Shock-related processes in planetary materials: Earth and beyond

行星材料中与冲击相关的过程：地球及其他地方

• 批准号: RGPIN-2016-05789
• 负责人: Spray, John
• 金额: $ 6.56万
• 依托单位: University of New Brunswick
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=709870
• 关键词: Shock; related; processes; planetary; materials

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.

这项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）使用轻气枪技术的实验室实验;（2）地球撞击结构;（3）来自月球，火星和小行星的外星样品（即，陨石和阿波罗月球样品返回）。冲击波与固体介质的相互作用仍然相对知之甚少，特别是对于多相材料。冲击过程是通过超高速撞击建立我们太阳系的基础;它们仍然是今天许多行星体表面状况的重要贡献者。特别是在微观尺度上，冲击波结构的不均匀性表现为岩石结构和矿物学的改变。拟议的研究将使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6年中，申请人在新玩法大学建立了高速撞击设施。它包括两个轻气枪，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，达到>60 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恢复冲击样本，并使用混响技术来优化冲击持续时间。实验的目的是评估冲击压力增加对长石结构，特别是斜长石的影响，斜长石是许多固体行星体的主要岩石和地壳形成成分。这将是一个重大的进展，在冲击显微结构与冲击压力，建立一个新的冲击规模的斜长石的目标。实验将包括评估maskelynite的形成，以及高压多晶型物的相变和熔融。此外，合成和月球粉末（风化层）将受到冲击，以更好地了解凝聚，熔化和角砾岩形成：许多固体行星体上的重要岩石形成过程。这将建立在过去40年来在北美和欧洲进行的实验工作的基础上。这项研究将拓宽我们对极端条件下材料行为的理解（例如，超高速撞击），这与开发下一代保护系统以造福社会有关（例如，防御轨道碎片和微流星碰撞威胁的空间基础设施装甲）。将使用电子显微镜和拉曼光谱分析冲击产物。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约束良好的样本，将用于地面实况实验工作。这项研究将为本科生和研究生以及我的团队的博士后和研究科学家成员提供出色的，独特的培训机会。