气候变化领域集成服务门户(CCPortal): Reactivation of Magma Pathways: Insights From Field Observations, Geochronology, Geomechanical Tests, and Numerical Models

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DOI	10.1029/2020JB021477
	Reactivation of Magma Pathways: Insights From Field Observations, Geochronology, Geomechanical Tests, and Numerical Models
	Thiele S.T.; Cruden A.R.; Zhang X.; Micklethwaite S.; Matchan E.L.
发表日期	2021
ISSN	21699313
卷号	126 期号:5
英文摘要	Field observations and unmanned aerial vehicle surveys from Caldera Taburiente (La Palma, Canary Islands, Spain) show that pre-existing dykes can capture and re-direct younger ones to form multiple dyke composites. Chill margins suggest that the older dykes were solidified and cooled when this occurred. In one multiple dyke example, an 40Ar/39Ar age difference of 200 kyr was determined between co-located dykes. Petrography and geomechanical measurements (ultrasonic pulse and Brazilian disc tests) show that a microscopic preferred alignment of plagioclase laths and sheet-like structures formed by non-randomly distributed vesicles give the solidified dykes anisotropic elastic moduli and fracture toughness. We hypothesize that this anisotropy led to the development of margin-parallel joints within the dykes, during subsequent volcanic loading. Finite element models also suggest that the elastic contrast between solidified dykes and their host rock elevated and re-oriented the stresses that governed subsequent dyke propagation. Thus, the margin-parallel joints, combined with local concentration and rotation of stresses, favored the deflection of subsequent magma-filled fractures by up to 60° to form the multiple dykes. At the edifice scale, the capture and deflection of active intrusions by older ones could change the organization of volcanic magma plumbing systems and cause unexpected propagation paths relative to the regional stress. We suggest that reactivation of older dykes by this mechanism gives the volcanic edifice a structural memory of past stress states, potentially encouraging the re-use of older vents and deflecting intrusions along volcanic rift zones or toward shallow magma reservoirs. © 2021. The Authors.
英文关键词	basalt Ar-Ar dating; Canary Islands; elastic anisotropy; fracture deflection; mechanical discontinuity; multiple dyke; quaternary; reactivation
语种	英语
来源期刊	Journal of Geophysical Research: Solid Earth
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/187121
作者单位	Helmholtz Institute Freiberg for Resource Technology, Helmholtz-Zentrum Dresden-Rossendorf, Freiberg, Germany; School of Earth, Atmosphere and Environment, Monash University, Melbourne, VIC, Australia; SCT Operations Pty Ltd, Wollongong, NSW, Australia; Sustainable Minerals Institute, University of Queensland, Brisbane, QLD, Australia; School of Earth Sciences, The University of Melbourne, Parkville, VIC, Australia
推荐引用方式 GB/T 7714	Thiele S.T.,Cruden A.R.,Zhang X.,et al. Reactivation of Magma Pathways: Insights From Field Observations, Geochronology, Geomechanical Tests, and Numerical Models[J],2021,126(5).
APA	Thiele S.T.,Cruden A.R.,Zhang X.,Micklethwaite S.,&Matchan E.L..(2021).Reactivation of Magma Pathways: Insights From Field Observations, Geochronology, Geomechanical Tests, and Numerical Models.Journal of Geophysical Research: Solid Earth,126(5).
MLA	Thiele S.T.,et al."Reactivation of Magma Pathways: Insights From Field Observations, Geochronology, Geomechanical Tests, and Numerical Models".Journal of Geophysical Research: Solid Earth 126.5(2021).