DOI: 10.1016/j.epsl.2017.11.010
Scopus记录号: 2-s2.0-85034048671
论文题名: Hot pressing in conduit faults during lava dome extrusion: Insights from Mount St. Helens 2004–2008
作者: Ryan A.G. ; Friedlander E.A. ; Russell J.K. ; Heap M.J. ; Kennedy L.A.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 482 起始页码: 171
结束页码: 180
语种: 英语
英文关键词: densification
; hot-pressing
; lava-dome
; permeability
; sintering
; volcanic-fault-gouge
Scopus关键词: Densification
; Domes
; Extrusion
; Hot pressing
; Mechanical permeability
; Porosity
; Sintering
; Volcanoes
; Confining pressures
; Diverse properties
; Elevated temperature
; Fault gouge
; Laboratory measurements
; Lava dome
; Solid state sintering
; Volcanic outgassing
; Pressing (forming)
; extrusion
; fault gouge
; hot spot
; lava dome
; permeability
; porosity
; sinter
; Cascade Range
; Mount Saint Helens
; United States
; Washington [United States]
英文摘要: Rhyodacitic volcanoes such as Mount St. Helens (MSH), Soufrière Hills, Mount Unzen and Mount Pelée erupt spines mantled by layers of magma-derived cataclasite and fault gouge. MSH produced seven lava spines from 2004–2008 composed of low-porosity, compositionally uniform, crystalline dacite. Dome extrusion was attended by continuous ‘drumbeat’ seismicity, derived from faulting along the conduit margin at 0.5–1 km depth, and evidenced by the enveloping gouge layers. We describe the properties of the gouge-derived fault rocks, including laboratory measurements of porosity and permeability. The gouge varies from unconsolidated powder to lithified low-porosity low-permeability fault rocks. We reconstruct the subsurface ascent of the MSH magma using published field observations and create a model that reconciles the diverse properties of the gouge with conditions in the conduit during ascent (i.e. velocity, temperature). We show lithification of the gouge to be driven by ‘hot pressing’ processes, wherein the combination of elevated temperature, confining pressure and dwell-time cause densification and solid-state sintering of the comminuted, crystal-rich (glass-poor) gouge. The degree of gouge lithification corresponds with residence time in the conduit such that well-lithified materials reflect extended times in the subsurface due to slower ascent rates. With this insight, we suggest that gouge competence can be used as a first-order estimate of lava ascent rates. Furthermore we posit gouge lithification, which reduces porosity and permeability, inhibits volcanic outgassing thereby increasing the potential for explosive events at spine-producing volcanoes. © 2017 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/110117
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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作者单位: Volcanology and Petrology Laboratory, Department of Earth and Ocean Sciences, University of British Columbia, 2020-2207 Main Mall, Vancouver, BC V6T 1Z4, Canada; Géophysique Expérimentale, Institut de Physique de Globe de Strasbourg, UMR 7516 CNRS, Université de Strasbourg/EOST, 5 rue René Descartes, Strasbourg cedex, 67084, France
Recommended Citation:
Ryan A.G.,Friedlander E.A.,Russell J.K.,et al. Hot pressing in conduit faults during lava dome extrusion: Insights from Mount St. Helens 2004–2008[J]. Earth and Planetary Science Letters,2018-01-01,482