Young and Old

Unnamed craters on the western edge of Mare Frigoris. LROC NAC M186056576L, image width is 1.65 km, image center is 56.579°N, 334.890°E [NASA/GSFC/Arizona State University].

Today's Featured Image highlights contrasting features of young (lower right) and old (upper left) craters with almost the same diameters (about 450 meters). These two craters are found in the western portion of Mare Frigoris, 23 km south of La Condamine S crater.

The walls of of the younger crater (lower right) are steeper with a small and nearly flat floor, probably from pooled impact melt. On the other hand, the older crater (upper left) appears much shallower and flatter due to an extensive amount of infilling. This type of degraded flat-floored crater is common on the maria. 

Many of the craters in this area appear to have roughly the same amount of infilling. Why? Perhaps a local resurfacing event occurred, meaning that the infill could be either a product of volcanic activity or impact ejecta. If we visit one of these infilled craters and dig a trench or two we could determine whether this infilling material is volcanic or impact ejecta!

Surrounding areas of La Condamine S crater in a LROC WAC monochrome mosaic (100 m/pix). Image width is about 76.6 km, image center is 57.07°N, 335.07°E. The blue box and white arrow indicate the locations of NAC frame and today's Featured Image respectively [NASA/GSFC/Arizona State University].

Explore the contrasting young/old craters and surrounding area in the full NAC frame yourself!

Related posts:
Where Moscoviense meets the Highlands, Wrinkle Ridge Near Montes Teneriffe, Aitken Crater Constellation Program Region of Interest, Montes Pyrenaeus meets Mare Nectaris, Ghost crater in Mare Imbrium

Posted by Hiroyuki Sato on November 13, 2012 11:00 UTC.