The interface-scale mechanism of reaction-induced fracturing during serpentinization
The interface-scale mechanism of reaction-induced fracturing during serpentinization
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DOI：
10.1130/g33390.1
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发表时间：
2012-12-01
期刊：
影响因子：
5.8
通讯作者：
Jamtveit, Bjorn
中科院分区：
文献类型：
--
作者：
Plumper, Oliver;Royne, Anja;Jamtveit, Bjorn
橄榄岩蛇纹化作用对岩石圈地球化学和岩石物理过程具有一级效应。这一过程引起强烈的压裂，产生流体通道，以促进大量原本不可渗透的岩石的水合作用，但连接界面反应过程与裂缝扩展的机制尚未被理解。通过结合界面耦合溶解-沉淀和裂纹扩展理论的基本方面的橄榄石蜥蜴状蛇纹石化的微观结构特征，我们提出了一个微观结构一致，自蔓延断裂机制。断裂驱动的应力产生的亚稳态非晶原蛇纹石相的生长和转化，其中应力是局部的表面扰动（蚀坑和合并的蚀坑），起源于橄榄石的各向异性溶解。水迁移到裂缝重复的过程，导致分层橄榄石颗粒分割。我们的研究结果表明，在颗粒尺度上的蛇纹石化的进步是独立的固态扩散，不依赖于外力。
Peridotite serpentinization has first-order effects on geochemical and petrophysical processes in the lithosphere. This process induces intensive fracturing, generating fluid pathways to facilitate the hydration of vast amounts of originally impermeable rocks, but the mechanism linking interfacial reaction processes with fracture propagation has not been understood. By combining microstructural characteristics of olivine lizardite-serpentinization with fundamental aspects of interface-coupled dissolution-precipitation and crack growth theory, we propose a microstructurally consistent, self-propagating fracturing mechanism. Fracturing is driven by stress generated from the growth and transformation of a metastable amorphous proto-serpentine phase, where stress is localized within surface perturbations (etch pits and coalesced etch pits) that originate from the anisotropic dissolution of olivine. Water migration into fractures reiterates the process, resulting in hierarchical olivine grain segmentation. Our results indicate that the advancement of serpentinization at the grain scale is independent of solid-state diffusion and does not rely on external forces.