Isotopic and compositional constraints on the source of basalt collected from the lunar farside
Xiaochao Che1,2, Tao Long1,2, Alexander Nemchin1,3
1Beijing Sensitive High Resolution Ion Micro Probe Center, Institute of Geology, Chinese Academy of Geological Sciences, Beijing, China.
Abstract:
Volcanism on the Moon has produced surface basalt deposits, which record lunar interior processes. The Chang'e-6 mission retrieved samples from the South Pole-Aitken basin (SPA) on the Moon's far side. We analyzed basalt fragments collected by Chang'e-6 and found that their composition resembles that of low-titanium basalts previously sampled by the Apollo missions. Uranium-lead (U-Pb) dating indicated a basalt age of 2823.0 ± 5.9 million years and a source 238U/204Pb ratio (μ-value) of 480 ± 56. This high μ-value indicates that the source contained materials that formed during the late stages of lunar magma ocean (LMO) crystallization. The results are consistent with the LMO model, but the Chang'e-6 basalt deviates from the trend in Apollo mission samples of younger basalts having higher μ-values. We suggest that this indicates post-LMO modification of the mantle by the SPA impact.
Related Concept Videos
Mass Spectrometry: Isotope Effect
Inductively Coupled Plasma-Mass Spectrometry (ICP-MS): Interferences
Nuclear Fission
Radioactive Decay and Radiometric Dating
Global Climate Change


