Statistical estimates of rock-free lunar regolith thickness from diviner. (May 2023)

• Record Type: Journal Article
• Authors: Venkatraman, Jaahnavee; Horvath, Tyler; Powell, Tyler M.; Paige, David A.
• Is Part Of: Planetary and space science. Volume 229(2023)
• Publication Date: 2023-05
• Subjects: Moon -- Regolith -- Rock abundance -- LRO Diviner -- Crater statistics; Space sciences -- Periodicals; Atmosphere, Upper -- Periodicals; Sciences spatiales -- Périodiques; Haute atmosphère -- Périodiques; 523
• DOI: 10.1016/j.pss.2023.105662
• Languages: English
• ISSNs: 0032-0633

Abstract

Abstract: The thickness of the lunar regolith has been previously estimated using seismic, radar, and crater morphology data to be on the order of 10 ​m. In this study, we use rock abundance measurements from the Diviner radiometer aboard the Lunar Reconnaissance Orbiter (LRO) to provide new estimates of rock-free regolith thickness in recently-formed impact craters. Diviner cold spots have been shown to last no longer than a few 100 kyr, and thereby point to fresh craters on the Moon. Trends in Diviner data also show that larger, and therefore deeper, cold spot craters have rockier ejecta. We employ statistical analyses to show that cold spot craters in the lunar mare have rockier ejecta at smaller excavation depths when compared to those in the highlands. We estimate that the average rock-free regolith is approximately 10 ​m thick in the mare and 12 ​m thick in the highlands, which is consistent with previous estimates. We expect these values will be highly variable due to differences in regolith development and overturn across the Moon. Highlights: Diviner rock abundance measurements for recent impact craters tell us the depth at which the Moon's regolith becomes rocky. The average Diviner regolith depth estimates are within a few meters of previous estimates. Diviner regolith depth estimates show that the rock-free lunar mare regolith is ∼13% thinner than that in the highlands.