NASA's Mars Global Surveyor shows a concentrated field of small impact craters. These craters pocked windblown ripples as well as the smooth-surfaced terrain. These are secondary craters.

1 November 2004
The upper right (northeast) quarter of this Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a concentrated field of small impact craters. The features form a broad line running approximately diagonal from northwest toward southeast. These craters pocked windblown ripples as well as the smooth-surfaced terrain. These are secondary craters. That is, they formed second, as the result of a larger impact, probably within a hundred kilometers or so of this site. Secondary craters form from impact of the debris kicked-up by the larger impact event. Instead of rocks from space (like a meteor), these were formed by rocks from a nearby place on Mars. This image is located near 29.7°S, 249.0°W. The picture covers an area about 3 km (1.9 mi) wide. Sunlight illuminates the scene from the upper left.

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