DOI: 10.1016/j.epsl.2020.116500
论文题名: Glacial pumping of a magma-charged lithosphere: A model for glaciovolcanic causality in magmatic arcs
作者: Wilson A.M. ; Russell J.K.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2020
卷: 548 语种: 英语
中文关键词: causality
; Cordilleran Ice Sheet
; deglaciation
; eruption-rate
; glaciovolcanism
; volcanic arc
英文关键词: Climate models
; Hydraulic structures
; Monte Carlo methods
; Stress analysis
; Unloading
; Volcanoes
; British Columbia , Canada
; Deviatoric stress
; Dike propagation
; Extensional stress
; Glacial loadings
; Last deglaciation
; Tectonic settings
; Thin-plate bending
; Glacial geology
; glaciotectonics
; lithosphere
; magmatic differentiation
; subduction
; tectonic setting
; volcanic eruption
; volcanism
; British Columbia
; Canada
英文摘要: Glacial loading and unloading can influence the rates and timing of magmatism in tectonic settings where the lithosphere is relatively thin and hot. In continental arcs, where the lithosphere is substantially thicker, nominal loading by surface glaciers is unlikely to affect the production of subduction-related magmas. However, geologic evidence suggests that a causal linkage between volcanism and glaciations in arcs does exist. The last deglaciation of the Garibaldi volcanic belt in southwestern British Columbia, Canada saw a ∼5-fold volumetric increase in volcanism over the mean Pleistocene (background) rate that coincided with ∼400 m of rapid postglacial crustal uplift. Here, we use a cylindrical, thin plate bending approximation to calculate the horizontally oriented stresses developed in the crust during glacial loading/unloading (up to ±12 MPa). The distribution of compressive and extensional stresses is shown to modulate magma transport and storage by facilitating or suppressing magma ascent by dike propagation. We use Monte Carlo simulations to track the depth of upward migrating magma bodies in the crust over a single glacial cycle (i.e., during crustal depression and rebound). During loading, volcanism is suppressed as magma becomes trapped by compressive deviatoric stress in the upper part of the crust. During unloading, relaxation of this stress acts to release accumulated magma from the upper crust and causes an increase in eruption rate immediately following deglaciation. This model of “glacial pumping” of a magma-charged lithosphere suggests a causal linkage between volcanism and glaciation in volcanic arcs that explains the persistent observation that the volume and timing of volcanism is correlated with the major climate cycles. © 2020 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/165345
Appears in Collections: 气候变化与战略
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作者单位: Volcanology & Petrology Laboratory, Earth Ocean & Atmospheric Science, University of British Columbia, 2020 – 2207 Main Mall, BC, Vancouver, V6T 1Z4, Canada
Recommended Citation:
Wilson A.M.,Russell J.K.. Glacial pumping of a magma-charged lithosphere: A model for glaciovolcanic causality in magmatic arcs[J]. Earth and Planetary Science Letters,2020-01-01,548