A new global database of Mars impact craters ≥1 km: 2. Global crater properties and regional variations of the simple-to-complex transition diameter

摘要

We have generated a new, 384,343-entry global crater database of Mars, statistically complete for craters with diameters D ≥ 1 km. In this release, the database contains detailed morphologic and morphometric data for craters D ≥ 3 km (future releases will extend these to smaller diameters). With detailed topographic data for the largest crater database to-date, we analyzed crater depth-to-diameter ratios for simple and complex morphologies across various terrains and for the planet as a whole and investigated the simple-to-complex morphology transition. Our results are similar to those in the published literature, but we found a substantial terrain dependence of the simple-to-complex transition that occurs at ～11-km-diameter craters at high latitudes. This suggests a model that requires melting of volatiles during high-latitude crater formation that fill the crater during the modification phase but will still support the simple morphology to larger diameters. We also use this database to reexamine previously observed distributions and patterns to show its fidelity and to further explore other global relationships of fresh craters, those with central peaks, pits, and summit pits. We present the global distribution of craters with different types of ejecta and morphometric properties. Overall, this database is shown to be comparable to previous databases where there is overlap and to be useful in extending prior work into new regimes.