Pressure‐to‐depth conversion is a crucial step toward geodynamic reconstruction. The most commonly used pressure‐to‐depth conversion method assumes that pressure corresponds to the lithostatic pressure. However, deviatoric stresses can cause pressure to deviate from the lithostatic case strongly, thus adding considerable uncertainty to pressure to‐depth conversion. First, we rederive formulas of pressure‐to‐depth conversion that take into account deviatoric stresses. Then, we estimate the range of possible depth independently for each point in a data set containing peak and retrograde metamorphic pressure data (one‐point method). In a second time, we use both the peak and retrograde pressure of a rock sample together, assuming that both pressures were recorded at the same depth (two‐point method). We explore different cases to explain the transition from peak to retrograde pressure by varying the direction and magnitude of stresses. This alternative model is consistent with all data points but for a more restricted range of stress state and depth than the one‐point model. Our results show that (1) even small deviatoric stresses have a significant impact on depth estimates, (2) the second principal stress component σ₂ plays an essential role, (3) several models can explain the pressure evolution of the data but lead to different depth estimates, and (4) strain data offer a mean to falsify our proposed two‐point pressure‐to‐depth conversion. The maximum predicted depth at peak pressure is 170 km using the assumption that pressure is lithostatic, compared to <75 km for our two‐point model, which could correspond to the crustal root Moho's depth.

中文翻译：

---

变质岩压力深度转换模型：推导与应用

压力到深度的转换是进行地球动力学重建的关键步骤。最常用的压力-深度转换方法假定压力与岩石静压力相对应。但是，偏应力会导致压力严重偏离岩石静力学情况，从而给压力至深度转换增加了相当大的不确定性。首先，我们重新考虑了偏应力，重新推导压力到深度的转换公式。然后，我们分别估算包含峰值和逆行变质压力数据的数据集中每个点的可能深度范围（单点方法）。第二次，我们假设岩石压力的峰值压力和逆行压力都记录在同一深度（两点法），我们同时使用它们。我们探讨了不同的情况，通过改变应力的方向和大小来解释从峰值压力到逆行压力的转变。该替代模型与所有数据点都一致，但是应力状态和深度的范围比单点模型更受限制。我们的结果表明，（1）即使很小的偏应力也会对深度估计产生重大影响，（2）第二主应力分量σ ₂起着至关重要的作用，（3）几种模式可以解释数据的压力的变化而导致不同深度的估计，以及（4）应变数据提供了一个平均伪造我们提出的两点压力与深度的转换。假设压力是岩石静压，则在峰值压力下的最大预测深度为170 km，而我们的两点模型则小于75 km，这可能对应于地壳根莫霍面深度。