Mars Rover Data Confirms Ancient Lake Sediments on the Red Planet

By Steve Gorman

LOS ANGELES (Reuters) – NASA’s Perseverance rover has confirmed the existence of ancient lake sediments deposited by water that once filled a vast basin on Mars known as Jezero Crater, according to a study released on Friday.

The findings, derived from ground-penetrating radar observations made by the robotic rover, support earlier orbital images and data that led scientists to theorize the presence of water on Mars and the potential for ancient microbial life.

This research, conducted by teams from the University of California at Los Angeles (UCLA) and the University of Oslo, appeared in the journal Science Advances. It was based on subsurface scans captured by the car-sized, six-wheeled rover over several months in 2022 as it traversed from the crater floor onto nearby sedimentary-like features resembling river deltas observed from orbit.

Using the rover’s RIMFAX radar instrument, researchers were able to analyze rock layers up to 65 feet (20 meters) deep, providing a cross-sectional view similar to examining a road cut, explained UCLA planetary scientist David Paige, the study’s lead author.

The data revealed clear evidence that soils transported by water were deposited at Jezero Crater and its delta, akin to sedimentation processes occurring in terrestrial lakes. These findings bolster previous theories that suggest Mars, once cold and arid, was once warmer, wetter, and possibly habitable.

Scientists are eager for an in-depth analysis of the sediments in Jezero, believed to have formed about 3 billion years ago, which are set to be collected by Perseverance for future return to Earth.

The latest study serves as validation that the scientific community selected the right location in their quest to understand Martian geology and biology.

Initial analyses of core samples drilled by Perseverance at four sites near its landing spot in February 2021 had revealed volcanic rocks rather than the expected sedimentary formations. These two studies are not mutually exclusive, as the volcanic rocks showed signs of alteration due to water exposure, prompting scientists to suggest that the original sedimentary deposits might have eroded away.

Recent RIMFAX radar readings also detected signs of erosion before and after the sedimentary layers formed at the western edge of the crater, indicating a complex geological history, according to Paige.

"We landed on volcanic rocks. The significant news is that we’ve now moved onto the delta and observed evidence of lake sediments, which was one of the primary objectives of our mission," Paige stated. "So, that’s a positive development in that regard."