Abstract—It is proposed to consider the processes of surface denudation and magmatism in the Earth’s crust to explain the formation in it of elevated horizontal compressive stresses in excess of lithostatic pressure. Rock exhumation only partially unloads the crust due by removing the weight of the overburden if the crust at depth was above the yield point. This is due to the fact that in the case of exhumation, the unloading occurs elastically. As a result, residual horizontal compressive stresses acquired at the stage of supercritical cataclastic flow arise in the rock. Another mechanism to account for the formation of additional compressive stresses in the crust involves volcanic and magmatic processes. Magma ascent along subvertical crustal faults and networks of fractures is only possible if magma pressure at the propagation front is above the level of horizontal compression in the rock. The result is that below the magma propagation front, the level of horizontal compressive stresses in the rocks rises to the level of magma pressure. Because the pressure in the subcrustal or intracrustal magma chamber is close to the lithostatic pressure of the overburden, fault-orthogonal stresses above the magma propagation front in the fault exceed the level of vertical compression. Thus, crustal magmatization is capable of changing the crustal stress state from horizontal extension to horizontal shear.

摘要—建议考虑地壳中的表面剥蚀和岩浆作用过程，以解释地壳中超过岩石静压力的升高的水平压应力的形成。如果地壳深度高于屈服点，则岩石折返仅通过去除覆盖层的重量来部分卸载地壳。这是因为在折返的情况下，卸载是弹性发生的。结果，在超临界碎裂流阶段获得的残余水平压应力出现在岩石中。解释地壳中额外压应力形成的另一种机制涉及火山和岩浆过程。只有当传播前沿的岩浆压力高于岩石中的水平压缩水平时，岩浆才能沿着近垂直地壳断层和裂缝网络上升。结果是，在岩浆传播前沿下方，岩石中的水平压应力水平上升到岩浆压力水平。由于壳下或壳内岩浆房的压力接近上覆岩层的静岩压力，断层中岩浆传播前沿上方的断层正交应力超过了垂直压缩水平。因此，地壳岩浆作用能够将地壳应力状态从水平拉伸转变为水平剪切。岩石中的水平压应力水平上升到岩浆压力水平。由于壳下或壳内岩浆房的压力接近上覆岩层的静岩压力，断层中岩浆传播前沿上方的断层正交应力超过了垂直压缩水平。因此，地壳岩浆作用能够将地壳应力状态从水平拉伸转变为水平剪切。岩石中的水平压应力水平上升到岩浆压力水平。由于壳下或壳内岩浆房的压力接近上覆岩层的静岩压力，断层中岩浆传播前沿上方的断层正交应力超过了垂直压缩水平。因此，地壳岩浆作用能够将地壳应力状态从水平拉伸转变为水平剪切。