Having just finished its sampling of the soil at Rocknest, Curiosity is now moving farther north-east into the Glenelg area, and has come across another interesting “curiosity” – small, usually roughly circular ring-like features on some of the surrounding bedrock slabs which look like shallow depressions with a raised rim, kind of like frothy “bubbles” which have popped.
What are they? The fossilized remains of mud bubbles? Tiny impact spots where the rock melted? Just odd weathering? They’ve just been seen in raw images from the last few sols (121-123) so far, but there seem to be a fair number of them. Some of the more prominent ones are posted above and below. In the last two images, what looks like an intact or “unpopped bubble” can be seen just below the ring. Note also the three small holes in it in a triangular pattern. They look like laser holes. Has Curiosity already zapped it?
They are a subject of discussion now on various space forums, etc. Another geological mystery!
All of the Curiosity raw images are here, listed both by instrument and sol.