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Abstract <p>Igneous sheet intrusions as discordant dikes or concordant sills make a considerable fraction of the Earth’s crust, and are crucial in the formation and evolution of continental crust. Thus, it is important to understand the dike propagation mechanism that carries magmatic fluids. Crustal segments contain rock layers with contrasting stiffness that can modify dike propagation pathways, leading to their arrest/deflection at mechanical barriers, and produce sills. Employing finite element models by considering a linear-elastic rheology, this study investigates the role of a few key parameters, namely: stiffness and thickness of the intermediate competent layer, dike inclination, and dike overpressure in governing dike propagation pathways. Model results reveal that a stiff layer strongly modifies the stress magnitude and the principal stress trajectories. Magnitudes and lateral extent of tensile stress localization increase considerably as the layer thickness decreases, while it holds an inverse relation with the Young’s modulus, making the layer above the dike vulnerable to multiple fracturing. Results highlight dike inclination as a crucial parameter, controlling fracture propagation. Asymmetric stress distribution developed at the tips of the dikes with inclination ~60º favours dike deflection along the interface as evident from their principal stress trajectories, unlike those associated with higher inclination (i.e., ~80º).</p> Research highlights <p><UnorderedList Mark="Bullet"> <ItemContent> <p>Presence of a stiff rock layer above a propagating dike can modify the stress localization pattern generated in such shallow crustal magma plumbing system.</p> </ItemContent> <ItemContent> <p>Using finite element models, we have evaluated the role of few crucial parameters in dictating the stress localization patterns.</p> </ItemContent> <ItemContent> <p>From the analysis of principal stress directions, this study underscores the conditions that are likely to cause arrest or deflection of the dike along the layer interface.</p> </ItemContent> </UnorderedList></p>

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Stress localization pattern and its role on dike propagation across a stiff rock layer: insights from finite element models

  • 期刊论文

  • 发表日期：

    2026年5月23日

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  • Mukunda Saikia,
  • Pallab Jyoti Hazarika,
  • Amiya Baruah

摘要

Abstract

Igneous sheet intrusions as discordant dikes or concordant sills make a considerable fraction of the Earth’s crust, and are crucial in the formation and evolution of continental crust. Thus, it is important to understand the dike propagation mechanism that carries magmatic fluids. Crustal segments contain rock layers with contrasting stiffness that can modify dike propagation pathways, leading to their arrest/deflection at mechanical barriers, and produce sills. Employing finite element models by considering a linear-elastic rheology, this study investigates the role of a few key parameters, namely: stiffness and thickness of the intermediate competent layer, dike inclination, and dike overpressure in governing dike propagation pathways. Model results reveal that a stiff layer strongly modifies the stress magnitude and the principal stress trajectories. Magnitudes and lateral extent of tensile stress localization increase considerably as the layer thickness decreases, while it holds an inverse relation with the Young’s modulus, making the layer above the dike vulnerable to multiple fracturing. Results highlight dike inclination as a crucial parameter, controlling fracture propagation. Asymmetric stress distribution developed at the tips of the dikes with inclination ~60º favours dike deflection along the interface as evident from their principal stress trajectories, unlike those associated with higher inclination (i.e., ~80º).

Research highlights

Presence of a stiff rock layer above a propagating dike can modify the stress localization pattern generated in such shallow crustal magma plumbing system.

Using finite element models, we have evaluated the role of few crucial parameters in dictating the stress localization patterns.

From the analysis of principal stress directions, this study underscores the conditions that are likely to cause arrest or deflection of the dike along the layer interface.