Researchers examine some of the world’s oldest colored stones University of Waterloo Carbon remains of what was once ancient life encrusted with a 2.5-billion-year-old gem have been discovered.
A research team led by Chris Yakimchuk, Professor of Earth and Environmental Sciences at Waterloo, began studying gem geography to better understand the conditions required for ruby to form. During this research in Greenland, which contains deposits of the world’s oldest gemstones, the team discovered a sample of sapphire containing the mineral graphite made from pure carbon. Analysis of this carbon indicates that it is a relic of early life.
“The graphite inside this sapphire is really unique. This is the first time we see evidence of ancient life in the gem,” Yakimsuk says. “The presence of graphite gives additional clues as to how the gem was formed in this location, something that cannot be done directly based on the color and chemical composition of sapphire.”
The presence of graphite allowed the researchers to study a property called the isotopic structure of carbon atoms, which measures the relative sizes of different carbon atoms. More than 98 percent of all carbon atoms contain 12 atomic mass units, but a few carbon atoms are heavier with 13 or 14 atomic mass units.
“Living matter contains lighter carbon atoms because it takes less energy to attach to cells,” Yakimchuk said. “Based on the increased levels of carbon-12 in this graphite, we concluded that carbon atoms were once an ancient life form, mostly dead microorganisms such as cyanobacteria.”
Graphite was found in ancient rocks 2.5 billion years ago, a time period when there was not much oxygen in the atmosphere, and life existed only in films of microbes and algae.
During this study, Yakimsuk’s team discovered that this graphite gem is not only related to ancient life, but is also essential to the existence of this gem. Ruby changed the chemistry of the surrounding graphite rocks to create favorable conditions for growth. Without it, the team’s models showed that no gem would have been created in this space.
Development of corundum (ruby) during the last meeting of the Groton Arche of the North Atlantic in Southwest Greenland”. Geological reviews of minerals. A complementary study has been published in the journal Corundum Puzzle: Controling Ruby Forming Fluids in the Transformation Melanches of Ultramorphic and Aluminum Rocks. chemistry geography in June.
Chris Yakimsuk, Vincent Van Hensburg, Christopher L. Kirkland, Christopher Silas, Carson Kinney, Gillian Kendrick and Julie A. Hollis, 20 Geological reviews of minerals.
DOI: 10.1016 / j.oregeorev.2021.104417
Vincent van Hensburg, Chris Jakimchuk and Angkovac Thomas Gilliest Jepsen, Christopher L. Kirkland and Christopher Silas, 2020 2020. chemistry geography.
DOI: 10.1016 / j.chemgeo.2021.120180