Earth's crust emerged 500 million years earlier than previously thought, research uncovers

Earth’s continental crust may have emerged 3.7 billion years earlier than scientists had previously estimated. A team of scientists has devised a new way to date ancient chunks of crust and according to their latest research, the age of the continents have been misjudged by half a billion years. A research presented at the virtual European Geosciences Union (EGU) General Assembly 2021 conference, the team showed that by analyzing a mineral called barite, which is a combination of ocean salts and barium released by volcanic ocean vents, they found evidence that Earth’s continental crust was around at least 3.7 billion years ago, much older than previous estimates. 

The research author Desiree Roerdink, a geochemist at the University of Bergen, Norway, said that this is a “huge” jump back in time. "It has implications for the way that we think about how life evolved. We don’t really know if it is possible that life could have developed at the same time on land,” Roerdink noted, adding “but then that land has to be there.”

According to the research, continents and oceans have a long history of trading nutrients - and barites record that history extremely well. Roerdink informed that the composition of a piece of barite that has been on Earth for three and a half billion years is exactly the same as it was when it actually precipitated. She added that it is a great recorder to look at processes on the early Earth. 

Further, during the virtual conference, the team explained that the key process is weathering. They explained that as continents wear down naturally over time, they spill nutrients into the neighbouring seas. These nutrients help foster life in the seas. The team of researchers then went on to say that one element that continental crust leaks into the ocean is strontium. 

(Image: EGU/Website)

500mn years earlier than previously thought

They said that by measuring the ratio of two strontium isotopes in six different deposits of barite minerals, they calculated the ages of those minerals. The mineral ranged from 3.2 billion to 3.5 billion years old. But the story doesn’t end there, as the team explained that from these minerals, they inferred how long ago the ancient continents started leaking strontium into the oceans where these barites eventually formed. This continental weathering process likely began about 3.7 million years ago, the concluded. 

The recent research means that there were well-established continents around 3.7 billion years ago, which is 500 million years earlier than previously thought. The researchers said that the finding means that the process that creates continents - such as place tectonics - have been active on Earth for at least that long. There could also be implications for the evolution of life in the ocean, which thrived on those continental nutrients, the researchers said, however, they also added that more research is required to know for sure. 

(Image: Unsplash)