A rocky hill on the continuous ejecta of Ziwei crater revealed by the Chang'e‐3 mission. Issue 2 (30th March 2020)

• Record Type: Journal Article
• Authors: Ding, ChunYu; Cai, YuZhen; Xiao, ZhiYong; Su, Yan
• Is Part Of: Earth and planetary physics. Volume 4:Issue 2(2020)
• Page Start: 105
• Page End: 110
• Publication Date: 2020-03-30
• Subjects: lunar penetrating radar -- impact crater -- ejecta deposits -- Chang'e‐3 -- permittivity -- Moon; Geophysics -- Periodicals; Earth sciences -- Periodicals; Planets -- Geology -- Periodicals; 550.5
• DOI: 10.26464/epp2020016
• Languages: English
• ISSNs: 2096-3955

Abstract

Abstract : 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.