reporter learned from on the 8th that Professor Wu Zhongqing's research team of the School of Earth and Space Sciences of the school, through first-principle calculations, found that in the solar nebula environment, the melting and volatility process of early planetary embryos (partially) in the early stage of planetary hyperplasia is the main cause of the earth's volatile elements, and provides important inspiration for the study of the hyperplasia and evolution of volatile matter of in the solar nebula environment. The research results were recently published in the international journal Nature Earth Science.
The volatile elements of the earth are crucial to the formation, evolution and habitability of planets. Their proliferation process is a difficult issue that has long been concerned about in the field of Earth and planetary science research. The study found that the earth has similar abundance of difficult-to-volatile elements compared to the material composition of the early solar system, but it is very loss of volatile elements. At present, the academic community has been controversial about the source of volatile elements on the earth and their hyperplasia. Since early Earth records are rarely retained, it is difficult to directly study the evolutionary history of Earth's volatiles through early geological samples.
Researchers obtained high-quality inter-mantle sulfur isotope fractionation coefficient based on the first principle calculation of density functional theory , and found that the sulfur isotope fractionation caused by nucleus mantle separation is almost negligible, which means that the later hyperplasia model and nucleus mantle separation cannot explain that silicate Earth has a lower sulfur isotope ratio than chondrite , and the earth as a whole has the same sulfur isotope composition as its silicate part. Combined with thermodynamics calculation and first-principle calculation, the researchers found that when the hydrogen gas was not completely dissipated in the early solar system, the star embryos were partially melted, and sulfur mainly evaporated in the form of hydrogen sulfide , and took away heavy sulfur isotopes, making the residual silicate enriched for light sulfur isotopes. About 90% of the original hyperplastic sulfur volatility can quantitatively explain the low sulfur isotope ratio of the Earth, and it can also explain the sulfur content of the Earth. In addition, during the formation of the moon by a large collision, a large amount of sulfur is further lost, but due to the different formation environments, the loss of sulfur will take away light sulfur isotopes, making the moon have a heavier sulfur isotope composition than the earth.
This study shows that the earth originated from volatile matter, and early volatility is the key to establishing the composition of volatile elements on the earth today, which provides a new perspective for the academic community to study the origin of volatile matter in Earth-like planets.
text/Science and Technology Daily reporter Wu Changfeng
edited by Fan Hui
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