Thermophysical properties of surface deposits in Tsiolkovskiy crater and its geologic significance revealed by CE-2 MRM data

Abstract

Tsiolkovskiy crater presents one of the few mare deposits on the lunar farside, which are significant to understanding the basaltic magmatism of the Moon. In this paper, for the first time, the thermophysical properties of surface deposits in the Tsiolkovskiy crater were assessed with the brightness temperature (TB), normalized TB (nTB), and TB difference (dTB) maps derived from the Chang'E-2 microwave radiometer data combined with the topography, composition, and rock abundance maps. The main results are presented as follows. (1) The nTB is highly influenced by surface topography, particularly at daytime, as observed in high-frequency maps. However, the influence is limited in the nTB maps at low-frequency channels and dTB maps. (2) We postulate that the substrate temperature in the SW portion of the crater floor might be considerably higher than previously understood. (3) Our observations reveal the presence of mare deposits occurring in two distinct episodes within the mare unit. Notably, the younger mare unit is situated in the NE portion of the crater. (4) The centimeter-scale rocks should be widely distributed in the NE portion beyond the Tsiolkovskiy crater. These findings hold significant implications for advancing our comprehension of the Moon's thermal and basaltic evolutionary processes.