Slab dip, surface tectonics: How and when do they change following an acceleration/slow down of the overriding plate?
Slab dip, surface tectonics: How and when do they change following an acceleration/slow down of the overriding plate?
复制标题
板块倾角、地表构造：随着上方板块的加速/减速，它们如何以及何时发生变化？
DOI：
10.1016/j.tecto.2018.01.030
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发表时间：
2018
期刊：
影响因子：
2.9
通讯作者：
N. Cerpa
中科院分区：
文献类型：
--
作者：
Benjamin Guillaume;S. Hertgen;J. Martinod;N. Cerpa
我们提出了模拟模型，模拟海洋岩石圈在以可变速率前进的板块下方俯冲的情况。收敛速度是由该实验集中的横向边界条件决定的。我们分析了板的几何形状和覆盖板的变形。实验证实，一方面是上覆板块的绝对速度，另一方面是俯冲板块的几何形状和上覆板块的变形之间的强相关性。随着运动学边界条件的瞬时变化，俯冲系统逐渐转变为新的稳态状态。模型表明，从先前的平衡转变到新的平衡所需的调整时间与施加的上板速度无关。瞬态阶段持续 ∼ 12.5 ± 6m.y。对于浅板片倾角（100-150 公里深度），∼ 29.2 ± 10m.y。对于更深的板片倾角（300-350 公里深度），以及 ∼ 2.2 ± 2m.y。对于上板变形。对当今俯冲带及其过去 20m.y 演化的分析表明，调整时间约为 15m.y。用于浅板坯倾角和~20m.y。用于大自然中的深板浸入。由于只有少数俯冲带在过去 15 m.y. 中表现出恒定的上板块速度，这表明它们中的大多数目前处于瞬态阶段。
We present analogue models simulating the subduction of an oceanic lithosphere beneath an overriding plate advancing at variable rates. The convergence velocity is imposed by lateral boundary conditions in this experimental set. We analyze the geometry of the slab and the deformation of the overriding plate. Experiments confirm the strong correlation between the absolute velocity of the overriding plate on the one hand, the geometry of the subducting plate and the deformation of the overriding plate on the other hand. Following an instantaneous change in kinematic boundary conditions, the subduction system progressively shifts to a new steady-state regime. Models suggest that the adjustment time necessary to shift from the previous to the new equilibrium is independent of the imposed upper plate velocity. Transient stage lasts ∼ 12.5 ± 6 m.y. for the shallow slab dip (100–150-km depth), ∼ 29.2 ± 10 m.y. for the deeper slab dip (300–350-km depth), and ∼ 2.2 ± 2 m.y. for the upper plate deformation. The analysis of present-day subduction zones and their evolution through the last 20 m.y suggests an adjustment time of ∼15 m.y. for shallow slab dip and ∼20 m.y. for deep slab dip in Nature. Since only few subduction zones have shown a constant upper plate velocity over the last 15 m.y., it suggests that most of them are in a transient stage at present-day.