Earth Science Frontiers ›› 2025, Vol. 32 ›› Issue (6): 276-285.DOI: 10.13745/j.esf.sf.2025.8.64

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Seismic shock induced formation of garnet coronas in eclogites: A perspective

YANG Jianjun()   

  1. State Key Laboratory of Lithospheric and Environmental Coevolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
  • Received:2025-04-06 Revised:2025-07-02 Online:2025-11-25 Published:2025-11-12

Abstract:

High-pressure metamorphic rocks are distributed along fossil seismic faults in orogenic belts. It is generally believed that high-pressure metamorphism occurs due to fluid infiltration into deep faults within subducted slabs. However, studies of garnet coronas in eclogites show that these textures are characteristic of mineral growth through fluid-absent metamorphic reactions, reflecting disequilibrium during the formation of the eclogite assemblages. Phase diagram modeling of plagioclase pseudomorphs from various localities indicates that the high-pressure assemblages are H2O-undersaturated. On the other hand, the corona textures, like the stellate and micropoikilitic textures, suggest crystallization in rapid processes. The rapid growth of high-pressure minerals under H2O-undersaturated conditions requires unusually high diffusion and reaction rates, which can be explained by the effect of seismic shock waves. This is supported by accumulating evidence, here particularly referenced to data at Yangkou in the Chinese Su-Lu high-pressure metamorphic belt.

Key words: corona, disequilibrium, eclogitization, reaction rate, seismic shock, solid-state diffusion

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