A rocky hill on the continuous ejecta of Ziwei crater revealed by the Chang’e-3 mission  

作　　者：ChunYu Ding YuZhen Cai ZhiYong Xiao Yan Su 

机构地区：[1]School of Atmospheric Sciences,Sun Yat-sen University,Zhuhai Guangdong 519082,China [2]State Key Laboratory of Lunar and Planetary Sciences,Space Science Institute,Macao University of Science and Technology,Macao 999078,China [3]Chinese Academy of Sciences Center for Excellence in Comparative Planetology,Hefei 230026,China [4]Key Laboratory of Lunar and Deep Space Exploration,National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100012,China

出　　处：《Earth and Planetary Physics》2020年第2期105-110,共6页地球与行星物理（英文版）

基　　金：supported by the National Natural Science Foundation of China (41773063, 41525015 and 41830214);the Science and Technology Development Fund of Macao (0042/2018/A2);the Opening Fund of the Key Laboratory of Lunar and Deep Space Exploration, CAS (no.ldse201702)

摘　　要：The Chinese Chang’e-3 mission landed close to the eastern rim of the ~450 m diameter Ziwei crater. Regional stratigraphy of the landing site and impact excavation model suggest that the bulk continuous ejecta deposits of the Ziwei crater are composed by Erathothenian-aged mare basalts. Along the traverse of the Yutu rover, the western segment features a gentle topographic uplift(~0.5 m high over ~4 m), which is spatially connected with the structurally-uplifted crater rim. Assuming that this broad topographic uplift has physical properties discontinuous with materials below, we use data returned by the high-frequency lunar penetrating radar onboard the Yutu rover to estimate the possible range of relative permittivity for this topographic uplift. Only when the relative permittivity is ~9 is the observed radar reflection consistent with the observed topography, suggesting that the topographic uplift is composed of basaltic blocks that were excavated by the Ziwei crater. This result is consistent both with the impact excavation model that predicts deeper basaltic materials being deposited closer to the crater rim, and with observation of numerous half-buried boulders on the surface of this hill. We note that this study is the first to use topography and radargram data to estimate the relative permittivity of lunar surface uplifts, an approach that has had many successful applications on Mars. Similar approaches can apply other ground penetrating radar data for the Moon, such as will be available from the ongoing Chang’e-4 mission.The Chinese Chang’e-3 mission landed close to the eastern rim of the ～450 m diameter Ziwei crater. Regional stratigraphy of the landing site and impact excavation model suggest that the bulk continuous ejecta deposits of the Ziwei crater are composed by Erathothenian-aged mare basalts. Along the traverse of the Yutu rover, the western segment features a gentle topographic uplift(～0.5 m high over ～4 m), which is spatially connected with the structurally-uplifted crater rim. Assuming that this broad topographic uplift has physical properties discontinuous with materials below, we use data returned by the high-frequency lunar penetrating radar onboard the Yutu rover to estimate the possible range of relative permittivity for this topographic uplift. Only when the relative permittivity is ～9 is the observed radar reflection consistent with the observed topography, suggesting that the topographic uplift is composed of basaltic blocks that were excavated by the Ziwei crater. This result is consistent both with the impact excavation model that predicts deeper basaltic materials being deposited closer to the crater rim, and with observation of numerous half-buried boulders on the surface of this hill. We note that this study is the first to use topography and radargram data to estimate the relative permittivity of lunar surface uplifts, an approach that has had many successful applications on Mars. Similar approaches can apply other ground penetrating radar data for the Moon, such as will be available from the ongoing Chang’e-4 mission.

关 键 词：lunar penetrating radar impact crater ejecta deposits Chang'e-3 PERMITTIVITY MOON 

分 类 号：V476.3[航空宇航科学与技术—飞行器设计] P184[天文地球—天文学]