LROC: Debris flows in Gardner crater

Base of an avalanche flow at the contact between the east-southeast wall and floor of Gardner crater (17.73°N, 33.81°E), full 0.49 meter per pixel resolution section from LROC Featured Image released January 17, 2012. LROC Narrow Angle Camera (NAC) observation M121987140R, orbit 3111, February 28, 2010; altitude 43.37km, incidence angle 32.75° [NASA/GSFC/Arizona State University].

Full width of the LROC Featured Image, a field of view approximately 800 meters wide. View the full-size (2000 x 2000) LROC Featured Image HERE [NASA/GSFC/Arizona State University].

James Ashley
LROC News System

Among the most visually spectacular revelations of the Narrow Angle Camera are the variety of landforms showing the many ways that debris flows interact with their landscapes. Like a braided stream, these dry flows of pulverized rock twist and turn their way down the slopes of Gardner crater (17.7°N, 33.8°E) until they come to rest on the crater floor. Gardner is located within the boundary highlands separating Mare Tranquillitatis and Mare Serenitatis. Visible are signs of sheering within the flows as some portions met with enough frictional resistance to cease flowing, while other portions continued down the slope. Imagine this surging wall of fluidized rock plummeting down the crater wall and out onto the floor shortly after the impact excavated the main crater. It would have been a jaw-dropping sight to behold!

LROC Wide Angle Camera (WAC) 60 meter per pixel monochrome (604 nm) mosaic showing the immediate vicinity of Gardner and it's steep walls. The NAC observation focuses on the contact between floor and east-southeastern wall, an almost 2000 meters drop in elevation from the crater rim, and where the local sunrise on May 21, 2010 had just occurred [NASA/GSFC/Arizona State University].

The context image below shows Mare Tranquillitatis basalt deposits visible in the margins surrounding the narrow region of higher terrain where Gardner crater is located. Nearby Maraldi crater (northeast of Gardner) has been filled with similar deposits.

LROC WAC mosaic context image from the LROC QuickMap (125 meter resolution) shows the full 18 km-diameter Gardner crater and Maraldi to the northeast. [NASA/GSFC/Arizona State University].

A few minutes of exploration with the full NAC frame (HERE) will make these flows come alive!
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