Sunday, May 15, 2011

Discontiguous Rilles

Northwest end of a disconnected depression, possibly a collapsed or buried segment of Rima Marius (14.53°N, 311.43°E), northwest of Marius C and not far east from a similar phenomena investigated by India's Chandrayaan 1 orbiter west of the Marius Hills. LROC Narrow Angle Camera observation M135507533R, LRO orbit 5103, August 3, 2010; solar illumination incidence 58°, field of view 550 meters. View the full-size LROC Featured Image HERE [NASA/GSFC/Arizona State University].

Hiroyuki Sato
LROC News System

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.

Jim Irwin captured this spectacular view of Hadley Rille during the second EVA of Apollo 15 in 1971. See the high-resolution image HERE [NASA/ASJ].

Full-width view of the LROC NAC strip shows the discontinuity in some context [NASA/GSFC/Arizona State University].

LROC Wide Angle Camera (WAC) 100 meter / pixel monochrome mosaic view of Rima Marius, with the discontinuity near its terminus, northwest of Marius C [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 ROI
Marius Hills Pit - Lava Tube Skylight?

A 3.5 kilometer discontiguous rille west of the Marius Hills that may have had origins in common with the sinuous rille system the winds through those hill's largest mounds, now thought to be one volcano. This image was composed from data collected by the Terrain Mapping Camera on-board India's Chandrayaan-1 [ISRO].

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