Global Distribution of Large Lunar Craters: Implications for Resurfacing and Impactor Populations

Abstract

By using high-resolution altimetric measurements of the Moon, we produced a catalog of all impact craters ≥20 kilometers in diameter on the lunar surface and analyzed their distribution and population characteristics. The most-densely cratered portion of the highlands reached a state of saturation equilibrium. Large impact events, such as Orientale Basin, locally modified the prebasin crater population to ~2 basin radii from the basin center. Basins such as Imbrium, Orientale, and Nectaris, which are important stratigraphic markers in lunar history, are temporally distinguishable on the basis of crater statistics. The characteristics of pre- and postmare crater populations support the hypothesis that there were two populations of impactors in early solar system history and that the transition occurred near the time of the Orientale Basin event.

Extent, age, and resurfacing history of the northern smooth plains on Mercury from MESSENGER observations

“…For instance, the extensive highreflectance rays emanating from Hokusai crater indicate deposition of excavated crater materials within the NSP. Similar density trends were observed surrounding Orientale basin on the Moon in a study of global crater density by Head et al (2010). In some cases, such as the areas surrounding craters Abedin, Hokusai, Rustaveli, and Oskison, the irregular boundaries between the areas of low and moderate density reflect both the geological effects of ejecta emplacement and smoothing inherent in the density technique.…”

Exogenic Dynamics, Cratering, and Surface Ages

“…The shape of the curve may be distorted by considering large and small crater diameters separately, and this is reflected in the diversity of shapes of the various models. Nevertheless, this fact led to the idea that the projectile population changed over time (Fassett et al, 2012a,b;Head et al, 2010;Strom et al, 2005;Werner, 2008), which violates the traditional postulate that the source region of the projectile population, planetary orbits, and the mass distribution within the solar system have never been reconfigured over its lifetime. Marchi et al (2012a) argued for the significance of velocity effects for craters around 45-60 km diameter on about 4 Ga old lunar surfaces, resulting from the postulated 'Nice event' during the migration of giant planets.…”

“…Because of geologic activity, as well as atmospheric interaction of the projectiles in the cases of Venus and Earth, all curves significantly deviate from the assumed crater-production function. Catalogs used for deriving the crater distributions are from Head et al (2010) for the Moon, modified after Barlow (1988) for Mars; Venus' craters are plotted according to Herrick and Phillips (1994); for Earth, we used the Earth Impact Database (http://www. passc.net/EarthImpactDatabase/index.html) and our own database for Mercury.…”

New observational evidence of global seismic effects of basin‐forming impacts on the Moon from Lunar Reconnaissance Orbiter Lunar Orbiter Laser Altimeter data

“…In this scenario, the formation of each new basin could significantly modify the roughness signature of a preceding basin. Orientale, being the last of the large basins [Wilhelms, 1987;Head et al, 2010], is thus the only well-preserved. What factors associated with the Orientale basin-forming event could account for this degradation process?…”