Researchers have uncovered ancient sand in the Northwest Territories that they say provides new evidence about a continent 3.2 billion years old that no longer exists.
In a study published in the journal Geology, scientists from the University of Alberta detailed their discovery of mineral grains called chromite – a crystallized form of volcanic lava – preserved in 2.85-billion-year-old sandstone in the NWT’s Slave Craton.
“I was very surprised,” Rasmus Haugaard, lead author of the study and a former PhD student at the University of Alberta, told Cabin Radio.
“We haven’t found those rocks in the Slave Craton yet … that’s pretty amazing, I think.”
Hauguaard explained that cratons are the “building blocks” of the first continents on Earth. The Slave Craton, located in the northwestern Canadian shield in the NWT and Nunavut, is home to Earth’s oldest known surviving rock – the Acasta Gneiss.
Hauguaard said the newly discovered mineral grains would have come from an “ultra-high temperature” volcanic eruption, then travelled down rivers to reach the sandy shoreline billions of years ago. He said they “represent an important piece” of how ancient continental land masses formed.
“Our research developed a method to identify and date pieces of our ancient continent that until now has been lost to us, due to weathering or whatever mechanism that destroyed the rocks,” he said.
“I think if we develop this method even more … we can get a clearer, more complete picture of our ancient continents.”
Hauguaard noted that without these stable continental landmasses, we probably wouldn’t have the life that we know today.