The Inner Workings of Crustal Distillation Columns; the Physical Mechanisms and Rates Controlling Phase Separation in Silicic Magma Reservoirs
The Inner Workings of Crustal Distillation Columns; the Physical Mechanisms and Rates Controlling Phase Separation in Silicic Magma Reservoirs
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DOI：
10.1093/petrology/egy103
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发表时间：
2019-01-01
影响因子：
3.9
通讯作者：
Huber, Christian
中科院分区：
文献类型：
--
作者：
Bachmann, Olivier;Huber, Christian
奥利维尔·巴赫曼是苏黎世联邦理工学院火山学和岩浆岩石学教授。他在日内瓦大学获得博士学位，并在华盛顿大学（美国）担任博士后研究员和教授，2012年移居苏黎世。Olivier一直喜欢专注于岩浆系统动力学的合作研究，试图合并来自不同领域的数据，包括野外工作，岩石学，地球化学，地质年代学，地球物理学和数值模型。特别是，岩浆库中发生的事情导致超级喷发一直是他研究的主要动力。克里斯蒂安·胡贝尔是布朗大学地球物理学副教授。他在日内瓦大学学习地球科学和物理学，然后在美国加州大学伯克利分校攻读博士学位。在搬到布朗大学之前，克里斯在格鲁吉亚理工学院担任教职。克里斯的作品与多相系统的动力学过程，重点是岩浆系统。火成过程对我们星球的形成有着根本性的影响：它们有助于大陆的生长，控制火山活动，形成矿床，并为我们的大气提供最不稳定的元素。在这种火成分异过程中，相分离起着关键作用，就像在所有蒸馏过程中一样。因此，这种相分离是如何以及以多快的速度发生的，这是为了更好地了解地球（和其他行星）的内部运作而需要解决的关键问题。在这篇观点文章中，我们将回顾一些最重要的方面，管理火成蒸馏的过程，考虑三个不同的阶段（晶体-熔体-流体，粘度和密度递减顺序）在重力场中的机械分离过程的影响。我们还将讨论外部因素（如构造力，岩浆补给，地震波）对相分离的潜在影响。无论地壳分异柱中驱动相分离的能量来源如何，低结晶度的晶体沉降和中高结晶度的压实在从熔体和流体中分离硅酸盐矿物方面发挥了重要作用。我们认为，压实没有任何相关的变形的固体（在此称为晶体repacking '）是一个重要的过程，可以提取高达百分之几十（体积）的熔体从其晶体基质，特别是在浅油藏。通过压实作用提取熔体的速度可能相对较慢，需要数百年至数千年才能产生大的贫晶体口袋（> 10秒至100秒km（3）的熔融熔体）。替代工艺，如气体驱动的压滤或通过剪切或变形的熔体分离，可以根据具体条件增强或抑制相分离，但它们在结晶系统中不太可能特别有效。
Olivier Bachmann is Professor of volcanology and magmatic petrology at the ETH Zurich. He obtained his PhD at the University of Geneva, and held positions of post-doctoral fellow and professor at the University of Washington (USA) before moving to Zurich in 2012. Olivier has always enjoyed collaborative research focusing on the dynamics of magmatic systems, trying to merge data from different realms, including fieldwork, petrology, geochemistry, geochronology, geophysics, and numerical models. In particular, what happens within magma reservoirs leading to super-eruptions has always been a major drive in his research.Christian Huber is an associate professor of geophysics at Brown University. He studied Earth sciences and then physics at the University of Geneva, before pursuing a PhD at UC Berkeley, USA. Before moving to Brown University, Chris held a faculty position at the Georgia Institute of Technology. Chris works on dynamical processes associated with multiphase systems, with an emphasis on magmatic systems. Igneous processes have a fundamental impact on how our planet is shaped: they contribute to the growth of continents, control volcanic activity, form ore deposits and supply most volatile elements to our atmosphere. In the course of this igneous differentiation, phase separation plays a key role, as in all distillation processes. How, and how fast, this phase separation occurs are therefore critical questions to address to better understand the inner workings of the Earth (and other planets). In this Perspectives article, we will review some of the most important aspects of the processes that govern igneous distillation, considering the effect of three distinct phases (crystals-melt-fluid, in decreasing order of viscosity and density) on mechanical separation processes in a gravity field. We will also discuss the potential impacts of external factors (e.g. tectonic forces, magma recharge, seismic waves) on phase separation. Regardless of the source of energy driving phase separation in crustal differentiation columns, crystal settling at low crystallinity and compaction at intermediate to high crystallinity play a major role in separating silicate minerals from melts and fluids. We suggest that compaction without any associated deformation of solids (herein referred to as crystal repacking') is an important process that can extract up to a few tens of per cent (volume) of melt from its crystalline matrix, particularly in shallow silicic reservoirs. Rates of melt extraction by compaction are probably relatively slow, requiring centuries to millennia to generate large crystal-poor pockets (>10s to 100s of km(3) of silicic melt). Alternative processes, such as gas-driven filter pressing or melt segregation by shear or deformation, can enhance or inhibit phase separation, depending on specific conditions, but they are unlikely to be particularly efficient in silicic systems.