Episodic back-arc spreading centre jumps controlled by transform fault to overriding plate strength ratio.
Episodic back-arc spreading centre jumps controlled by transform fault to overriding plate strength ratio.
复制标题
弧后扩张中心的幕式跳跃受转换断层与上覆板块强度比的控制。
DOI：
10.1038/s41467-022-28228-5
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发表时间：
2022-01-31
影响因子：
16.6
通讯作者：
Gueydan F
中科院分区：
文献类型：
--
作者：
Schliffke N;van Hunen J;Allen MB;Magni V;Gueydan F
扩张中心跳跃是大洋弧后盆地的一个共同特征。跳跃通常被认为是由板块速度变化、预先存在的弱点或间断事件（如板块窗口的打开）触发的。在这里，我们提出了弧后扩张中心跳跃的三维数值模型自然地在一个均匀的俯冲系统所包围的大陆没有触发事件。如果海沟到扩张中心的距离太长，扩张中心就会向俯冲带跳跃。特别是，跳跃到一个新的扩展中心时，发生在边界转换断层上的电阻，使弧后和相邻板块的相对运动大于阻力，打破覆盖板块更接近沟槽。扩展中心跳跃的时间和距离，因此，控制转换断层和覆盖板块强度之间的比例。尽管没有自然系统那么复杂，我们的模型解释了为什么狭窄的俯冲板块（例如卡拉布里亚板块）比更宽的俯冲带（例如斯科舍）具有更频繁和更紧密的扩张跳跃。这也解释了为什么弧后盆地在其生命周期中没有扩张中心的跳跃。弧后扩展中心跳跃已经被建议由许多不同的驱动器控制。在这里，作者，使用三维数值模型，表明转换故障可以触发弧后扩展中心跳跃，而不需要任何特设的因素。
Spreading centre jumps are a common feature of oceanic back-arc basins. Jumps are conventionally suggested to be triggered by plate velocity changes, pre-existing weaknesses, or punctuated events such as the opening of slab windows. Here, we present 3D numerical models of back-arc spreading centre jumps evolving naturally in a homogeneous subduction system surrounded by continents without a trigger event. Spreading centres jump towards their subduction zone if the distance from trench to spreading centre becomes too long. In particular, jumps to a new spreading centre occur when the resistance on the boundary transform faults enabling relative motion of back-arc and neighbouring plates is larger than the resistance to break the overriding plate closer to trench. Time and distance of spreading centres jumps are, thus, controlled by the ratio between the transform fault and overriding plate strengths. Despite being less complex than natural systems, our models explain why narrow subducting plates (e.g. Calabrian slab), have more frequent and closely-spaced spreading jumps than wider subduction zones (e.g. Scotia). It also explains why wide back-arc basins undergo no spreading centre jumps in their life cycle. Back-arc spreading centre jumps have been suggested to be controlled by a number of different drivers. Here, the authors, using 3D numerical models, show that transform faults can trigger back-arc spreading centre jumps, without the need of any ad hoc factors.