Upon the rover’s arrival at Bright Angel, it was so exciting to see all the interesting features in the rocks of this interval! In particular, these rocks contain an abundance of veins and nodules. Veins are linear features containing mineral crystals that often form thin plates or sheets that cut through the rocks and across other veins. Veins are often more resistant to erosion than the rocks they are found in so they stand out in raised relief. Nodules are small, rounded protrusions in the rocks. Nodules are often sites of mineral formation distinct from the surrounding rock.

Veins and nodules form when water flows through a rock, and minerals crystallize from this water in cracks and empty spaces within the rock. Features like this were previously observed by Perseverance during its exploration of the sedimentary rocks of the western fan, particularly during the “Fan Front Campaign” at Hogwallow Flats. However, these features have been sparse in the margin unit. The omnipresence of veins and nodules in the rocks of Bright Angel is truly striking. We hope to get more data on these interesting features over the next few weeks because they may signify intense water-rock interaction at this site!

Written by Hemani Kalucha, Ph.D. student at Caltech