Magnetic Signature of Basalts in the Chang’e-5 Sample Region:
Implications for the Lunar Dynamo
In December 2020, Chang’e-5 returned samples from mare basalt unit
Em4/P58 in northern Oceanus Procellarum. With an absolute model age of
1.21-1.53 Ga (Hiesinger et al. 2003; Qian et al., 2018, 2021a).
Elevation analysis of the interior of Rima Sharp and Mairan, plus
geomorphological observations suggest lava backfilling of Rima Sharp
with younger lava from Rima Mairan. Analysis of the magnetic field at
the surface also shows that the younger lava from the southern Mairan
vents, which covered the southeastern part of Em4/P58 is unmagnetized.
Our new magnetic anomaly analysis shows that Em4/P58 unit can be divided
into magnetized (northwest) and unmagnetized (southeast) parts. The
comprehensive analysis of magnetic anomaly and topography shows that
lava from southern rille is likely to have reached the Chang’e-5 landing
site. Samples returned by Chang’e-5 will help constrain the source of
lava flow and the evolution of the lunar magnetic field over time.