"In searching for the earliest life on Earth and other worlds, researchers normally look for intact fossils or biomolecules made only by living organisms. But such signals are few and far between. Now, researchers have devised an artificial intelligence (AI) that can identify signs of ancient life in rocks of unknown provenance, based only on the pattern of chemicals left behind as biomolecules degrade over eons."
https://www.science.org/content/article/ai-spots-ghost-signatures-ancient-life-earth
Ancient chemical clues reveal Earth’s earliest life 3.3 billion years ago
https://www.science.org/content/article/ai-spots-ghost-signatures-ancient-life-earth
Ancient chemical clues reveal Earth’s earliest life 3.3 billion years ago