Geological Chronicle
Rima Hadley is a sinuous lunar rille located on the basaltic plain of Palus Putredinis at the eastern margin of Mare Imbrium. Spanning a total length of 130 kilometers, the channel winds northward along the base of the Montes Apenninus. The rille has an average width of 1.2 kilometers and cuts into the volcanic plain to a maximum depth of 370 meters near the Apollo 15 landing site. Geological analysis indicates the chasm formed during the Imbrian period as an active thermal erosion channel or an underground lava tube whose roof subsequently collapsed.
The channel originates at the elongated volcanic depression Béla, situated among low domes near the Apennine escarpment. As molten basalt erupted from this vent, lava carved a meandering path down the regional slope toward the Imbrium basin. The western and eastern walls slope downward at angles of approximately 25 degrees, revealing distinct horizontal rock outcrops up to 60 meters thick. These exposed bedrock layers preserve individual mare basalt flows that accumulated across successive volcanic episodes.
In July 1971, NASA astronauts David Scott and James Irwin explored the eastern rim of Rima Hadley during the Apollo 15 mission. Driving the first Lunar Roving Vehicle to the edge of the chasm at Station 2 and Station 9, the crew photographed layered basalt strata in the far wall and collected rock samples directly from the rim outcrops. The returned samples and close-up photographs confirmed that sinuous rilles on the Moon are volcanic structures, ruling out earlier theories of water erosion.