The morphology of craters on Mercury: Results from MESSENGER flybys

New morphometric measurements of craters and basins on Mercury and the Moon from MESSENGER and LRO altimetry and image data: An observational framework for evaluating models of peak-ring basin formation

“…The depths of craters and basins on Mercury are generally at the lower depth range of the trend with uncertainties derived from shadow measurements of craters in Mariner 10 images by Pike (1988). Our generally smaller depths calculated from MLA measurements are consistent with similar measurements made by other workers for smaller craters (Barnouin et al, 2012;Talpe et al, 2012), and are likely to reflect differences with Pike (1988) in methodologies and the datasets used for calculations. On Mercury, we also observe a general decrease in the depth-to-diameter ratio (d/D r ) with rim-crest diameter (Fig.…”

Polygonal impact craters on mercury

“…The transition between simple and complex craters on Mercury occurs at a diameter of about 7 km according to Croft (1985) and Schenk and Sharpton (1992). Pike et al (1988) calculated a diameter of about 10 km, and the current value of the transition diameter is given by Barnouin et al (2010) at 12 km. The list of craters on Mercury does not show craters smaller than 12 km (except a tiny one).…”

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

“…The thickness of the NSP was estimated from relations between crater depth and diameter determined by Pike (1988) (Table 1) and recently confirmed with MESSENGER flyby data (Barnouin et al, 2012) in a manner similar to the method used by Head et al (2011). We measured the diameters of buried craters from visible remnants of the crater rim, if evident, and from arcuate wrinkle ridges assumed to overlie the original crater rim where no remnant of the rim survives.…”

“…Mathematical relationships between crater diameter and rim height were developed for craters on Mercury only for diameters between 2.4 km and 43 km because of limited coverage of larger, partially shadowed craters (Pike, 1988). Although recent work on the relation between crater depth and diameter (from 1.3 km to $130 km in diameter; Barnouin et al, 2012) shows that earlier relationship to be valid, the Pike (1988) equations may overestimate crater rim height because the ratio of diameter to depth tends to decrease for larger craters (D > 30 km), particularly at the transitions between crater morphological types (e.g., immature complex to mature complex craters; e.g., Williams and Zuber, 1998;Baker et al, 2011;Barnouin et al, 2012). Moreover, because the crater preservation state at the time of embayment is unknown, these equations likely overestimate the rim heights of degraded craters, which tend to be lower than those of pristine craters.…”