Slides 13–17 show craters of similar size (25–27 km in diameter) in various stages of degradation. The amount of detail seen in the crater rim, interior, and ejecta blanket is a good indication of relative crater age.

14. Slight Degradation

This 25-km-diameter crater is slightly older than the previous crater, as indicated by the more subdued ejecta blanket. This crater probably formed during an episode of fracturing--the crater and ejecta blanket overlie some fractures but are transected by others.

30.69° N, 79.86° W; Viking Orbiter frame 555A32

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