Maria Basalts Chronology of the Chang’E-5 Sampling Site

Chang’E-5 is the first lunar sample return mission of China. The spacecraft was landed in northwest Procellarum KREEP Terrane (43.0576°N, 308.0839°E) on 1 December 2020 and returned 1731 g samples from a previously unvisited region. landing area has been proposed as one youngest mare basalt units Moon holds important information thermal evolution chronology. However, absolute model ages estimated previous studies are quite different, ranging 2.07 Ga to 1.21 Ga. Such significant difference may be caused by (1) different crater counting areas, (2) diameter ranges, (3) effects secondary craters, (4) biases identification. Moreover, accurate site unknown were over Eratosthenian-aged unit (Em4) instead. In light above unsatisfactory conditions, this study seeks establish standard size-frequency distribution CE-5 site. We derived concentrations FeO TiO2 map out pure basaltic areas where external ejecta deposits negligible thus craters rare. Based geochemistry excavated fresh unit, concentration threshold for mapping 17.2 wt.%. morphologically flat subunits selected identification age dating exclude contamination best we could. sampling subunit, detected 313 with greater than 100 m 1.49?0.084+0.084 identified all Em4 gave 1.41?0.028+0.027 As least affected sample-collected subunit can provide constraints cratering chronology function combination isotopic samples.