Evidence of volcanism on Mercury: It's the pits
Mon Oct 12, 2009 at 19:17 UTC
Some impact craters on Mercury have non-circular, irregularly shaped depressions or pits on their floors. Such craters have been termed pit-floor craters, and MESSENGER team members have suggested that such pits formed by the collapse of subsurface magma chambers.
If this suggestion is correct, the pits are evidence of volcanic processes at work on the Solar System's innermost planet.
With high-resolution images from MESSENGER’s third Mercury flyby, more pit-floor craters are being identified on Mercury's surface. This NAC image shows a good view of a pit-floor crater imaged last week prior to closest approach.
The large crater near the center of the image contains an elongated bean-shaped depression on its floor and is a pit-floor crater. The slightly smaller crater to the south also contains a pair of depressions on its floor, though from this image alone it cannot be determined if the depressions are pits or overlapping impact craters.
High resolution image
Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
| Source: Johns Hopkins University Applied Physics Laboratory | |
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