Two former faces of the moon

Systematic geologic mapping of the lunar near side has resulted in the assignment of relative ages to most visible features. As a derivative of this work, geologic and artistic interpretations have been combined to produce reconstructions of the Moon's appearance at two significant points in its history. The reconstructions, although generalized, show the Moon (1) as it probably appeared about 3.3 billion years ago after most of the mare materials had accumulated, and (2) about 4.0 billion years ago after formation of the youngest of the large multiringed basins, but prior to appreciable flooding by mare material.