Researchers have used the chemical fingerprints of zinc contained in meteorites to determine the origin of volatile elements on Earth. The results suggest that without ‘unmelted’ asteroids, there may not have been enough of these compounds on Earth for life to emerge.

The researchers, from the University of Cambridge and Imperial College London, have previously found that Earth’s zinc came from different parts of our solar system: about half came from beyond Jupiter and half originated closer to Earth…

Planetesimals are the main building blocks of rocky planets, such as Earth. These small bodies are formed through a process called accretion, where particles around a young star start to stick together, and form progressively larger bodies…

The researchers measured the zinc from a large sample of meteorites originating from different planetesimals and used this data to model how Earth got its zinc, by tracing the entire period of the Earth’s accretion, which took tens of millions of years.

Their results show that while these ‘melted’ planetesimals contributed about 70% of Earth’s overall mass, they only provided around 10% of its zinc.

According to the model, the rest of Earth’s zinc came from materials that didn’t melt and lose their volatile elements. Their findings suggest that unmelted, or ‘primitive’ materials were an essential source of volatiles for Earth.

Source:

Primitive asteroids as a major source of terrestrial volatiles

https://www.science.org/doi/10.1126/sciadv.ado4121