AS16-4502(P)

Figure 119

 Click here for larger NASA image
 Click here for lunar chart showing location

This oblique view of the crater Isidorus D was taken with the panoramic camera on Apollo 16. Isidorus D is about 15 km in diameter and is located in the highlands between Mare Tranquillitatis and Mare Nectaris. Evidence of avalanching (Howard, 1973) and of other types of downslope movement of material are clearly visible on the inner walls of the crater. The streaks resembling shooting stars on the left wall appear to be avalanche scars. The avalanches probably were spearheaded by large blocks followed by fine-grained material. On the near wall (arrow) a larger landslide terminates in a straight line against the relatively flat crater floor. In the shadowed part of the crater wall many short irregular benches or narrow terraces mark the tops of masses of slumped material. The brightness of the avalanche scars is an indication of their freshness; in general, freshly exposed lunar materials are brighter than undisturbed materials nearby.   - F.E.-B.