A recent investigation reveals that the magma ocean of the primordial Earth was substantially more oxidized, resulting in an atmosphere abundant in CO2 and SO2. This condition may have inhibited the creation of biomolecules, indicating that the later addition of reducing substances was vital for making the planet habitable.
The latest research provides insights into the makeup of Earth’s initial atmosphere.
Grasping the atmospheric and ground circumstances of early Earth, particularly prior to the genesis of life, is essential for understanding Earth’s capability to nurture life. The atmosphere of terrestrial planets is thought to have originated from the discharge of volatile compounds from within the planet, and its primary constitution is governed by the mantle’s oxidation condition.
To grasp this oxidation state within the mantle, recognizing the quantity of ferrous (Fe2+) and ferric (Fe3+) iron is vital, as the oxidation level of the mantle fluctuates with the proportional quantities of these two forms of iron oxides.
A study spearheaded by Ehime University has experimentally proven that the conversion efficiency of Fe3+ through redox disproportionation of Fe2+ in metal-infused magma at elevated pressures corresponding to the lower mantle’s depth is greater than previously estimated. In this chemical process, Fe3+ and elemental iron (Fe0) evolve from 2Fe2+, and the segregation of Fe0 into the core augments the concentration of Fe3+ in the remaining magma, thus enhancing its oxidation state.
The image’s central bright region displays quenched metallic melt, while the encircling grey area signifies quenched silicate melt. The specimen was enclosed in a graphite container, which turned into diamond during heating experiments. Credit goes to Geodynamics Research Center, Ehime University.
The trial results suggest that the Earth’s magma ocean’s Fe3+ content at the time of core creation was approximately tenfold higher than the existing upper mantle. This implies that the magma ocean was far more oxidizing than today’s Earth’s mantle after core formation, and the atmosphere emanating from the degassing of such an intensively oxidizing magma would have been saturated with CO2 and SO2.
Moreover, the researchers discovered that the evaluated oxidation level of Earth’s magma ocean aligns with that of Hadean magmas dating back over 4 billion years, as deduced from geological evidence.
Due to the limited formation efficiency of biomolecules in an atmosphere rich in CO2, the study’s authors theorized that the subsequent incorporation of reducing elements following Earth’s formation was instrumental in providing accessible organic molecules for biological use and in shaping a livable environment.
Reference: “Hadean mantle oxidation inferred from melting of peridotite under lower-mantle conditions” by Hideharu Kuwahara, Ryoichi Nakada, Shintaro Kadoya, Takashi Yoshino, and Tetsuo Irifune, 4 May 2023, Nature Geoscience. DOI: 10.1038/s41561-023-01169-4
The research was financially supported by the Japan Society for the Promotion of Science.
Table of Contents
Frequently Asked Questions (FAQs) about fokus keyword: early Earth’s magma
What does the new study reveal about early Earth’s magma?
The study shows that the magma ocean of primordial Earth was substantially more oxidized, leading to an atmosphere abundant in CO2 and SO2. This condition could have hindered the creation of biomolecules, indicating that the later addition of reducing substances was vital for making Earth habitable.
What was the significance of the findings related to Fe2+ and Fe3+?
Understanding the abundance of ferrous (Fe2+) and ferric (Fe3+) iron in the mantle is key to grasping the mantle’s oxidation state. The experimental study led by Ehime University found that the formation efficiency of Fe3+ in metal-infused magma at lower mantle’s depth is higher than previously thought, affecting the oxidation state of the residual magma.
How does this research contribute to understanding Earth’s habitability?
This research offers insights into Earth’s earliest atmospheric composition, suggesting that the magma ocean was more oxidizing, with an atmosphere rich in CO2 and SO2. This could have inhibited biomolecule formation, making the later addition of reducing materials crucial for the formation of a habitable environment.
What does the image described in the text depict?
The image’s central bright region displays quenched metallic melt, and the surrounding grey area signifies quenched silicate melt. The sample was enclosed in a graphite container and transformed into diamond during heating experiments.
Who funded the study, and where was it published?
The study was financially supported by the Japan Society for the Promotion of Science and was published in Nature Geoscience with a DOI of 10.1038/s41561-023-01169-4.
4 comments
dont know much about geology, but this sounds important. So the earth was more oxidized before? Need to read up more on this!
Really interesting study. early earth always fascinated me. Keep up the good work!
Wow, this is an eye-opener. Changes the way we look at our planets history. Where can I find more stuff like this?
It’s amazing how studies like this shed light on something so old and distant like earth’s early mantle. I want to learn more, can someone recomend some books?