Swarm of Secondaries

Western portion of Crüger crater floor. LROC NAC mosaic (M1108725909R and M1108725909L). Image center is 16.759°S, 292.627°E, image width is 1670 m. Sunlight is from right side. North is up [NASA/GSFC/Arizona State University].

Crüger is a 45 km diameter crater located between Oceanus Procellarum and Orientale basin. The floor is completely covered in basaltic lava deposits, and is very flat. The western portion of the floor shows slightly high reflectance spots with clustered craters and disturbed surfaces, likely a field secondary craters. A unique feature of this grouping is the sharp topographic relief delimiting its southern boundary. The upper half of the opening image, the relatively disturbed and hummocky part, corresponds to the cluster area. Note that the sunlight is from the right side, and the cluster area is topographically lower than the southern relatively smooth area along the delimiting boundary.

NAC context mosaic of M1108725909R and M1108725909L inside Crüger crater floor. Image width is about 7.3 km, image center is 16.736°S, 292.645°E [NASA/GSFC/Arizona State University].

As seen in the NAC context view, the southern end of this secondary cluster is surrounded by this sharp boundary. Likely a densely packed group of ejecta landed with a low angle, resulting in this unique deposition pattern.

WAC monochrome mosaic (100 m/pix) of Crüger crater and surrounding area. Image center is 17.15°S, 293.05°E. Two NAC footprints (blue boxes) and the location of today's Featured Image are indicated here [NASA/GSFC/Arizona State University].

Explore this unique secondary crater cluster patterns in full NAC frame yourself!

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Published by Hiroyuki Sato on 14 May 2013