DOI: 10.1016/j.epsl.2020.116596
论文题名: Taking the pulse of volcanic eruptions using plagioclase glomerocrysts
作者: McCarthy A. ; Chelle-Michou C. ; Blundy J.D. ; Vonlanthen P. ; Meibom A. ; Escrig S.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2020
卷: 552 语种: 英语
中文关键词: nano-SIMS
; orbicules and comb layering
; plagioclase glomerocryst
; rapid crystal growth
; Tolbachik volcano
; volatile-fluxing
英文关键词: Analytical geochemistry
; Carbon dioxide
; Degassing
; Feldspar
; Structural geology
; Textures
; Zoning
; Compositional evolution
; Compositional zoning
; Dynamic environments
; Monitoring signals
; Oscillatory zoning
; Volatile abundances
; Volatile elements
; Volcanic eruptions
; Volcanoes
; crystal
; crystallization
; degassing
; magma
; mass spectrometry
; melt inclusion
; olivine
; plagioclase
; volcanic eruption
; Kamchatka
; Russian Federation
; Tolbachik Volcano
英文摘要: Crystallization timescales in subvolcanic systems and the consequences of interaction between ascending magmas and gases remain largely unconstrained, as do links between these processes and monitoring signals at restless volcanoes. We apply diffusion chronometry to radially-oriented plagioclase and associated olivine in a glomerocryst from Tolbachik volcano (Kamchatka, Russia) to elucidate such processes. We show that cm-size glomerocrysts grow in a few days prior to, or during, eruption. Melt inclusions from these glomerocrysts show no compositional evolution during crystallization, implying growth in a melt-rich and dynamic environment. Volatile elements in melt inclusions show significant variability, with increasing CO2 as H2O decreases. This behaviour is inconsistent with normal degassing processes, and more likely reflects CO2-fluxing. On the basis of short residence timescales of glomerocrysts and sharp changes in melt inclusion volatile abundances, we propose that rapid (pre-)eruptive crystallization is controlled by rhythmic fluxing of magmatic H2O and CO2 through the sub-volcanic conduit. This implies that compositional zoning in plagioclase, from resorption textures to oscillatory zoning, record short-term CO2- and H2O-fluxing episodes, consistent with strombolian eruption dynamics. We propose that volcanic glomerocrysts represent the counterpart of vertical igneous layering (or comb layering) in shallow plutons. Magmatic layering and glomerocrysts dominated by radial plagioclase offer novel ways of targeting short-term crystallization and degassing processes in subvolcanic systems. © 2020 The Author(s) Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/165154
Appears in Collections: 气候变化与战略
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作者单位: School of Earth Sciences, Wills Memorial Building, University of Bristol, United Kingdom; Department of Earth Sciences, ETH, Zürich, Switzerland; Department of Earth Sciences, University of Oxford, United Kingdom; Institut des Science de la Terre, University of Lausanne, Switzerland; Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering, Ecole Polytechnique Fédérale de Lausanne, Switzerland; Center for Advanced Surface Analysis, Institute of Earth Sciences, University of Lausanne, Switzerland
Recommended Citation:
McCarthy A.,Chelle-Michou C.,Blundy J.D.,et al. Taking the pulse of volcanic eruptions using plagioclase glomerocrysts[J]. Earth and Planetary Science Letters,2020-01-01,552