Gediz Vallis Ridge, believed to be a remnant of ancient and powerful debris flows, has long been the focus of the rover’s scientific team. Around three billion years ago, during one of Mars’ last wet periods, immense debris flows carried mud and boulders down the slopes of a massive mountain. These debris flows spread out into a fan-shaped ridge, which was later sculpted by wind, preserving a captivating record of Mars’ watery history.
The Curiosity Mars rover, after three previous attempts, finally reached this ridge, capturing its formation in a 360-degree panoramic mosaic. Previous endeavors were thwarted by sharp “gator-back” rocks and steep inclines. Following one of the most challenging climbs of the mission, Curiosity arrived at this location on August 14, where it could examine the sought-after ridge using its 7-foot (2-meter) robotic arm.
“After three years, we finally found a spot where Mars allowed Curiosity to safely access the steep ridge,” stated Ashwin Vasavada, Curiosity’s project scientist at NASA’s Jet Propulsion Laboratory in Southern California. “It’s a thrill to be able to reach out and touch rocks that were transported from places high up on Mount Sharp that we’ll never be able to visit with Curiosity.”
Curiosity has been ascending the lower part of the 3-mile-tall (5-kilometer-tall) Mount Sharp since 2014, uncovering evidence of ancient lakes and streams along the way. Each layer of the mountain represents a distinct era in Martian history, providing valuable insights into how the landscape evolved over time. Gediz Vallis Ridge is among the most recent features on the mountain, making it one of the youngest geological time capsules Curiosity has encountered.
During its 11-day stay at the ridge, the rover diligently collected images and studied the composition of dark rocks that clearly originated from higher regions on the mountain. These rocks were carried down by the debris flows that contributed to the formation of Gediz Vallis Ridge, providing a rare opportunity to examine material from the upper reaches of Mount Sharp.
Additionally, the rover’s arrival at the ridge granted scientists a close-up view of the eroded remnants of a geological feature known as a debris flow fan. These fans, where debris spreads out into a fan shape as it flows downhill, are common on both Mars and Earth, but scientists are still working to understand their formation.
Geologist William Dietrich, a member of the mission team at the University of California, Berkeley, expressed his fascination, saying, “I can’t imagine what it would have been like to witness these events. Huge rocks were ripped out of the mountain high above, rushed downhill, and spread out into a fan below. The results of this campaign will push us to better explain such events not just on Mars but even on Earth, where they are a natural hazard.”
On August 19, the rover’s Mastcam captured 136 images of Gediz Vallis Ridge, providing a comprehensive 360-degree view of the surrounding area when pieced together into a mosaic. This panorama also includes the path Curiosity took up the mountainside, passing through “Marker Band Valley,” where evidence of an ancient lake was uncovered.
While scientists continue to analyze the imagery and data from Gediz Vallis Ridge, Curiosity has already shifted its focus to its next challenge: finding a path to the channel above the ridge to further investigate how and where water once flowed down Mount Sharp.
Curiosity was constructed by JPL, managed by the California Institute of Technology (Caltech) in Pasadena, California. JPL leads the mission on behalf of NASA’s Science Mission Directorate in Washington.