Geological Chronicle
Rimae Mersenius is a lunar graben structure spanning 240 kilometers in length across the lunar basalt crust. Formed by structural faulting and crustal extension, the trench cuts through terrain within the Mare Humorum quadrangle (LAC-93).
Officially cataloged by the International Astronomical Union at selenographic coordinates -20.6944° latitude and -46.5288° longitude, the rille designation notes: Named for nearby crater.