Zinc isotope anomalies reveal accretion of outer solar system material during Earth formation
The question of the origin of volatile elements* present on Earth is fundamental to understanding the evolution of our planet. A study carried out at IPGP-Université Paris Cité has revealed the first zinc isotope anomalies in different types of meteorites and on Earth.
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Publication date: 28/06/2022
Press, Research
Related teams :
Cosmochemistry, Astrophysics and Experimental Geophysics (CAGE)
Related themes : Origins
Carbonaceous (CC) meteorites from the outer Solar System and non-carbonaceous (NC) meteorites from the inner Solar System have distinct isotope ratios, a fact known for several refractory elements** but never before observed for a moderately volatile element such as zinc.
While our planet has isotopic ratios of refractory elements similar to some NC meteorites (enstatite chondrites), zinc isotopic ratios fall between NC and CC meteorites. This result reveals that a significant fraction (30%) of terrestrial zinc was captured during the accretion of CC meteorites. As CC meteorites are richer in zinc and other volatile elements than NC meteorites, this implies that the Earth must have accreted 5-6% of its overall mass from CC material, presumably from the outer Solar System.
Ref : P.S. Savage, F. Moynier and M. Boyet, Zinc isotope anomalies in primitive meteorites identify the outer solar system as an important source of Earth’s volatile inventory, Icarus (2022), DOI: 10.1016/j.icarus.2022.115172
* Chemical elements associated with a planet’s crust or atmosphere, characterized by low boiling temperatures and therefore easily sublimated (hydrogen, carbon, rare gases, halogens, sulfur).
** Chemical elements with high boiling points (titanium, chromium, calcium, molybdenum).
