Digital and global lithologic mapping of the Moon at a 1:2,500,000 scale

Scientific knowledge of lunar lithologies was first acquired in the 1960s-1970s.The space race between the United States(U.S.)and Soviet Union has promoted numerous manned and robotic lunar exploration missions.Utilizing datasets from these missions,the first series of lunar geologic maps was prepared and published by the U.S.Geological Survey(USGS).The definition of lunar geological features in these maps was mostly based on morphological characteristics but lacked lithological constraints owing to the incompleteness of the compositional datasets avail-able.