The bombardment history on the lunar farside revealed by 40 Ar/ 39 Ar geochronology of Chang’e-6 impact melt rocks
- Wan-Feng Zhang
- Le Zhang
- Mang Lin
- Fred Jourdan
- Jun-Jie Wang
- Yan-Qiang Zhang
- Jing-You Chen
- De-Wen Zheng
- Peng-Li He
- Fei Su
- Huai-Yu He
- Hua-Ning Qiu
- Xiu-Juan Bai
- Xiao-Ping Xia
- Ming Xiao
- Ying-De Jiang
- Jun-Jie Li
- Jia Zhang
- Lie Kun Yang
- Fang-Fang Huang
- Bo Wei
- Jiang-Ze Wang
- Qin Zhou
- Yong-Hua Cao
- Ze-Xian Cui
- Qing Yang
- Lin-Li Chen
- Yi-Gang Xu
2026-07-23
The reconstruction of the lunar bombardment history is pivotal to understanding the evolution of Earth-Moon system. So far, it heavily depends on geochronological studies of lunar nearside samples but lacks direct sample constraints from the lunar farside. Here, we present 28 single-clast 40 Ar/ 39 Ar ages of impact melt rocks returned by the Chang’e-6 mission. They reveal impact events spanning from ∼4.33 to ∼1.13 billion years (Ga). In particular, three melt clasts date to ∼4.16 Ga, consistent with the recent dating of the Apollo basin, and only two ages fall at 4.0 to 3.7 Ga. The presence of older ages (>4.0 Ga) and lack of predominant age around ∼3.9 Ga suggest that the lunar farside bombardment was not dominated by a cataclysmic spike but by a smooth long-term decline punctuated by later impacts.