Planetary Group Seminar: Small craters and the age of planetary surfaces - a tale of wishful thinking (R. Bugiolacci)

The age of cratered planetary bodies’ surfaces across the Solar System are estimated by comparing their crater size-frequency distribution against those in the lunar regions neighbouring the locations of returned (and dated) lunar rocks. For a number of reasons, only craters ≥1 km in diameter were considered statistically relevant. However, in the last few decades we have acquired extensive high-spatial resolution imagery of many planetary surfaces leading to the discovery of significant, but geographically small, new geological formations. This has tempted the planetary community to rely on sub-km, even meters-sized craters to derive Absolute Model Ages (AMA) estimations, many controversial. A new targeted study of a nearly 150,000 small craters (5-100 m in size) questions this approach and the validity of its estimations.