NASA’s Mars rover Curiosity only has so much time to complete its mission, so when scientists running the project decide to make a U-turn – it must be for something important.

The NASA team turned around their rover to investigate a large rock formation, dubbed Elk, found to have surprisingly high levels of silica. High levels of silica would allow for conditions favorable to the protection of ancient carbon-containing organic molecules, NASA said in a press release.

“One never knows what to expect on Mars, but the Elk target was interesting enough to go back and investigate,” said Roger Wiens, a principal investigator from the Los Alamos National Laboratory in New Mexico.