Debate over signs of early life inspires dueling teams to go to Greenland — together
Deep in the heart of Greenland, in an area recently laid bare by melting ice, lies a controversy: A rocky outcrop that some scientists say contains the oldest known signs of life on Earth. Others disagree. So a handful of scientists recently headed to the site to study it together. It’s not easy to identify biological traces within rocks that have been churned and chewed by tectonic pressure and heat over billions of years. But figuring out how best to identify such traces on Earth could help scientists spot those signs on other worlds, such as Mars. The Greenland outcrop, which dates to between 3.7 billion and 3.8 billion years ago, contains strange squiggles just a few centimeters tall. One team of scientists has suggested the wavy pattern was shaped by microbes living in ancient shallow pools (SN: 8/31/16). The microbes shifted sediments until they formed thinly layered structures called stromatolites, geologist Allen Nutman of the University...