Saturday, April 9, 2011

Bright ridge near Mons Hansteen

Portion of a wrinkle ridge extending from Mons Hansteen to the northeast, cropped LROC News System Featured Image, April 8, 2011; LROC Narrow Angle Camera (NAC) observation M122536322L, LRO orbit 3191, March 3, 2010. Resolution 55 cm per per pixel, Illumination is from the west at an incidence angle of 26° (field of view height is 550 meters) [NASA/GSFC/Arizona State University].

Hiroyuki Sato
LROC News System

On the Moon, small topographic highs often covered by boulders are commonly seen in LROC NAC images. Today's Featured Image shows an example of boulders atop a wrinkle ridge.

In two areas of the image high reflectance boulders are on the top of the ridge. The sinuous line to the right of these boulder clusters is the eastern edge of the wrinkle ridge.

The full-width of the left-hand NAC frame M122536322 shows an archipelago of boulder blossoms, shedding along the ridge, northeast of Mons Hansteen. The centerpiece of of the Featured Image can be seen, with far less detail, in the 2.3 kilometer-wide field of view, and the high solar angle surrenders more reflective (rougher and presumably fresher) material in exchange for a loss in relief [NASA/GSFC/Arizona State University].

Why are there two distinct patches of boulders? The ridge as a whole has numerous boulder patches just like these. How did they form? Were they thrown there by some distant impact event? Are they eroding out of the wrinkle ridge? Has everything nearby been covered by a resurfacing event leaving just a few high patches of bright boulders? We may not know until astronauts visit one of these occurrences and carefully investigate the geology and collect samples!

Context view for the LROC Featured Image, April 8, 2010, northeast of Mons Hansteen in southwestern Oceanus Procellarum. White arrow indicates the location of the shedding wrinkle ridge seen in the Featured image. LROC Wide Angle Camera (WAC) observation M117819862ME, LRO orbit 2496, January 11, 2010 from 43.51 km; centered near 12.34°S, 310.15°E (64.6 meters per pixel) [NASA/GSFC/Arizona State University].

You should check the whole view of this boulder covered wrinkle ridge by opening the full LROC NAC frame!

Related Posts:
Boulder clusters on a ridge crest
Buckland Boulders
Wrinkle ridge in Oceanus Procellarum
Constellation ROI at Mare Tranquillitatis
Hansteen Alpha
Wrinkle Ridges

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