DOI: 10.1007/s00531-012-0810-3
Scopus记录号: 2-s2.0-84908567623
论文题名: Contrasting compositional trends of rocks and olivine-hosted melt inclusions from Cerro Negro volcano (Central America): implications for decompression-driven fractionation of hydrous magmas
作者: Portnyagin M.V. ; Hoernle K. ; Mironov N.L.
刊名: International Journal of Earth Sciences
ISSN: 14373254
出版年: 2014
卷: 103, 期: 7 起始页码: 1963
结束页码: 1982
语种: 英语
英文关键词: Central America
; Cerro Negro
; CO2
; Crystallization
; Decompression
; Degassing
; H2O
; Melt inclusions
Scopus关键词: decompression
; fractional crystallization
; fractionation
; host rock
; igneous geochemistry
; island arc
; magma
; melt inclusion
; olivine
; tephra
; volcanic eruption
; Cerro Negro Volcano
; Leon [Nicaragua]
; Nicaragua
英文摘要: Melt inclusions in olivine Fo83–72 from tephras of 1867, 1971 and 1992 eruptions of Cerro Negro volcano represent a series of basaltic to andesitic melts of narrow range of MgO (5.6–8 wt %) formed by ~46 wt % fractional crystallization of olivine (~6 wt %), plagioclase (~27 wt %), pyroxene (~13 wt %) and magnetite (<1 wt %) from primitive basaltic melt (average SiO2 = 49 wt %, MgO = 7.6 wt %, H2O = 6 wt %) as it ascended to the surface from the depth of about 14 km. The crystallization occurred at increasing liquidus temperature from 1,050 to 1,090 °C in the pressure range from 400 to 50 MPa and was induced by release of mixed H2O–CO2 fluid from the melt at decreasing pressure. Matrix glass compositions fall at the high-Si end of the melt inclusion trend and represent the final stage of melt crystallization during and after eruption. The bulk compositions of erupted Cerro Negro magmas (tephras and lavas) range from high- to low-MgO (3–10 wt %) basalts, which form a compositional array crossing the trend of melt inclusions so that virtually no rock from Cerro Negro has composition akin to true melt represented by the inclusions. The variations of the bulk magma (rocks) and melt (melt inclusions) compositions can be generated in a dyke connecting a deep primitive magma reservoir with the Cerro Negro edifice. While the melt inclusions represent the compositional trend of instantaneous melts along the magma pathway at decreasing pressure and H2O content, occurrence of low-Mg to high-Mg basalts reflects the process of phenocryst re-distribution in progressively evolving melt. The crystallization scenario is anticipated to operate everywhere in dykes feeding basaltic volcanoes and can explain the predominance of plagioclase-rich high-Al basalts in island arc as well as typical compositional variations of magmas during single eruptions. © 2012, Springer-Verlag. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84908567623&doi=10.1007%2fs00531-012-0810-3&partnerID=40&md5=e9ec64de04e6f0c6fa1d901f59b15163
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/70388
Appears in Collections: 影响、适应和脆弱性 气候减缓与适应
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作者单位: GEOMAR, Helmholtz Centre for Ocean Research, Wischhofstrasse 1-3, Kiel, Germany; V. I. Vernadsky Institute of Geochemistry and Analytical Chemistry, GEOKHI RAS, Kosygin str. 19, Moscow, Russian Federation
Recommended Citation:
Portnyagin M.V.,Hoernle K.,Mironov N.L.. Contrasting compositional trends of rocks and olivine-hosted melt inclusions from Cerro Negro volcano (Central America): implications for decompression-driven fractionation of hydrous magmas[J]. International Journal of Earth Sciences,2014-01-01,103(7)