A study of lunar typical crater ejecta and its implications for lunar geologic mapping

Crater is the most typical geologic unit on the lunar surface. As the outer part of a crater, the ejecta often occurs even beyond ten crater diameters, which makes it one of the most important features during lunar geologic mapping. By using of the lunar orbiter laser altimeter (LOLA) data, wide-angle camera (WAC) images and narrow-angle camera (NAC) images in Lunar Reconnaissance Orbiter (LRO) mission and Clementine UVVIS multispectral data, we studied the 31km in diameter crater Kepler which locates in the nearside mare region and 30km in diameter crater Necho which locates in the farside land region, both of them belong to Copernican. Copernican crater ejecta can be divided into three faces, which are continuous ejecta deposits (CE), discontinuous ejecta deposits (DE) and crater ray (CR). CE is distributed in a max distance of about 2. 6 radii. DE is distributed in a max distance of almost 11 radii, and CR is distributed in a max distance of about 29 radii. This paper stresses the significance of the combination of multi-source data in recognizing the ejecta deposits.-Multi-source data are used in mapping the ejecta of crater Kepler and crater Necho. The asymmetric distributions of these two craters' ejecta indicate that they were formed in an oblique impact respectively.