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DOI	10.1016/j.epsl.2021.117080
	Crustal folds alter local stress fields as demonstrated by magma sheet — Fold interactions in the Central Andes
	Clunes M.; Browning J.; Cembrano J.; Marquardt C.; Gudmundsson A.
发表日期	2021
ISSN	0012821X
卷号	570
英文摘要	For magma chambers to form or volcanic eruptions to occur magma must propagate through the crust as dikes, inclined sheets and sills. Most models that investigate magma paths assume the crust to be either homogeneous or horizontally layered, often composed of rocks of contrasting mechanical properties. In regions that have experienced orogenesis, like the Andes, the crust has been deformed over several million years, resulting in rock layers that are commonly folded and steeply dipping. The assumption of homogeneous properties or horizontal layering then does not capture all of the potential magma path-crustal interactions. Here we tackle this problem by determining the effect of a crust made of steeply inclined layers in which sills and inclined sheets are emplaced. We combine field observations from a sill emplaced in the core of an anticlinal fold at El Juncal in the Chilean Central Andes, including lithologies, sill and fold limbs attitude, length and thickness with a suite of finite element method models to explore the mechanical interactions between inclined layers and magma paths. Our results demonstrate that the properties of the host rock layers as well as the contacts between the layers and the geometry of crustal structures all play an important role in magma propagation and emplacement at shallow levels. Sill propagation and emplacement in heterogeneous and anisotropic crustal segments change the crustal stress field promoting sill arrest, deflection or further propagation. Specifically, sills are more likely to be deflected when encountering shallow dipping layers rather than steeply dipping layers of a fold. Mechanically weak contacts encourage sill deflection due to the related rotation of the stress field and this effect is attenuated when the folded layers are steeper. These processes may change the amount and style of recorded surface deformation, with implications for monitoring of active volcanoes. © 2021 Elsevier B.V.
关键词	Central Andes crustal folds inclined sheets magma emplacement sills
英文关键词	Stresses; Volcanic rocks; Central Andes; Crustal fold; Crustals; Inclined layers; Inclined sheet; Magma emplacement; Property; Rock layers; Sill; Stress field; Volcanoes; crustal structure; emplacement; fold; host rock; magma chamber; sill; stress field; volcanic eruption; Andes
语种	英语
来源期刊	Earth and Planetary Science Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/203058
作者单位	Department of Structural and Geotechnical Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile; Andean Geothermal Centre of Excellence (CEGA), Universidad de Chile, Santiago, Chile; Department of Mining Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile; Royal Holloway University of London, Department of Earth Sciences, Egham, TW20 0EX, United Kingdom
推荐引用方式 GB/T 7714	Clunes M.,Browning J.,Cembrano J.,等. Crustal folds alter local stress fields as demonstrated by magma sheet — Fold interactions in the Central Andes[J],2021,570.
APA	Clunes M.,Browning J.,Cembrano J.,Marquardt C.,&Gudmundsson A..(2021).Crustal folds alter local stress fields as demonstrated by magma sheet — Fold interactions in the Central Andes.Earth and Planetary Science Letters,570.
MLA	Clunes M.,et al."Crustal folds alter local stress fields as demonstrated by magma sheet — Fold interactions in the Central Andes".Earth and Planetary Science Letters 570(2021).