Dark Halo Craters Data

This dataset is a global collection of the longitude and latitude and diameters of dark halo craters. The software used to map the DHCs was Lunar QuickMap.The data for the iron content of the ejecta was found both from the Kaguya (Selene) and Clementine missions. We mapped all longitudes and latitudes of the lunar surface. We determined a crater to be a DHC if it had an ejecta pattern with visibly higher iron content than the surrounding rock. All of the counted DHCs exhibited this quality. We omitted craters that had elevated iron inside the crater rim (as opposed to in the ejecta) because the iron signature inside might result from visible mare that filled in the crater subsequent to impact. Areas associated with visible lunar maria were ignored for this particular data set. We identified and mapped craters globally that had a minimum diameter of 1 km. We mapped the section 40–70 W, 20–70 S with no minimum diameter limit. Determining whether the ejecta had an iron content pattern that is significantly different and distinctive from the surrounding rock is subjective, so we mapped craters conservatively. The surface was mapped by two different people so there could be some additional human error and slight subjectivity of DHCs. We only considered craters with a clearly identifiable ejecta pattern, and we required that the ejecta had to surround at least 25% of the crater. We allowed cases with asymmetrical ejecta. We mapped the craters in 10-degree longitude bands, first checking the iron content and ejecta pattern of craters and then confirmed the DHC with albedo satellite images. We took the longitude and latitude of the center of the crater and measured the diameter with QuickMap tools, from one rim to the other rim.<br>