Insights Into the Causes of Arc Rifting From 2-D Dynamic Models of Subduction
Insights Into the Causes of Arc Rifting From 2-D Dynamic Models of Subduction
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DOI：
10.1002/2017gl075061
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发表时间：
2017-11-16
影响因子：
5.2
通讯作者：
Billen, Magali I.
中科院分区：
文献类型：
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作者：
Billen, Magali I.
弧后扩张中心起源于弧前或弧裂谷事件，当伸展力局部化在岩石圈内时，岩石圈被含水流体或熔融作用削弱。有两种模式被提出来触发弧前/弧裂谷作用：俯冲板块的回滚导致海沟后退或覆盖板块远离俯冲带的运动。本文表明，有第三种机制所造成的原位不稳定时，发生薄的高粘度边界，分离弱弧前热浮力地幔楔，被删除。上涌地幔的浮力导致弧裂作用，推动上覆板块远离俯冲板块，俯冲板块地壳和上覆板块岩石圈有足够的加热，形成埃达克岩或玻安岩火山作用。对于自发的弧前/弧裂谷的发生，必须存在一个广泛的薄弱物质区域，其中一个板块必须能够自由地对上涌力作出反应。
Back-arc spreading centers initiate as fore-arc or arc rifting events when extensional forces localize within lithosphere weakened by hydrous fluids or melting. Two models have been proposed for triggering fore-arc/arc rifting: rollback of the subducting plate causing trench retreat or motion of the overriding plate away from the subduction zone. This paper demonstrates that there is a third mechanism caused by an in situ instability that occurs when the thin high-viscosity boundary, which separates the weak fore arc from the hot buoyant mantle wedge, is removed. Buoyant upwelling mantle causes arc rifting, drives the overriding plate away from the subducting plate, and there is sufficient heating of the subducting plate crust and overriding plate lithosphere to form adakite or boninite volcanism. For spontaneous fore-arc/arc rifting to occur a broad region of weak material must be present and one of the plates must be free to respond to the upwelling forces.