Magnetic traces have long been used to calculate the latitudes, the north - south positions, of ancient continents. (discovermagazine.com)
These gems, brought to the surface by volcanic eruptions, were uncovered in five ancient continents by researchers over the course of more than 30 years. (livescience.com)
Researchers analyzed the levels of various trace elements in hundreds of samples of carbon - rich shales that had been deposited in oxygen - poor regions of the ocean surrounding ancient continents during the past 3.5 billion years. (sciencemag.org)