DOI: 10.1038/ngeo2110
论文题名: Off-rift volcanism in rift zones determined by crustal unloading
作者: Maccaferri F. ; Rivalta E. ; Keir D. ; Acocella V.
刊名: Nature Geoscience
ISSN: 17520894
出版年: 2014
卷: 7, 期: 4 起始页码: 297
结束页码: 300
语种: 英语
Scopus关键词: crust-mantle boundary
; crustal structure
; dike
; magma
; rift zone
; unloading
; volcanism
英文摘要: When continents are stretched over a long period of time, deep elongated rift valleys form at Earthâ €™ s surface and zones of ponded magma, centred beneath the rift, form at the crust-mantle boundary. Ascending magma sometimes erupts within the rift valley or, counterintuitively, at volcanic fields away from the rift valley that are offset by tens of kilometres from the source of magma at depth. The controls on the distribution of this off-rift volcanism are unclear. Here we use a numerical model of magmatic dyke propagation during rifting to investigate why some dykes reach the surface outside the rift valley, whereas others are confined to the valley. We find that the location of magmatism is governed by the competition between tectonic stretching and gravitational unloading pressure, caused by crustal thinning and faulting along the rift borders. When gravitational unloading dominates over tectonic stretching forces, dykes ascending from the ponded magma are steered towards the rift sides, eventually causing off-rift eruptions. Our model also predicts the formation of stacked magma sills in the lower crust above the magma-ponding zone, as well as the along-rift propagation of shallow dykes during rifting events, consistent with observations of magmatism and volcanism in rift zones globally. We conclude that rift topography-induced stress changes provide a fundamental control on the transfer of magma from depth to the surface. © 2014 Macmillan Publishers Limited. All rights reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/106597
Appears in Collections: 气候减缓与适应 科学计划与规划
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作者单位: GFZ German Centre for Geosciences, Section 2.1, Telegrafenberg, 14473 Potsdam, Germany; Institute of Geophysics, University of Hamburg, Bundesstr. 55, 20146, Hamburg, Germany; National Oceanography Centre Southampton, University of Southampton, Southampton, SO14 3ZH, United Kingdom; Dipartimento di Scienze, University of Roma Tre, L. S.L. Murialdo, 1, 00146, Rome, Italy
Recommended Citation:
Maccaferri F.,Rivalta E.,Keir D.,et al. Off-rift volcanism in rift zones determined by crustal unloading[J]. Nature Geoscience,2014-01-01,7(4)