Abundance and size-frequency distributions of boulders in Linne crater's ejecta (Moon)

TL;DR

This study analyzes the abundance and size distribution of boulders around Linne crater on the Moon using high-resolution imagery, revealing insights into ejecta patterns, impact dynamics, and regolith thickness.

Contribution

It provides the first detailed size-frequency distribution and spatial analysis of boulders around Linne crater, including implications for impact mechanics and lunar surface properties.

Findings

Boulder sizes follow a power-law distribution with index -4.03.

Largest boulders are within 2 km of the crater center.

Estimated regolith thickness is approximately 4.75 meters.

Abstract

This paper presents the abundances and the size-frequency distributions (SFD) of the ejected boulders surrounding the Linne crater, located on the Moon's Mare Serenitatis basin. By means of Lunar Reconnaissance Orbiter Camera high-resolution images we prepare a context geological map of the Linne crater as well as we identify 12000 boulders > 4.4 m, with a maximum measured size of 30.8 m. The cumulative number of boulders per km2 is fitted with a power-law curve with index -4.03 +0.09/-0.10. By studying the radial ejecta abundances, we find that the largest ones are located within the first 2 km from the crater's centre, while few tens of boulders with sizes < 8 m are detectable above 5 km from the crater's rim. We find that the Linne proximal ejecta blanket is slightly asymmetrical, as indicated in the geological map too, showing a density increase in the NE-SW direction. This may be the result of an oblique impact emplacement of the original impactor, or it may be explained with a perpendicular impact in the Mare Serenitatis location, but on a surface with lunar basalts with different local mechanical properties. By exploiting our boulders size density as a function of the distance from the crater's centre, we derive a possible regolith thickness at the Linne impact of 4.75 m, supporting similar values based on Earth-based radar and optical data in the Mare Serenitatis basin.