Boulders on a Hill

Knobby surface of Rutherfurd crater floor: image center 61.340°S, 348.085°E, image width 1050 m, incidence angle 81°, north is top, NAC M1123653329R [NASA/GSFC/Arizona State University].

Today's Featured Image highlights a bumpy hill adjacent to a large melt pool (now frozen to solid rock) inside Rutherfurd crater (48 km in diameter). As seen in the WAC context image below, the floor is mostly littered with materials that collapsed and slumped from the crater wall, and with impact melts filling the topographic lows. 

Uphill is to the left of the image, here you can see a wrinkled/fractured surface, likely formed as a thin rigid sheet of frozen melt. Over time this melt rock slowly broke apart -- the source of other boulders. The boulders slowly migrate downhill, breaking themselves apart, a form of mass wasting similar to that seen on Earth. However there is a big difference, almost all the energy on the Moon is provided by a continual rain of small meteorites, whereas on the Earth erosion is driven by plate motion induced earthquakes, and weathering.

Context view of Rutherfurd crater in LROC WAC monochrome mosaic (100 m/pix), image center is 61.17°S, 347.80°E. The NAC footprint (blue square) and location of the opening image (arrow) are indicated [NASA/GSFC/Arizona State University]. 


Explore the floor of Rutherfurd crater in the full NAC frame with very low sun below!

Related Posts:

Central Peak of Rutherfurd

Rough Crater Wall Surface

Sinuous Cracks

View From The Other Side

Cracked mound

Published by Hiroyuki Sato on 28 January 2014