To help resolve thisdiscrepancy, scientistsinvestigatedancientrocksfrom Isua, Greenland, toseehow the planetchangedovertimeandwhenpreciousmetalsentered the picture.
In 1999, Danish geologist Minik Rosing presented evidence of a chemical signature for primitive lifeforms in 3.7-billion-year-old rocks from Isua, Greenland.