Surges in volcanic activity on the Moon about two billion years ago
Heng-Ci Tian, Chi Zhang, Wei Yang, Jun Du, Yi Chen, Zhiyong Xiao, Ross N. Mitchell, Hejiu Hui, H. G. Changela, Tian-Xin Zhang, Xu Tang, Di Zhang, Yangting Lin, Xian‐Hua Li, Fu‐Yuan Wu
Abstract
The history of mare volcanism critically informs the thermal evolution of the Moon. However, young volcanic eruptions are poorly constrained by remote observations and limited samples, hindering an understanding of mare eruption flux over time. The Chang'e-5 mission returned the youngest lunar basalts thus far, offering a window into the Moon's late-stage evolution. Here, we investigate the mineralogy and geochemistry of 42 olivine and pyroxene crystals from the Chang'e-5 basalts. We find that almost all of them are normally zoned, suggesting limited magma recharge or shallow-level assimilation. Most olivine grains record a short timescale of cooling. Thermal modeling used to estimate the thickness and volume of the volcanism sampled by Chang'e-5 reveals enhanced magmatic flux ~2 billion years ago, suggesting that while overall lunar volcanic activity may decrease over time, episodic eruptions at the final stage could exhibit above average eruptive fluxes, thus revising models of lunar thermal evolution.