Researchers at Imperial College London studied meteorites to determine the origin of Earth’s volatile chemicals. They discovered that half of Earth’s zinc came from asteroids that originated beyond the asteroid belt, which includes Jupiter, Saturn, and Uranus. This material is also thought to have provided other important volatiles, such as water. The discovery suggests that the outer Solar System played a larger role than previously thought in establishing Earth’s inventory of volatile chemicals, and it may provide clues about the conditions required for life to emerge on Earth.

The study looked at 18 meteorites from various solar systems, 11 from the inner Solar System and 7 from the outer Solar System. The researchers compared the relative abundances of five different types of zinc in each meteorite to Earth samples. They discovered that, while carbonaceous bodies made up only about 10% of the Earth’s mass, they supplied roughly half of the zinc.

The researchers believe that material containing a high concentration of zinc and other volatile constituents is also likely to be relatively abundant in water, shedding light on the origins of Earth’s water. The findings suggest that carbonaceous material played a key role in establishing Earth’s budget of volatile elements, some of which are essential for life, according to the paper’s first author, PhD candidate Rayssa Martins.

The researchers intend to analyze rocks from Mars, which once had water, and the Moon next. According to senior author Professor Mark Rehkämper, analyzing zinc isotopes in moon rocks will help test the hypothesis that the Moon formed from a massive asteroid collision with an embryonic Earth, as well as determine whether the colliding asteroid delivered volatiles to Earth.

References

Brogan, C. (2023, January 27). Meteorites reveal likely origin of Earth’s volatile chemicals. Imperial News; Imperial College London. https://www.imperial.ac.uk/news/242771/meteorites-reveal-likely-origin-earths-volatile/

Martins, R., Kuthning, S., Coles, B. J., Kreissig, K., & Rehkämper, M. (2023). Nucleosynthetic isotope anomalies of zinc in meteorites constrain the origin of Earth’s volatiles. Science, 379(6630), 369–372. https://doi.org/10.1126/science.abn1021