Spectral interpretation of late-stage mare basalt mineralogy unveiled by Chang’E-5 samples
Dawei Liu, Xing Wang, Jianjun Liu, Bin Liu, Xin Ren, Chen Yuan, Zhaopeng Chen, Hongbo Zhang, Guangliang Zhang, Qin Zhou, Zhoubin Zhang, Qiang Fu, Chunlai Li
Abstract
The western maria of lunar near-side are widely covered with late-stage mare basalts. Due to the lack of returned samples, the mineralogy of the late-stage basalts was previously speculated as having high abundance of olivine based on remote sensing observation. However, here we show that Chang'E-5 (CE-5) lunar soil samples, the ground truth from past unsampled lunar late-stage mare region, give a different interpretation. Our laboratory spectroscopic and X-ray diffraction (XRD) analyses of the CE-5 soil samples demonstrate that their special spectral signatures are representative of iron-rich high-Ca pyroxene rather than olivine. Considering the spectral and compositional similarities between CE-5 soil samples and lunar late-stage basalts, the mineralogy and petrology of CE-5 samples may be able to be generalized to entire lunar late-stage basalts. Our study would provide a constraint on the thermal evolution of the Moon, especially the young lunar volcanism.