Curiosity Blog: Approaching Break in Rock Record?

Written by Abigail Fraeman, Deputy Project Scientist, Jet Propulsion Laboratory, California Institute of Technology

Earth planning date: Friday, July 24, 2026

Curiosity spent the week continuing to climb her way up through the layers of Mount Sharp, exploring the sedimentary rock strip chart of Martian history. The rover has reached a layer where the science team had spotted a possible "erosional supersurface" by analyzing orbital data alongside images of the layers in the buttes above us. "Erosional supersurface" is a geologic term that describes places where layers of sediment have been stripped away by wind or water at a regional scale before newer layers are deposited atop them. These surfaces are common in wind-blown sand (aeolian) deposits, and they mark a break in the rock record. After eyeing this unusual section of Mount Sharp for the last few months, it's exciting to finally be so close to this feature. Curiosity's science instruments will give us the geologist's-eye view of this region that we need to really understand this feature, including its composition and centimeter-scale geometry.

Our two plans this week focused on imaging the possible supersurface from a few different locations. This past weekend we backed away from the feature to get a good rover's-eye view of the feature, which set us up nicely on Monday to collect two massive Mastcam mosaics across the entire layer. ChemCam provided additional support by collecting some long-distance RMI images of the most interesting areas of the supersurface. We also took the time to measure the composition of rocks at the bottom of this surface with a MAHLI and APXS target named "Monte Darwin" and ChemCam LIBS targets named "Patacamaya," "Tarucachi," and "Mojoncasa."

Monday's drive took us closer to the supersurface, while taking some MAHLI and Mastcam images of our wheels along the way, and the drive we planned today will bring us right up to the base of the layer. The science team was able to use Monday's image to pick the most scientifically interesting spot to cross this surface, while also juggling constraints made by the reality of where we can drive our rather large rover - there's some pretty sandy and steeply sloping terrain around here, so we also found a spot that looks like it'll be one of the easier areas to traverse. Hopefully next week we'll go up and over the supersurface - stay tuned.