{"title":"Subsurface Rock Abundances in Light Plains and Ejecta Flows of the Orientale Basin","authors":"Yizhen Ma, Zhiyong Xiao, Yichen Wang, Wei Cao, Fanglu Luo, Rui Xu","doi":"10.1029/2025JE008938","DOIUrl":null,"url":null,"abstract":"<p>Smooth deposits with reflectances intermediate of basaltic mares and lunar highlands are widespread on the Moon. Termed light plains, they are mainly formed by ballistic ejecta of impact basins, and recent observations suggest that impact craters smaller than basins are also capable of forming light plains. Light plains are an important component of the lunar shallow crust, and their formation is accompanied by transportation and mixing of materials with different provenances. However, the physical properties of materials in light plains are not well constrained, but they are important to the understanding of the evolution of the lunar shallow crust. This study investigates the subsurface properties of light plains formed by the Orientale basin, and the results are compared to those of cogenetic ejecta flows (EF) formed by the Orientale basin and contemporary basaltic mare nearby. Comparison of radar scattering and thermophysical properties of these units reveals that light plains have higher abundances of centimeter- to meter-sized rock fragments. Based on the spatial distribution of fresh impact craters with and without excavated boulders, subsurface meter-sized boulder distributions are highly heterogeneous across the investigated units, with the greatest heterogeneity observed in light plains emplaced in open topography. The observations suggest that compared to the emplacement of ponded light plains and EF formed by Orientale, emplacement of the light plains in open topography was accompanied by more intense ballistic erosion of the underlying target during re-impact of melt-rich ejecta.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 9","pages":""},"PeriodicalIF":4.0000,"publicationDate":"2025-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Geophysical Research: Planets","FirstCategoryId":"89","ListUrlMain":"https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2025JE008938","RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"GEOCHEMISTRY & GEOPHYSICS","Score":null,"Total":0}
引用次数: 0
Abstract
Smooth deposits with reflectances intermediate of basaltic mares and lunar highlands are widespread on the Moon. Termed light plains, they are mainly formed by ballistic ejecta of impact basins, and recent observations suggest that impact craters smaller than basins are also capable of forming light plains. Light plains are an important component of the lunar shallow crust, and their formation is accompanied by transportation and mixing of materials with different provenances. However, the physical properties of materials in light plains are not well constrained, but they are important to the understanding of the evolution of the lunar shallow crust. This study investigates the subsurface properties of light plains formed by the Orientale basin, and the results are compared to those of cogenetic ejecta flows (EF) formed by the Orientale basin and contemporary basaltic mare nearby. Comparison of radar scattering and thermophysical properties of these units reveals that light plains have higher abundances of centimeter- to meter-sized rock fragments. Based on the spatial distribution of fresh impact craters with and without excavated boulders, subsurface meter-sized boulder distributions are highly heterogeneous across the investigated units, with the greatest heterogeneity observed in light plains emplaced in open topography. The observations suggest that compared to the emplacement of ponded light plains and EF formed by Orientale, emplacement of the light plains in open topography was accompanied by more intense ballistic erosion of the underlying target during re-impact of melt-rich ejecta.
期刊介绍：
The Journal of Geophysical Research Planets is dedicated to the publication of new and original research in the broad field of planetary science. Manuscripts concerning planetary geology, geophysics, geochemistry, atmospheres, and dynamics are appropriate for the journal when they increase knowledge about the processes that affect Solar System objects. Manuscripts concerning other planetary systems, exoplanets or Earth are welcome when presented in a comparative planetology perspective. Studies in the field of astrobiology will be considered when they have immediate consequences for the interpretation of planetary data. JGR: Planets does not publish manuscripts that deal with future missions and instrumentation, nor those that are primarily of an engineering interest. Instrument, calibration or data processing papers may be appropriate for the journal, but only when accompanied by scientific analysis and interpretation that increases understanding of the studied object. A manuscript that describes a new method or technique would be acceptable for JGR: Planets if it contained new and relevant scientific results obtained using the method. Review articles are generally not appropriate for JGR: Planets, but they may be considered if they form an integral part of a special issue.
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