Mare Marginis

Mare Marginis lies on the very edge of the lunar nearside. Thus, it lies halfway between the lunar nearside and farside. It also differs from most of the nearside maria. It has an irregular outline, and it appears to be fairly thin. Note the small circular and elongated features in the mare plains. These probably mark impact craters buried by less than 1000 - 1700 feet (300-500 meters) of lava. Further, Mare Marginis is not centered on any clear, large impact basin. Thus, Mare Marginis seems to mark a low-lying region of the highlands where mare lavas were just able to reach the surface. Several large mare-floored craters also occur nearby. In these craters, the crater floors lie below the surrounding highland surface. Thus, they mark sites around Mare Marginis where lavas were close to the lunar surface. (Lunar Orbiter image IV-165-H3)

Images of Volcanoes To VolcanoWorld