Scientists have found 3.6 billion-year-old zircon minerals in the Jack Hills, a mountain range in the midwest of Western Australia. Geologists believe that these minerals are evidence of how modern plate tectonics emerged. These zircons are the latest in a series of pieces of evidence that confirm the plate tectonics theory, the most explanatory geological theory that explains how earth transformed from a molten ball of fire to the mother of life. It also explains how tectonic plates — pieces of earth’s crust — moved over the rocky and viscous mantle to eventually form mountains and oceans.
“We analyzed thousands of these crystals to come up with a handful of useful data points, but each sample has the potential to tell us something completely new and reshape how we understand the origins of our planet,” said Michael Ackerson, the geologist who led the study that was published in Geochemical Perspectives Letters journal on March 19, 2021. His statement was published in a news release by Smithsonian's National Museum of Natural History, the organisation Ackerson works with.
Ackerson and his research team went to Jack Hills to collect 15 grapefruit-sized rocks and brought them back to grind and extract the minerals — zircons — from them. Among the 3500 sample crystals of the mineral, 200 were found to fit the study requirements. The zircons contained the radioactive metal Uranium which helped scientists trace the origin of the zircons. The rate of decay of Uranium is well quantified so the age of zircon minerals could be obtained by studying the decaying Uranium trapped in the minerals.
The minerals also contained aluminium which can help scientists grasp what might have been going on with the earth’s geology during the formation of the zircons. They found that around 3.6 billion years ago, there was a considerable increase in the concentrations of aluminium, a compositional shift that “potentially could signal the emergence of life on Earth,” according to Ackerson.
The geologist agreed that a lot more research needs to be carried out to determine this geologic shift's connections to the origins of life.