Discovering ancient settlements is often rather hit and miss, but the odds would be improved with a bit of chemical analysis. Plants growing over old sites of human habitation have a different chemistry from their neighbours, and these differences can reveal the location buried ruins.
Plants mostly take in nitrogen from the soil as the isotope nitrogen-14, with just a dash of nitrogen-15. Plants growing above archaeological sites in Greenland, however, seem to have absorbed a larger dose of nitrogen-15.
Rob Commisso and Erle Nelson from Simon Fraser University in British Columbia, Canada, spent three summers collecting plants from sites…
