Degradation of Small Simple and Large Complex Lunar Craters: Not a Simple Scale Dependence

Abstract

The crater record of a planetary surface unit is often analyzed by its cumulative size-frequency distribution (CSFD). Measuring CSFDs involves traditional approaches, such as traditional crater counting (TCC) and buffered crater counting (BCC), as well as geometric corrections, such as nonsparseness correction (NSC) and buffered nonsparseness correction (BNSC). NSC and BNSC consider the effects of geometric crater obliteration on the CSFD. On the Moon, crater obliteration leads to two distinct states in which obtained CSFDs do not match the production CSFD-crater equilibrium and nonsparseness. Crater equilibrium occurs when each new impact erases a preexisting crater of the same size. It is clearly observed on lunar terrains dominated by small simple craters with steep-sloped production CSFDs, such as Imbrian to Eratosthenian-era mare units. Nonsparseness, on the other hand, is caused by the geometric overlap of preexisting craters by a new impact, which is also known as "cookie cutting." Cookie cutting is most clearly observed on lunar terrains dominated by large craters with shallow-sloped production CSFDs, such as the pre-Nectarian lunar highlands. We use the Cratered Terrain Evolution Model (CTEM) to simulate the evolution of a pre-Nectarian surface unit. The model was previously used to simulate the diffusion-induced equilibrium for small craters of the lunar maria. We find that relative to their size, large craters contribute less to the diffusion of the surrounding landscape than small craters. Thus, a simple scale dependence cannot account for the per-crater contribution to degradation by small simple and large complex craters.

Mars Crater Database: A participative project for the classification of the morphological characteristics of large Martian craters

“…It is possible that these small craters were identified by Robbins and Hynek (2012), but that their diameter was underestimated (<1 km in diameter), and the crater was removed from the published database. The low number of new entries identified in our survey is not astonishing since the influence of erosion processes, and more generally all surface processes, on large crater morphologies is limited compared to subkilometric craters, leading thus to a lower degree of subjectivity in the identification of kilometric craters than those smaller craters (Riedel et al, 2020). This result also confirms the completeness of the Robbins and Hynek (2012) database for craters ≥1 km.…”

A young age of formation of Rheasilvia basin on Vesta from floor deformation patterns and crater counts

“…However, another and not less important reason for not including smaller craters for the derivation of AMAs of two main surface units lies in the fact that they are more susceptible to obliteration effects. On bodies lacking atmospheric‐ or plate tectonic‐related erosion, cookie‐cutting (Kneissl et al., 2015; Riedel et al., 2018) or diffusion‐induced equilibrium effects (Richardson et al., 2005; Riedel et al., 2020) can have a significant influence on CSFDS at the small diameter range on relatively ancient geologic units.…”

Studying the Global Spatial Randomness of Impact Craters on Mercury, Venus, and the Moon With Geodesic Neighborhood Relationships

“…H. H. and C. H. vdB were supported by DLR Project 50OW1504. The associated data are available via Mendeley Data: Riedel et al (2020). Studying the global spatial randomness of impact craters on…”

“…The associated data are available via Mendeley Data: Riedel et al. (2020). Studying the global spatial randomness of impact craters on Mercury, Venus, and the Moon with geodesic neighborhood relationships [Data set].…”

“…Richardson, 2009). The intensity to which the individual processes influence the modification of the topography likely depends on the size of the impact (Riedel et al, 2020). Accordingly, the lunar landscape and the visible cratering record is highly influenced by crater formation and erasure.…”