THE SUB-ARC MANTLE HAS REMAINED OXIDIZED SINCE THE NEOPROTEROZOIC OXYGENATION EVENT
Seminars
Summer Semester
Chun-Tao Liu is a postdoctoral researcher at the Research Center for Earth and Planetary Material Sciences, School of Earth Sciences, Zhejiang University. He obtained his Ph.D. in Earth Sciences from Zhejiang University in 2024. Leveraging global geochemical datasets of igneous rocks, he utilizes statistical analysis and machine learning techniques to explore the evolution of Earth's crustal geochemical composition, mantle oxygen fugacity, continental uplift, plate tectonics, and the planet's habitability. He has published four first-author papers in Geochemical Perspectives Letters (2) and Geophysical Research Letters (2), with a paper accepted in Nature Communications. He is currently supported by the Postdoctoral Fellowship Program of CPSF.
For additional information, please contact Prof. Weiran Li, weiranli@hku.hk.
The formation of arc volcanoes and related ore deposits is strongly influenced by the redox state of the sub-arc mantle, yet the evolution of the sub-arc mantle's oxygen fugacity (fO₂) during the Neoproterozoic Oxygenation Event (NOE, ~0.8–0.4 Ga) has remained unclear. This presentation will introduce our research, which employed machine learning to identify arc basalts and analyzed the V/Sc ratio—an effective indicator of mantle oxygen fugacity—in primitive arc basalts over the past 800 million years. Our findings reveal that this ratio has remained stable at 7.16 ± 0.91, indicating that the sub-arc mantle has maintained an oxidized state since ~0.8 Ga. This stability suggests that the increase in surface oxygen levels during the NOE did not directly oxidize the sub-arc mantle; instead, its oxidation is more likely related to oxidized fluids and melts brought by subducted serpentinized oceanic crust. Although this long-term oxidized state has controlled the redox characteristics of arc magmas and influenced the long-term oxidation of Earth's surficial environments since the NOE, it was not the primary driver of the NOE.