Crater Boguslawsky on the moon: Geological structure and an estimate of the degree of rockiness of the floor

• Published in: Solar system research 2015-12, Vol.49 (6), p.367-382
• Main Authors: Ivanov, M. A., Basilevsky, A. T., Abdrakhimov, A. M., Karachevtseva, I. P., Kokhanov, A. A., Head, J. W.
• Format: Article
• Language: English
• Subjects: Astronomy; Astrophysics and Astroparticles; Astrophysics and Cosmology; Basins; Boulders; Craters; Density; Estimates; Frequency distribution; Geological structures; Geology; Moon; Observations and Techniques; Physics; Physics and Astronomy; Planetology; Radar; Radar data; Rock; Rocks; Slopes; Space exploration
• ISSN: 0038-0946; 1608-3423
• DOI: 10.1134/S0038094615060039

The paper considers the results of a study of the geological structure of the floor of the crater Boguslawsky selected as a primary target for the Luna-Glob mission. The deplanate floor of the crater is covered by the material ejected from remote craters and the crater Boguslawsky-D on the eastern inner slope of the crater Boguslawsky. It is highly probable that the sampling of the crater Boguslawsky-D ejecta will provide the unique possibility to detect and analyze the material that predates the formation of the largest and most ancient currently known basin on the Moon—the South Pole–Aitken basin. The rockiness degree of the Boguslawsky crater floor has been estimated from the radar data and the manual boulder counts in the superresolution images (0.5 m/pixel obtained with the Narrow Angle Camera from the Lunar Reconnaissance Orbiter ). Comparison of the radar data to the results of the photo-geological analysis shows that the main contributor to the radar signal is the rock debris located in the subsurface layer sounded by radar (1–1.5 m), while there are practically no boulders on the surface. The two most rocky regions on the crater Boguslawsky floor are associated with the relatively fresh impact craters 300–400 m in diameter. The spatial density of boulders near the craters suggests that one of them is 30–50 Myr older than the other. For both of these craters, the spatial density of boulders drops with the distance from their rims. The rate of the decrease in the boulder spatial density is the same for both craters, which points to the constant-in-time intensity of the fragmentation of boulders. The size distribution of boulders versus the distance from a rim of the older crater is approximated by the curve with a slope of–0.02, while the curve slope for the younger crater is–0.05. The gentler curve slope for the older crater is obviously connected with the equalization of sizes of the rock debris with time. The size-frequency distribution of all rock fragments for the both craters, regardless of the distance from the rim, shows that mainly large boulders first crumble away as the surface age increases. Some large boulders near the young crater demonstrate the traces of rolling, while such traces are absent for the boulders near the older crater. This allows us to estimate the intensity of the reworking of a thin surface layer at 0.01 m/Myr.