The oblong crater (34 × 18 kilometers) to the north of the volcano Ceraunius Tholus is a possible source crater for martian meteorites. The crater's elongated shape suggests that it formed by a shallow-angle (grazing) impact, which might have helped eject rocks off the martian surface. These rocks would have orbited the Sun for millions of years before finally landing on Earth.
On the left are a series of graben, similar to those in slide #8. A small impact crater in the upper left has been slightly pulled apart during the formation of one of the graben, and the ejecta blanket of the large crater at left center has been dissected by several graben. Several lava channels flow down the north side of the volcano. One of these channels enters the oblong crater, which has been partially filled by lava. This image is approximately 215 kilometers across.
Viking Orbiter image 516A24