AS16-5429 (P)
Figure 91                                                Figure 246

 Click here for larger NASA image of Figure 246
 Click here for larger NASA image of Figure 91
 Click here for lunar chart showing location

This small unnamed crater (right) in Mare Cognitum (C in Figure 91) is unusual because it appears to be deformed by a fault that also bounds a mare ridge. About 5 km in diameter, the crater is obviously older than the mare materials that have buried the outer part of its ejecta blanket. The visible part of the fault extends between the arrows and clearly transects the western wall of the crater. It also marks the west flank of a small mare ridge north of the crater. Viewed stereoscopically, the fault plane can be seen to dip gently to the west, and the surface west of the fault is lower than that on the east. The fault is, therefore, a low-angle normal fault. The abrupt disappearance of the fault at the south rim of the crater may seem surprising. One of several explanations is that it may lie buried beneath a younger basalt flow that flooded the area immediately south of the crater. Many lunar investigators, including several contributors to this volume, have suggested a relationship between faulting and the development of mare ridges. Although this is a very small and certainly uncommon example, it is a convincing example of a mare ridge that is coincident with a fault and thus lends support to this idea.   -G.W.C.

Report Source: NASA SP-362, Page 230, Figure 246

This web page was created by Francis Ridge for The Lunascan Project
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