Abstract The surface morphology and roughness of a lava flow provides insight on its lava properties and emplacement processes. This is essential information for understanding the eruption history of lava fields, and magmatic processes beneath the surface of Earth and other planetary bodies such as the Moon. The surface morphology is influenced by lava properties such as viscosity, temperature, composition, and rate of shear. In this work, we seek to understand how we can interpret the emplacement processes and lava properties of lava flows using remote sensing data. Craters of the Moon (COTM) National Monument and Preserve in Idaho hosts a suite of compositionally diverse lava flows with a wide range of surface roughness making it the ideal case study. Lava flows there have surface morphologies consistent with smooth pāhoehoe, slabby pāhoehoe, hummocky pāhoehoe, rubbly pāhoehoe, ‘a’ā, block-`a’ā, and blocky textures. The variation in surface roughness across the lava field reflects changes in lava properties and/or emplacement processes over space and time. We investigate geochemical and petrographic variations of the different lava flow morphologies and analyse how they relate to airborne radar data. Results show L-Band (24 ​cm) radar circular polarization ratios (CPR) distinguish the contrasting surface roughness at COTM, separating the smoother (primitive; low SiO2 and alkali) and rougher (evolved; high SiO2 and alkali) lava flows. However, ambiguities are present when comparing the CPR values for rubbly pāhoehoe and block-`a’ā flow. Even though their CPR values appear similar at the decimetre scale, they have distinct morphologies that formed under different emplacement processes. Without ground-truth information, the rubbly pāhoehoe and block-`a’ā lava flows could therefore be misinterpreted to be the same type of flow morphology, which would lead to false interpretations about their lava properties and emplacement processes. This is important when comparing these flows to lava flows on other planetary bodies that share similar CPR values, such as the Moon. Thus, using terrestrial analogues such as those at COTM can provide an improved understanding of the surface morphology and emplacement processes of lunar lava flows. This will lead to more refined interpretations about past volcanic processes on the Moon.

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从雷达遥感数据解释熔岩流特性

摘要 熔岩流的表面形态和粗糙度提供了对其熔岩性质和侵位过程的深入了解。这是了解熔岩场喷发历史以及地球表面和其他行星体（如月球）下的岩浆过程的重要信息。表面形态受熔岩特性的影响，例如粘度、温度、成分和剪切速率。在这项工作中，我们试图了解如何使用遥感数据解释熔岩流的侵位过程和熔岩特性。爱达荷州的月球陨石坑 (COTM) 国家纪念碑和保护区拥有一系列成分多样的熔岩流，表面粗糙度范围很广，使其成为理想的案例研究。那里的熔岩流具有与光滑 pāhoehoe、slabby pāhoehoe 一致的表面形态，hummocky pāhoehoe, rubbly pāhoehoe, 'a'ā, block-`a'ā, 和块状纹理。整个熔岩场表面粗糙度的变化反映了熔岩性质和/或侵位过程随空间和时间的变化。我们调查了不同熔岩流形态的地球化学和岩石学变化，并分析了它们与机载雷达数据的关系。结果显示，L 波段（24 厘米）雷达圆极化比 (CPR) 区分了 COTM 处的对比表面粗糙度，将更平滑（原始；低 SiO2 和碱）和更粗糙（演化；高 SiO2 和碱）熔岩流分开。然而，当比较碎石 pāhoehoe 和 block-`a'ā 流的 CPR 值时，存在歧义。尽管它们的 CPR 值在分米尺度上看起来相似，但它们具有在不同就位过程中形成的不同形态。如果没有地面实况信息，碎屑 pāhoehoe 和块状-`a'ā 熔岩流可能因此被误解为相同类型的流动形态，这将导致对其熔岩性质和侵位过程的错误解释。当将这些流与其他具有相似 CPR 值的行星体（例如月球）上的熔岩流进行比较时，这一点很重要。因此，使用地球上的类似物，例如 COTM 上的类似物，可以更好地了解月球熔岩流的表面形态和就位过程。这将导致对月球过去火山过程的更精确解释。这将导致对其熔岩特性和侵位过程的错误解释。当将这些流与其他具有相似 CPR 值的行星体（例如月球）上的熔岩流进行比较时，这一点很重要。因此，使用地球上的类似物，例如 COTM 上的类似物，可以更好地了解月球熔岩流的表面形态和就位过程。这将导致对月球过去火山过程的更精确解释。这将导致对其熔岩特性和侵位过程的错误解释。当将这些流与其他具有相似 CPR 值的行星体（例如月球）上的熔岩流进行比较时，这一点很重要。因此，使用地球上的类似物，例如 COTM 上的类似物，可以更好地了解月球熔岩流的表面形态和就位过程。这将导致对月球上过去的火山过程进行更精细的解释。