Perseverance Finds a Rock With 'Leopard Spots'

NASA's Perseverance Mars rover captured this image of a rock nicknamed "Cheyava Falls" on July 18, 2024, the 1,212th Martian day, or sol, of the mission. Running the length of the rock are large white calcium sulfate veins. Between those veins are bands of material whose reddish color suggests the presence of hematite, one of the minerals that gives Mars its distinctive rusty hue. Scientists are particularly interested in the millimeter-size, irregularly shaped light patches on the central reddish band (from lower left to upper right of the image) that are surrounded by a thin ring of dark material, akin to leopard spots. Spotting of this type on sedimentary terrestrial rocks can occur when chemical reactions involving hematite turn the rock from red to white. Those reactions can also release iron and phosphate, possibly causing the black halos to form, and they can be an energy source for microbes, hence the association between such features and microbes in a terrestrial setting.

Figure A is the same image with annotations pointing out the leopard spots and olivine in the rock.

Measuring 3.2 feet by 2 feet (1 meter by 0.6 meters) and named after a Grand Canyon waterfall, Cheyava Falls was found in an ancient riverbed within the "Bright Angel" region of Mars' Jezero Crater. This image of the rock was captured using a camera called WATSON (Wide Angle Topographic Sensor for Operations and eNgineering), which is part of the SHERLOC (Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals) instrument suite located on the end of Perseverance's 7-foot-long (2-meter-long) robotic arm. SHERLOC looks for organic compounds – carbon-based molecules that are considered the building blocks of life – and detected them in Cheyava Falls.

The white, knobby material seen on either side of the spots is dotted with a few green olivine crystals, which form in igneous rocks such as lava flows. It's unknown whether the olivine formed at the same time as the leopard spots; scientists hope to establish a timeline for when both the olivine and the spots formed.

Perseverance drilled a core from Cheyava Falls, the rover's 22nd rock sample, on July 21.

A key objective for Perseverance's mission on Mars is astrobiology, including the search for signs of ancient microbial life. The rover will characterize the planet's geology and past climate, pave the way for human exploration of the Red Planet, and be the first mission to collect and cache Martian rock and regolith (broken rock and dust).

For more about Perseverance: https://science.nasa.gov/mission/mars-2020-perseverance/