AN UPDATED CRATER DATABASE FOR DIONE AS PARTNER TO A GLOBAL 1:5M GEOLOGICAL MAP

Our team is producing a 1:5M USGS SIM for Saturn’s moon Dione. Since Dione has terrains with a variety of crater densities from very heavy to lightly cratered [e.g., 1], we will include a global crater database down to a diameter (D) of 3 km. This database will be an update of the one produced in [1] with a smaller completion diameter (previously D = 4 km), global coverage (although the completion diameter may be larger in areas with poorer Cassini ISS imaging), and additional crater properties noted. New crater properties included with crater diameter and location are crater degradation/preservation, confidence feature is a crater, if crater appears in a chain or cluster, interior morphology (e.g., central peak/pit, wall terracing), exterior morphology (e.g., presence of ejecta and type, association with tectonic features), and associated geologic unit. We will also include a layer that indicates where the imaging resulted in inadequate crater identification below the indicated diameters. Identification of craters uses standard techniques [e.g., 1], and we use JMARS tools for measurements and tracking crater properties. The final crater database will also be used to define absolute model ages for determined geologic units and build the correlation of map units. Here we present on the progress of the crater database, which is half complete and covers the northern hemisphere. [1] Kirchoff, M.R. & Schenk, P.M. (2015), Icarus 256, 78-89.