On the physics of crystal-rich mush

发生在火山之下、产生喷发和形成地壳的其他看不见的过程的过程存在很大的不确定性。喷发物质的化学成分和相关的冻结岩体都表明，这些岩浆(熔岩)的自然状态是一种糊状或富含晶体的物质。理解产生火山和化学成分多样性的过程的一个障碍是，对这些蘑菇的物理行为了解很少。这项研究的目的是以新的细节阐明发生在晶体泥中的物理过程如何控制火山和深成系统。这项工作的更广泛影响是，它将增强我们理解、预测和沟通危险以及解释为什么某些过程具有特定时间尺度的能力。它还将把材料科学的新概念引入地质过程的研究，并培训学生广泛应用的新问题解决技能。这项研究工作是由美国和法国五个机构的14名研究人员参与的合作的一部分。研究的目的是通过结合新颖的实验和数值模拟技术来描述和合理化岩浆的行为。这将是第一次使用相同规模的自然材料，以初步协调的方式进行高分辨率的数值和实验室实验。来自实验工作的具体研究产品提供了MUSH描述的运动学元素：局部和系统组构(通过图像分析计算的张量来表示)和整体流变学。数值实验提供了实验室实验中无法获得的信息：力张量和织物。将这两种描述结合起来，产生了一个统一的、可扩展的框架，以揭示对混合行为的控制，而不需要对各种岩浆成分和条件进行特殊假设。实验工作既包括高压装置，格里格斯钻机，也包括更中等压力的帕特森压力机。因此，该项目将探索从莫霍面到近地表的压力范围，具有共同的描述元素。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

There is great uncertainty about the processes that occur under volcanoes, yielding eruptions and other unseen processes that form the Earth's crust. Both the chemical composition of erupted materials and the related 'frozen' bodies of rock, suggests that the natural state of these magmas (molten rock) is a mushy, or crystal-rich material. An obstacle to understanding the processes that produce the diversity in volcanoes and chemical compositions is that there is only a poor understanding of the physical behavior of these mushes. The objective of this research is to illuminate in new detail how the physical processes occurring in crystal mush can control volcanic and plutonic systems. The broader impacts of this work are that it will enhance our ability to understand, anticipate and communicate hazards and to explain why certain processes have particular timescales. It will also bring new concepts from material science into the study of geological processes, and train students in new problem solving skills of wide application.This research effort is one part of a collaboration involving a total fourteen researchers at five institutions, in the USA and France. The research objective is to describe and rationalize the behavior of magma mush by a combination of novel, linked experimental and numerical modeling techniques. This will be the first time that high resolution numerical and laboratory experiments will be employed in an initially coordinated fashion using natural materials at the same scale. The specific research products from the experimental work provide kinematic elements of mush description: local and system fabric (expressed by their tensors calculated by image analysis) and bulk rheology. The numerical experiments provide information unavailable from the lab experiments: force tensors and fabric. Combining these two descriptions yields a unified, extensible framework to reveal the controls on mush behavior without ad hoc assumptions across a wide variety of magmatic compositions and conditions. The experimental work includes both high-pressure apparatus, The Griggs rig, as well as more moderate pressure, the Paterson press. Thus the project will explore a pressure range from the Moho to the near surface with shared elements of description.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.