Fig. 6: Variations in mare volcanism throughout time.
From: Surges in volcanic activity on the Moon about two billion years ago
a The estimated thicknesses of basaltic lava flows from the nearside basins, including Oceanus Procellarum, Imbrium, Tranquillitatis, Humorum, Congnitum, Nubium, and Insularum (ref. 12), are shown as minimum (black outline) and maximum (gray outline) values. The error bars for the Chang’e-5 samples represent the uncertainty in the average thickness. The vertical axis is a logarithmic scale. b Eruption rates are calculated based on the volume of mare basalts at a given time and the interval between 2 close eruptions. Original data are from ref. 12. and this study. The error bars are calculated from the uncertainties in lava flow thickness. The inset map shows the terrain slope of the Em4 unit and the position of the Chang’e-5 landing site. The average slope of the Em4 unit is about 3.3°, indicating a relatively flat terrain. Abbreviations: CE5 Chang’e-5, Em4 Eratosthenian-aged mare unit 4, Ga Giga annum.
