Abstract
Von Kármán crater (diameter = ~186 km), lying in the northwestern South Pole-Aitken (SPA) basin, was formed in the pre-Nectarian. The Von Kármán crater floor was subsequently flooded with one or several generations of mare basalts during the Imbrian period. Numerous subsequent impact craters in the surrounding region delivered ejecta to the floor, together forming a rich sample of the SPA basin and farside geologic history. We studied in details the targeted landing region (45.0–46.0°S, 176.4–178.8°E) of the 2018 Chinese lunar mission Chang'E-4, within the Von Kármán crater. The topography of the landing region is generally flat at a baseline of ~60 m. Secondary craters and ejecta materials have covered most of the mare unit and can be traced back to at least four source craters (Finsen, Von Kármán L, Von Kármán L', and Antoniadi) based on preferential spatial orientations and crosscutting relationships. Extensive sinuous ridges and troughs are identified spatially related to Ba Jie crater (diameter = ~4 km). Reflectance spectral variations due to difference in both composition and physical properties are observed among the ejecta from various-sized craters on the mare unit. The composition trends were used together with crater scaling relationships and estimates of regolith thickness to reconstruct the subsurface stratigraphy. The results reveal a complex geological history of the landing region and set the framework for the in situ measurements of the CE-4 mission, which will provide unique insights into the compositions of farside mare basalt, SPA compositional zone including SPA compositional anomaly and Mg-pyroxene annulus, regolith evolution, and the lunar space environment.
| Original language | English |
|---|---|
| Pages (from-to) | 1684-1700 |
| Number of pages | 17 |
| Journal | Journal of Geophysical Research: Planets |
| Volume | 123 |
| Issue number | 7 |
| Early online date | 24 May 2018 |
| DOIs | |
| Publication status | Published - Jul 2018 |
Funding
Reviews by Daniel Moriarty, Aileen Yingst, and an anonymous reviewer were incredibly helpful to help clarify the paper, and much appreciated. We thank the Editor Steven A. Hauck II for comments and editorial help. LRO NAC and WAC data, Chandrayaan-1 M3 data, were downloaded from the PDS (https://pds.nasa.gov/). MI and TC data were downloaded from the SELENE archive (http://darts.isas.jaxa.jp/planet/ pdap/selene/). The data of regolith estimation, subsurface reconstruction and crater count are available in the supporting information. J. H. was supported by National Natural Science Foundation of China (41773061), the Fundamental Research Funds for the Central Universities, MOST Special Fund from the State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences (Wuhan) (CUGL160402, CUG2017G02, and MSFGPMR05). Z. X. was supported by National Natural Science Foundation of China (41773063). The work of J. F. is supported by the CNES (Luna/ExoMars APR). The work of M. M. was supported by a Netherlands Organization for Scientific Research (NWO) grant. The authors also thank Qiong Wang for the discussion of the landing region.
| Funders | Funder number |
|---|---|
| Netherlands Organization for Scientific Research | |
| State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences (Wuhan) | 41773063, CUG2017G02, CUGL160402, MSFGPMR05 |
| National Natural Science Foundation of China | 41773061 |
| Centre National d’Etudes Spatiales | |
| Ministry of Science and Technology of the People's Republic of China | |
| Nederlandse Organisatie voor Wetenschappelijk Onderzoek | |
| Fundamental Research Funds for the Central Universities |
Keywords
- Chang'E-4
- landing site
- South Pole-Aitken basin
- Von Karman