Mars Rover Uncovers Compelling Evidence of Ancient Water Activity in "Spiderweb" Rock Formations

NASA's Curiosity rover has made a groundbreaking discovery on Mars, capturing the first close-up images of bizarre, spiderweb-like rock formations. This find offers valuable insights into the Red Planet's ancient, water-rich past.

These intriguing zig-zagging structures, scientifically known as “boxwork,” were identified on the slopes of Mount Sharp, located within Gale Crater, the area Curiosity has been exploring since 2012. These complex, mineral-rich ridges are believed to have been formed by ancient groundwater activity and bear a striking resemblance to webs when viewed from above. Scientists are optimistic that these formations may hold crucial clues about the potential for Mars to have supported microbial life in its distant history.

alt: Curiosity rover discovers spiderweb-like formations on Mars.

Decoding the Martian "Spiderwebs"

Despite their popular nickname, these spiderweb-like formations are not the work of Martian insects. Instead, they are geological features called boxwork. This pattern of intersecting mineral ridges develops when groundwater permeates cracks in the rock, leaving behind mineral deposits. Over time, wind erosion removes the softer surrounding rock, exposing the hardened, web-like framework underneath.

alt: Close-up view of Martian spiderwebs, geological formations created by groundwater.

A Milestone in Martian Exploration

While boxwork formations have been observed from orbit previously, this is the first time they have been examined up close on Mars. Curiosity reached this location in early June 2025, following a months-long journey across Mount Sharp. NASA unveiled the images, along with a 3D interactive video of the formations, on June 23, highlighting them as a high-priority scientific target due to their unique structure and enigmatic location.

alt: Curiosity rover's groundbreaking exploration of boxwork formations on Mars.

Ancient Mars: What the Rocks Reveal

Analysis of the surrounding rocks has revealed veins of calcium sulfate, a salty mineral commonly left behind by groundwater. These findings suggest that the area was once abundant in liquid water, and the subsurface environment may have been warm and salty, potentially creating conditions suitable for microbial life, akin to certain regions on early Earth.

Distinguishing from Other Martian "Spiders"

It's important not to confuse the newly imaged boxwork formations with the so-called "spiders on Mars," which are dark, radial patterns caused by carbon dioxide ice erupting from beneath the surface. Unlike those seasonal features, boxwork is permanent and mineral-based, formed through geological processes rather than atmospheric ones.

Did Mars Once Harbor Life?

Scientists hypothesize that these formations could provide evidence to support the theory that Mars once sustained life. The mineral composition, protected subsurface conditions, and the presence of flowing water all indicate an environment that could have supported microbial organisms. As Kirsten Siebach, a Curiosity mission scientist, noted, "Early Earth microbes could have survived in a similar environment."

Curiosity's Next Steps

Curiosity will continue its investigation of this boxwork area on Mount Sharp, collecting samples through drilling and performing detailed chemical analyses. Researchers are optimistic that these unique structures will not only shed more light on Mars' climate history but also inform future missions searching for signs of life beneath the Martian surface.