Despite the critical role of subduction in plate tectonics, the dynamics of its initiation remains unclear. High-temperature low-pressure metamorphic soles are vestiges of subduction initiation, providing records of the pressure and temperature conditions along the subducting slab surface during subduction initiation that can possibly differentiate the two end-member subduction initiation modes: spontaneous and induced. Here, using numerical models, we show that the slab surface temperature reaches 800–900 °C at ~1 GPa over a wide range of parameter values for spontaneous subduction initiation whereas for induced subduction initiation, such conditions can be reached only if the age of the overriding plate is <5 Ma. These modeling results indicate that spontaneous subduction initiation would be more favorable for creating high-temperature conditions. However, the synthesis of our modeling results and geological observations indicate that the majority of the metamorphic soles likely formed during induced subduction initiation that involved a young overriding plate.

尽管俯冲在板块构造中起着关键作用，但其起始的动力学仍不清楚。高温低压变质底部是俯冲起始的遗迹，记录了俯冲起始过程中沿俯冲板片表面的压力和温度条件，可能区分两种端元俯冲起始模式：自发和诱导。在这里，我们使用数值模型表明，在自发俯冲开始的广泛参数值范围内，板坯表面温度在~1 GPa 时达到 800-900 °C，而对于诱导俯冲开始，只有当年龄达到覆盖板 <5 Ma。这些模拟结果表明，自发俯冲开始更有利于创造高温条件。然而，我们的建模结果和地质观察的综合表明，大多数变质底部很可能是在诱导俯冲开始期间形成的，其中涉及一个年轻的上覆板块。