Geologic map of the northern Crisium region

Apollo 17 metric photographs provide the best available coverage for geologic interpretation of northern Mare Crisium and the northern Crisium basin. One region in particular, between Alhazen Crater and longitude 66 E, had previously been covered very poorly. The Apollo 17 photographs provide excellent monoscopic as well as stereoscopic viewing because of the favorably low sun illuminations (15 deg to 49 deg). These new photographic data allow the geology of the basin, the mare, and other nearby terrains to be reevaluated. This reexamination, together with data from continuing moon-wide photogeologic studies and analyses of returned rocks from Apollo landing sites, has produced a simple evolutionary picture of the region, expressed by fewer map units and explained by fewer basic processes than previously thought necessary.