Mare Marginis

Mare Marginis ("sea of the eagle") is a lunar mare that lies on the very edge of the lunar nearside. It differs from most of the nearside maria; it has an irregular outline and it appears to be fairly thin. It has small circular and elongated features in the mare plains that probably mark impact craters buried by less than 1000 to 1700 feet 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. The major crater to the north of Marginis is Al-Biruni, with Ibn Yunus to the southeast and Goddard to the northwest.