Popis: |
Lunar shallow subsurface structure is important in revealing the formation and evolution of the Moon. Therefore, a review of key issues in the lunar shallow subsurface structure will help deepen our understanding of the Moon. From a global perspective, lunar shallow subsurface structure is formed by endogenic and exogenic geological processes such as volcanic activities, tectonic activities, meteorite impacts, and space weathering. Its morphological characteristics and stratigraphic structure record the evolution of these geological processes. Recent lunar exploration missions have returned new samples and high-resolution data that have greatly enriched our knowledge. On the basis of reviewing the research progress of radar detection, crater-based excavation analysis, material inversion, and heat flow measurement, we also discuss the processes that contribute to the formation of the lunar shallow surface structure, such as volcanoes, impacts, tectonics, and space weathering. The main hot issues were sorted out and focused on 3 areas: transformation of lunar shallow subsurface structure by geological processes, environment and material composition of the lunar shallow surface structure, and physical properties of lunar shallow surface structure. Overall, existing research on the lunar subsurface has made significant progress, but it has also brought more new unsolved mysteries. It is necessary to introduce new applied payloads such as synthetic aperture radar (SAR), orbiter subsurface investigation radar (OSIR), or time-domain electromagnetic sounding (TDEM) to provide higher-resolution subsurface data, and develop better interpretation methodologies, to further deepen the understanding of the lunar shallow subsurface structure and indeed reveal the mechanism of lunar geological evolution. |