Quantifying Microstructural Evolution in Moving Magma
Quantifying Microstructural Evolution in Moving Magma
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DOI：
10.3389/feart.2020.00287
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发表时间：
2020-09-21
影响因子：
2.9
通讯作者：
Wanelik, Kaz
中科院分区：
文献类型：
--
作者：
Dobson, Katherine J.;Allabar, Anja;Wanelik, Kaz
火山和岩浆研究中的许多重大挑战都集中在了解高度异质系统的动力学以及使岩浆移动或喷发启动的关键条件。从岩浆库的形成和发展，到岩浆的传播和滞留，再到管道条件、气体逃逸、喷发动力学，以及喷发对环境的影响，我们试图定义过程如何发生、它们的速率和时间、以及它们的原因和后果。然而，我们通常无法直接观察这些过程。在这里，我们简要概述了新功能，并强调了现场观测可以提供的潜在见解。我们提出了 XRheo 和 Pele 炉实验装置和分析工具包，用于在流变测试过程中基于原位 X 射线断层扫描对岩浆微观结构演化进行量化。我们展示了第一个 3D 数据，显示了剪切岩浆内不断演变的纹理不均匀性，突出显示了剪切开始时发生的微观结构的动态变化，以及随着变形的进展，微观结构对剪切的响应的变化。这里强调的特定剪切实验重点关注剪切对气泡聚结的影响，以期揭示岩浆传输和破碎过程。 XRheo 系统旨在帮助我们了解岩浆流变学复杂且非牛顿演化的微观结构控制，因此可用于阐明多相岩浆流的流变演化控制的许多动员、传输和喷发现象。因此，这里介绍的样品纹理的详细原位表征代表了流变行为动态微观结构控制的精确参数化新领域的开辟。
Many of the grand challenges in volcanic and magmatic research are focused on understanding the dynamics of highly heterogeneous systems and the critical conditions that enable magmas to move or eruptions to initiate. From the formation and development of magma reservoirs, through propagation and arrest of magma, to the conditions in the conduit, gas escape, eruption dynamics, and beyond into the environmental impacts of that eruption, we are trying to define how processes occur, their rates and timings, and their causes and consequences. However, we are usually unable to observe the processes directly. Here we give a short synopsis of the new capabilities and highlight the potential insights thatin situobservation can provide. We present the XRheo and Pele furnace experimental apparatus and analytical toolkit for thein situX-ray tomography-based quantification of magmatic microstructural evolution during rheological testing. We present the first 3D data showing the evolving textural heterogeneity within a shearing magma, highlighting the dynamic changes to microstructure that occur from the initiation of shear, and the variability of the microstructural response to that shear as deformation progresses. The particular shear experiments highlighted here focus on the effect of shear on bubble coalescence with a view to shedding light on both magma transport and fragmentation processes. The XRheo system is intended to help us understand the microstructural controls on the complex and non-Newtonian evolution of magma rheology, and is therefore used to elucidate the many mobilization, transport, and eruption phenomena controlled by the rheological evolution of a multi-phase magmatic flows. The detailed,in situcharacterization of sample textures presented here therefore represents the opening of a new field for the accurate parameterization of dynamic microstructural control on rheological behavior.