Pasadena – NASA’s Curiosity rover has captured unprecedented close-up images of unusual rock formations on Mars, dubbed “boxwork,” that suggest the planet once held substantial groundwater reserves for a prolonged period, potentially increasing the likelihood that Mars could have supported microbial life. The discoveries, made within Gale Crater on the slopes of Mount Sharp, reveal intricate networks of ridges and sandy hollows resembling terrestrial boxwork formations, but on a scale far exceeding those found on Earth.
For approximately six months, Curiosity has been exploring this geologically unique region, with the rover’s Mastcam instrument capturing panoramic views on September 26, 2025. These formations, typically only centimeters in size on Earth, rise up to two meters high on Mars, presenting a puzzle for scientists.
“Boxwork so far up on the mountain suggests that the groundwater table was quite high,” explained Tina Seeger, a mission scientist at Rice University, in a statement released by NASA’s Jet Propulsion Laboratory. “And that means that water necessary for life could have been present for much longer than we thought, based on what we’ve seen from orbit.”
The boxwork formations are believed to have originated when groundwater circulated through fractures in the rock, depositing minerals that hardened certain zones. Over billions of years, wind erosion then removed the surrounding, weaker material, leaving behind the more resilient, mineralized ridges. Curiosity’s high-resolution imagery and on-site analyses have provided crucial evidence supporting this hypothesis.
Navigating the terrain proved challenging for the rover team. “It feels almost like a highway where People can drive,” said Ashley Stroupe, an engineer at the Jet Propulsion Laboratory. “But then we have to proceed down into the hollows, where you have to be careful that Curiosity’s wheels don’t slip or obtain stuck in the sand.”
The rover’s investigation confirmed that dark lines visible in satellite imagery correspond to fracture zones where groundwater once flowed. Unexpectedly, Curiosity also discovered nodular structures – termed “Nodules” – located on the sidewalls of the ridges and within the hollows. “We can’t quite explain why the nodules appear where they do,” Seeger stated, indicating a more complex geological history than initially understood.
In addition to imaging, Curiosity conducted analyses of four rock samples using X-ray technology and a high-temperature oven. A particularly promising sample underwent a specialized wet-chemical analysis, a method used to identify organic compounds – the building blocks of life. NASA has not yet released the results of this analysis, but the findings could have significant implications for the search for past life on Mars.
Curiosity will leave the boxwork region in March to continue its exploration of the sulfate-rich layers of Mount Sharp. The rover’s overarching mission remains focused on understanding the evolution of the Martian climate over billions of years and determining how long conditions may have been favorable for the emergence and preservation of life.
