Hydrogen isotopes reveal water leakage from the core
- 1State Key Laboratory of Precision Geodesy, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, China.
- 2National Geophysical Observatory at Mengcheng, University of Science and Technology of China, Hefei, China.
Abstract
Chemical heterogeneities in Earth’s deep mantle may record either preserved primordial reservoirs or later core-mantle exchange, but distinguishing between these origins remains challenging. Hydrogen isotopes offer a sensitive tracer, yet whether magma ocean crystallization could generate a deuterium-depleted deep reservoir has not been quantitatively evaluated. Here, we use machine learning–accelerated path-integral simulations to determine equilibrium hydrogen isotope fractionation between silicate melt and bridgmanite, ringwoodite, and wadsleyite under magma ocean conditions. Incorporating these fractionation factors into a magma ocean crystallization model shows that mineral-melt fractionation is intrinsically weak, producing an essentially homogeneous D/H distribution in the primitive mantle. Magma ocean crystallization therefore cannot generate the extremely low δD values observed in some ocean island basalts. Combined with exceptionally high 3 He/ 4 He ratios, these signatures more plausibly reflect selective transfer of primordial volatiles from Earth’s core, implying sustained volatile exchange across the core-mantle boundary.
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BibTeX
@article{zhang2026hydrogen,
title = {{Hydrogen isotopes reveal water leakage from the core}},
author = {Yu Zhang and Wenzhong Wang and Zhongqing Wu and Bowen Chen},
journal = {Science Advances},
year = {2026},
month = oct,
doi = {10.1126/sciadv.aei4756},
url = {https://www.science.org/doi/10.1126/sciadv.aei4756},
note = {CC BY-NC},
}
RIS
TY - JOUR
TI - Hydrogen isotopes reveal water leakage from the core
AU - Yu Zhang
AU - Wenzhong Wang
AU - Zhongqing Wu
AU - Bowen Chen
PY - 2026
DA - 2026/10/09
JO - Science Advances
DO - 10.1126/sciadv.aei4756
UR - https://www.science.org/doi/10.1126/sciadv.aei4756
AB - Chemical heterogeneities in Earth’s deep mantle may record either preserved primordial reservoirs or later core-mantle exchange, but distinguishing between these origins remains challenging. Hydrogen isotopes offer a sensitive tracer, yet whether magma ocean crystallization could generate a deuterium-depleted deep reservoir has not been quantitatively evaluated. Here, we use machine learning–accelerated path-integral simulations to determine equilibrium hydrogen isotope fractionation between silicate melt and bridgmanite, ringwoodite, and wadsleyite under magma ocean conditions. Incorporating these fractionation factors into a magma ocean crystallization model shows that mineral-melt fractionation is intrinsically weak, producing an essentially homogeneous D/H distribution in the primitive mantle. Magma ocean crystallization therefore cannot generate the extremely low δD values observed in some ocean island basalts. Combined with exceptionally high 3 He/ 4 He ratios, these signatures more plausibly reflect selective transfer of primordial volatiles from Earth’s core, implying sustained volatile exchange across the core-mantle boundary.
SN - 2375-2548
ER -