On Generation Mechanisms of Excessive Horizontal Compression in Continental Crust

IF 0.9 4区地球科学 Q4 GEOCHEMISTRY & GEOPHYSICS

Izvestiya, Physics of the Solid Earth Pub Date : 2023-06-17 DOI:10.1134/S1069351323030102

Yu. L. Rebetsky

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引用次数: 0

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.

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论大陆地壳过度水平压缩的产生机制

摘要:提出考虑地壳表面剥蚀和岩浆作用过程来解释地壳中水平压应力超过静岩压力升高的形成。如果地壳在深度超过屈服点，岩石挖掘只能通过去除覆盖层的重量来部分地卸载地壳。这是由于在掘出的情况下，卸载是弹性发生的。因此，岩石中产生了在超临界碎裂流阶段获得的残余水平压应力。另一种解释地壳中额外压应力形成的机制涉及火山和岩浆作用。岩浆沿着亚垂直地壳断层和裂缝网络上升，只有当岩浆在传播前沿的压力高于岩石中的水平压缩水平时才有可能。结果表明，在岩浆传播前缘以下，岩石中的水平压应力水平上升到岩浆压力水平。由于地壳下或壳内岩浆房内的压力接近于覆岩的静岩压力，因此断层内岩浆传播前缘上方的断层正交应力超过了垂直压缩水平。因此，地壳岩浆作用能够使地应力状态由水平伸展转变为水平剪切。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Izvestiya, Physics of the Solid Earth 地学-地球化学与地球物理

CiteScore

1.60

自引率

30.00%

发文量

审稿时长

6-12 weeks

期刊介绍： Izvestiya, Physics of the Solid Earth is an international peer reviewed journal that publishes results of original theoretical and experimental research in relevant areas of the physics of the Earth''s interior and applied geophysics. The journal welcomes manuscripts from all countries in the English or Russian language.