Crustal Structure and Spectral Features of Lunar Apollo Basin Region

Abstract

The pre-Necterian lunar Apollo impact basin，located inside ancient South Pole-Aitken（SPA）basin，strides the SPA transient cavity and rim. SPA basin is the confirmed largest and oldest basin of the Moon，so the Apollo basin has irreplaceable role in understanding the lunar interior structure and compositions，the local geological processes and the evolutional history of the Moon. The crustal structure of Apollo region is dramatically asymmetric. It's thickening close to SPA rim and thinning close to SPA center，while the thinnest region is inside peak ring of Apollo basin. The absorption features on spectrum are different at different geologic units either. Exterior Apollo basin，the absorption center at locations close to SPA rim tends to be shorter as the Mg pyroxene，while the absorption center at locations close to SPA center tends to be longer as Ca pyroxene. Inside Apollo basin，the spectral features are varying with different spatial locations and geologic units. The maria show absorption feature of Ca pyroxene while the peak ring appears Mg pyroxene rich. The unique characteristics of Apollo basin such as the thinnest crust，the stratigraphic profile as large as 8 km elevation difference，maria erupted from lunar farside，the well-developed peak ring，make it the most valuable sample-return site.

Keywords

Apollo basin / South Pole-Aitken basin / lunar crust / spectrum