The continental crust first appeared 3.7 billion years ago

In the Archean period, the reconstruction of the ascent and weathering of the continental crust was crucial for us to understand the early ocean chemistry, the evolution of the biosphere, and the beginning of plate tectonics.

An Artistic conception of the early Earth. Image Credit : Simone Marchi/NASA.

Once the earth is formed through dynamic processes such as plate tectonics. It begins to erode, adding important minerals and nutrients to the ocean.

The records of these nutrients are kept in ancient stone records. 

Previous studies have used strontium isotopes in marine carbonates, but these rocks are usually rare or disturbed in rocks older than 3 years. 

Desiree Roerdink, a geochemist at the University of Bergen, and her colleagues have developed a new method that can use another mineral: barite to track the first appearance of ancient rocks. 

Barite is made by mixing seawater sulfate with barium and barium in hydrothermal fluid. It has a reliable marine chemical record in its structure and can be used to reconstruct the destroyed ancient environment.

 "We collected the ingredients of a barite in the field for three years.

Dr. Roerdink said that 5 billion years ago, it was the real moment of collapse. In fact, this is a very good recorder for observing the process of the early earth.

Dr. Roerdink and his colleagues tested six different deposits on three different continents, ranging in age from 320 to 3.5 billion years. They calculated the ratio of strontium isotopes in the barite and inferred the time it takes for the weathered continental rock to reach the ocean and turn on the barite. According to new data, they found that weathering began about 3.7 billion years ago. 500 million years earlier than previous assumptions."This is a huge time. "It has a major impact on the way we think about our lifestyle. Roldink.

"Scientists usually think that life is formed in the depths of the ocean under hydrothermal conditions, but the biosphere is complicated. "We really don't know whether it is possible for life to appear on the earth at the same time, but this earth must be there. "After all, the rise of the earth illustrates the early emergence of plate tectonics and Geodynamics. "To obtain land, you need an effective process to form this continental crust, and a process to form a crust that is different from chemical substances. The crust of the ocean is different.