On July 17, researchers from the National Space Science Center (NSSC), Chinese Academy of Sciences, announced that they have systematically analyzed plagioclase exposures within the lunar Apollo Basin and successfully identified 51 sites of pure anorthosite (PAN). These sites are distributed across the northern and southern rims, basin floor, and central peak ring of the Apollo Basin. This suggests that the lunar samples returned by Chang'e-6 from the Apollo Basin may contain anorthosite representative of the primordial lunar crust. The findings have been published in the Journal of Geophysical Research: Planets.

Why the lunar near side and far side are so different has long been a mystery. Chang'e-6 collected its samples from the Apollo Basin on the Moon's far side.

In this latest study, the team used multi-band imaging data from the Lunar Reconnaissance Orbiter's Diviner instrument and compared Chang'e-6 sample spectra with known lunar rock databases, simulated spectra, and Apollo-returned anorthosite samples. They successfully located 51 clear exposures of plagioclase-rich rock, confirming these sites contain highly pure plagioclase—true pure anorthosite.

The Chang'e-6 landing site is located in the southern mare plains of the Apollo Basin, surrounded by multiple impact craters containing pure anorthosite exposures. Simulations show that material ejected from these anorthosite-bearing craters has accumulated more than 10cm thick at the Chang'e-6 landing point. This means that when Chang'e-6 scooped lunar regolith, it very likely included fragments from the Moon's most ancient primordial crust. Additionally, the Apollo Basin also hosts possible mantle-derived low-calcium pyroxene. Therefore, the lunar "soil souvenirs" brought back by Chang'e-6 are highly likely to contain material from both the primitive lunar crust and the lunar mantle.