Shock-related processes in planetary materials: Earth and beyond

本研究将通过三种方法探索冲击波与固体材料的相互作用：(1)利用光气枪技术进行实验室实验；(2)陆地冲击构造；(3)来自月球、火星和小行星的地外样本（即陨石和阿波罗月球样本返回）。冲击波与固体介质的相互作用仍然相对知之甚少，特别是多相材料。冲击过程是通过超高速撞击建立太阳系的基础；时至今日，它们仍然是许多行星表面状况的重要贡献者。特别是在微观尺度上，激波结构的非均质性表现为岩石结构和矿物学的改变。拟议的研究将利用天然和合成样品以及实验室实验来探索这些影响。在过去的6年里，申请人在新不伦瑞克大学建立了一个高速冲击设施。它包括两个轻型气枪，可以达到8公里/秒的速度。这使我们能够在受控条件下复制冲击效应到bbb60 GPa（大多数材料的冲击熔化压力）。我们将使用冲击恢复装置来回收冲击样品，并利用混响技术优化冲击持续时间。这些实验将被设计用来评估不断增加的冲击压力对长石结构的影响，尤其是斜长石，它是许多固体行星的主要岩石和地壳形成成分。这将代表在将冲击显微结构与冲击压力相关联方面的重大进展，目标是为斜长石建立一个新的冲击尺度。实验将包括对掩斑岩形成的评估，以及向高压多晶体的相变和融合。此外，合成粉末和月球粉末（风化层）将被震动，以更好地了解团聚、熔化和角砾岩的形成：这是许多固体行星上重要的岩石形成过程。这将以过去40年来在北美和欧洲进行的实验工作为基础。这项研究将扩大我们对极端条件下材料行为的理解（例如，超高速撞击），这与开发造福社会的下一代保护系统有关（例如，用于空间基础设施的装甲，以击败轨道碎片和微尺度碰撞威胁）。用电子显微镜和拉曼光谱分析受冲击的产品。来自月球、火星和小行星的样本，以及来自选定的地球撞击结构的背景良好的样本，将被部署到地面真相实验工作中。这项研究将为我的团队的本科生和研究生以及博士后和科研人员提供优秀的、独特的培养机会。

This research will explore the interaction of shock waves with solid materials via three approaches: (1) laboratory experiments using light gas gun technology; (2) terrestrial impact structures; and (3) extraterrestrial samples from the Moon, Mars and asteroids (i.e., meteorites and Apollo lunar sample returns). The interaction of shock waves with solid media remains relatively poorly understood, especially for polyphase materials. Shock processes have been fundamental in building our Solar System via hypervelocity impact; they remain an important contributor to the surface condition of many planetary bodies today. It is especially at the microscopic scale that heterogeneities in shock wave structure are manifest as modifications to rock texture and mineralogy. The proposed research will explore these effects using natural and synthetic samples and laboratory experiments. In the last 6 years, the applicant has established a high-speed impact facility at the University of New Brunswick. It comprises two light gas guns, which can achieve velocities of 8 km/s. This enables us to replicate shock effects under controlled conditions to >60 GPa (the shock melting pressure for most materials). We will use shock recovery apparatus to retrieve shocked samples, and optimize shock duration by using the reverberation technique. The experiments will be designed to evaluate the effects of increasing shock pressure on feldspar structure, especially plagioclase, which is a major rock- and crust-forming component of many solid planetary bodies. This will represent a major advance in correlating shock microtexture to shock pressure, with the goal of building a new shock scale for plagioclase. Experiments will include an evaluation of maskelynite formation, as well as phase transformations to high pressure polymorphs, and fusion. In addition, synthetic and lunar powders (regolith) will be shocked to better understand agglomeration, melting and breccia formation: an important rock-forming process on many solid planetary bodies. This will build on previous experimental work performed over the last 40 years in North America and Europe. The research will broaden our understanding of materials behaviour under extreme conditions (e.g., hypervelocity impact), which is relevant to developing next-generation protective systems for the benefit of society (e.g., armour for space infrastructure to defeat orbital debris and micrometeroid collision threats). Shocked products will be analyzed using electron microscopy and Raman spectroscopy. Samples from the Moon, Mars and asteroids, as well as contextually well-constrained samples from select terrestrial impact structures, will be deployed to ground-truth experimental work. The research will provide excellent, unique training opportunities for undergraduate and graduate students, and the post-doctoral and research scientist members of my team.