vetrovoy Isthmus by the presence of the amphibole, which indicates that the pressure in the magmatic chamber exceeded 1-2 kbar at a 4-6 wt. % of H2O in the melt. The rocks of the Vetrovoy Isthmus do not contain amphibole phenocrysts, but melt and fluid inclusions assemblages in plagioclase demonstrate that the magma degassed in the course of evolution. This is an indication that the pressure did not exceed significantly 1-2 kbar.
AB - The Vetrovoy Isthmus and the Lvinaya Past' Bay on the Iturup island (Kuril island arc) are the results of large Plinian eruptions of compositionally similar dacitic magmas. This study is devoted to a comparative analysis of the storage and crystallization conditions for magma reservoirs, which were a source of large-scale explosive eruptions. The plagioclase is most informative mineral in studying of the melt evolution. The studied plagioclases possess a complex zoning patterns, which are not typical for silicic rocks in island-arc systems. It was shown that increase of Ca in the plagioclase up to unusually high An95 is related to increase of H2O pressure in both volcanic magma chambers. The study revealed that minerals of the Vetrovoy Isthmus and Lvinaya Past' crystallized from compositionally similar melts. Despite the compositional similarity of the melts, the phenocryst assemblage of the Lvinaya Past' differs from the Vetrovoy Isthmus by the presence of the amphibole, which indicates that the pressure in the magmatic chamber exceeded 1-2 kbar at a 4-6 wt. % of H2O in the melt. The rocks of the Vetrovoy Isthmus do not contain amphibole phenocrysts, but melt and fluid inclusions assemblages in plagioclase demonstrate that the magma degassed in the course of evolution. This is an indication that the pressure did not exceed significantly 1-2 kbar.
KW - PLEISTOCENE
KW - EQUILIBRIA
KW - KAMCHATKA
KW - EVOLUTION
UR - http://www.scopus.com/inward/record.url?scp=85040711521&partnerID=8YFLogxK
U2 - 10.1088/1755-1315/110/1/012015
DO - 10.1088/1755-1315/110/1/012015
M3 - Conference article
AN - SCOPUS:85040711521
VL - 110
JO - IOP Conference Series: Earth and Environmental Science
JF - IOP Conference Series: Earth and Environmental Science
SN - 1755-1307
IS - 1
M1 - 012015
ER -
ID: 12081190