CHINESE MOON MISSION UPENDS THEORIES OF LUNAR VOLCANISM
An analysis of lunar samples returned by China’s Chang’e 5 has produced a new possible answer for volcanism late in the Moon’s history. Samples returned by the Apollo and Luna missions are all older than 3 billion years, but samples returned by Chang’e 5 in late 2020 confirmed that rocks in the area were only 2 billion years old. Scientists speculated that either a relatively high water content or the presence of radioactive heat-producing elements in the lunar interior might have driven volcanism in some areas, but new data appears to have ruled out these hypotheses.
Researchers led by Chen Yi from the Institute of Geology and Geophysics of the Chinese Academy of Sciences found that a lower melting point for portions of the lunar mantle could be due to the presence of fusible easily melted components, leading to young lunar volcanism. Researchers conducted a series of simulations to compare 27 samples of Chang’e 5 basalt clasts with Apollo basalts.
They found that the young magma collected by Chang’e 5 had higher calcium oxide and titanium dioxide contents than older Apollo magmas. These late-stage lunar magma ocean cumulates are more easily melted than early cumulates.