@article{f80dbb86c4954365982204d9b90f9844,
title = "Insufficient Energy From MgO Exsolution to Power Early Geodynamo",
abstract = "The origin of Earth's ancient magnetic field is an outstanding problem. It has recently been proposed that exsolution of MgO from the core may provide sufficient energy to drive an early geodynamo. Here we present new experiments on Mg partitioning between iron-rich liquids and silicate/oxide melts. Our results indicate that Mg partitioning depends strongly on the oxygen content in the iron-rich liquid, in contrast to previous findings that it depends only on temperature. Consequently, MgO exsolution during core cooling is drastically reduced and insufficient to drive an early geodynamo alone. Using the new experimental data, our thermal model predicts inner core nucleation at ~850 Ma and a nearly constant paleointensity.",
keywords = "core dynamo, elemental partitioning, high pressure, laser-heated diamond anvil cell, magnetic field, paleomagnetism",
author = "Zhixue Du and Colin Jackson and Neil Bennett and Peter Driscoll and Jie Deng and Lee, {Kanani K.M.} and Eran Greenberg and Prakapenka, {Vitali B.} and Yingwei Fei",
note = "Funding Information: Data supporting Figure S1 are available in supporting information Table S1. We thank Emma Bullock for electron microprobe analysis, Suzy Vitale for FIB operations, and Victor Lugo for machining at Carnegie Institution of Washington. We also thank Sz-Chian Liou at University of Maryland and Fernando Camino at Brookhaven National Lab for help with FIB operations. We thank Timothy Strobel and Alexander Goncharov{\textquoteright}s generosity for sharing laser systems and other facilities. Special thanks for Jiachao Liu and Jie Li for donating a carbon standard and Stephen Elardo for synthesizing the basalt glass. We also thank Anat Shahar, Miki Nakajima, Renbiao Tao, Megan Duncan, and James Badro for discussions. We appreciate two anonymous reviewers for critical comments. Z. Du, C. Jackson, and N. Bennett thank the Carnegie Fellowship for financial support. The research is supported by NSF grant (EAR-1447311) to Y. Fei. Work at Yale University is supported in part by NSF grants (EAR-1321956 and EAR-1551348) to K. K. M. Lee. Portions of this work were performed at GeoSoilEnviroCARS (University of Chicago, Sector 13), Advanced Photon Source (APS), Argonne National Laboratory. GeoSoilEnviroCARS is supported by the National Science Foundation-Earth Sciences (EAR-1128799) and Department of Energy-GeoSciences (DE-FG02-94ER14466). This research used resources of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under contract DE-AC02-06CH11357. Publisher Copyright: {\textcopyright}2017. American Geophysical Union. All Rights Reserved.",
year = "2017",
month = nov,
day = "28",
doi = "10.1002/2017GL075283",
language = "English (US)",
volume = "44",
pages = "11,376--11,381",
journal = "Geophysical Research Letters",
issn = "0094-8276",
publisher = "American Geophysical Union",
number = "22",
}