Discontinuous rilles

Northwestern edge of disconnected depression (14.53°N, 311.43°E) from Rima Marius. Image number M135507533R, incidence angle 58°, image width is 550 meters [NASA/GSFC/Arizona State University].

Sinuous rilles (like Hadley Rille, near the Apollo 15 landing site) are narrow, long depressions that meander across the lunar surface like a terrestrial river. Lunar geologists think that sinuous rilles formed either as erupting lavas carved their way through the surface, or by roof-collapse of lava tubes. A portion of the rille (named Rima Marius) in today's Featured Image  is discontinuous, with a partially-closed depression that possibly marks the source region for this rille. Perhaps the "blockage" in the channel is a intact lava tube roof. While there are no signs of any natural bridge structures or other openings in this region, it is possible that a small section of the lava tube might have simply had its entrance and exit blocked by collapse debris.

LROC WAC 100 m/pixel monochrome mosaic. Blue box and white arrow indicate the locations of full NAC frame and today's Featured Image [NASA/GSFC/Arizona State University].

Sinuous rilles like Rima Marius are high priority targets for future human lunar exploration in part because they expose deeply buried mare units, meaning that human exploration of locations like Rima Marius will provide important new scientific insights into the duration and evolution of lunar volcanism.

Explore the entire NAC frame!

Related images:

Sinuous Chain of Depressions, Rilles as far as the eye can see in Prinz!, Rimae Posidonius, Rimae Prinz Region - Constellation Region of Interest, Marius Hills Pit - Lava Tube Skylight?

Published by Hiroyuki Sato on 12 May 2011