Elucidating the environment and surface area environment of the early Earth, especially before the origin of life, is vital for understanding the habitability of the Earth. Ehime University in Japan led an experimental research study revealing that the development performance of Fe3+ through redox disproportionation of Fe2+ in metal-saturated magma under high pressures corresponding to the depth of the lower mantle is greater than formerly believed. The speculative results show that the Fe3+ material of the Earths magma ocean throughout core development was about one order of magnitude higher than the present upper mantle.
Research has provided new insights into the environment of early Earth, recommending it was formed by degassing volatiles from a magma ocean with a greater oxidation state than formerly thought. The research study found that the early Earths magma ocean had 10 times the Fe3+ material these dayss upper mantle, leading to an environment abundant in CO2 and SO2.
New research suggests early Earth had a highly oxidized magma ocean, leading to a CO2 and SO2-rich environment. The subsequent accretion of lowering materials was critical for creating a habitable environment.
Clarifying the atmosphere and surface environment of the early Earth, specifically before the origin of life, is essential for understanding the habitability of the Earth. The atmosphere of terrestrial planets has actually been believed to be formed by degassing volatiles from the interior and its structure is generally controlled by the oxidation state of the mantle. To understand the mantle oxidation state, the abundance of ferrous (Fe2+) and ferric (Fe3+) iron in the mantle are crucial since the mantle oxidation state varies with the relative abundance of these two iron oxides.
The bright area at the center of the image shows satiated metallic melt and the surrounding grey area indicates satiated silicate melt. The sample was encapsulated into a graphite pill, which is transformed into diamond throughout heating experiments. Credit: Geodynamics Research Center, Ehime University
Mantle Oxidation State and Research Findings
Ehime University in Japan led a speculative study showing that the development effectiveness of Fe3+ through redox disproportionation of Fe2+ in metal-saturated lava under high pressures representing the depth of the lower mantle is higher than previously thought. In this response, Fe3+ and metal iron (Fe0) are formed from 2Fe2+, and the segregation of Fe0 into the core increases the content of Fe3+ in the recurring lava and its oxidation state. The speculative outcomes indicate that the Fe3+ material of the Earths lava ocean during core development had to do with one order of magnitude greater than today upper mantle.
Implications for Early Earths Magma Ocean
This recommends that the lava ocean was much more oxidizing than the present Earths mantle after the core formation, and the environment formed by the degassing of volatiles from such an extremely oxidizing lava would have been abundant in CO2 and SO2.
In addition, the authors found that the estimated oxidation state of the Earths magma ocean can discuss that of Hadean lavas of more than 4 billion years back by inference from geological records. Because the formation efficiency of biomolecules in a CO2-rich atmosphere is quite low, the authors hypothesized that the late accretion of decreasing products after the development of the Earth played an essential function in supplying biologically offered organic particles and the development of a habitable environment.
Reference: “Hadean mantle oxidation presumed 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.
Funding: Japan Society for the Promotion of Science.
