Formation of Structurally Bound Carbonate in Silicate Melts on the Top of the Mantle Transition Zone

Abstract Carbon‐bearing dense silicate melts may account for the seismically weak layers on top of the mantle transition zone (MTZ) at 13–14 GPa. How carbon is incorporated into silicate melts at such high pressures has not been experimentally probed, making the nature of carbon in dense melts elusi...

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Main Authors: Eun Jeong Kim, Sung Keun Lee
Format: Article
Language:English
Published: Wiley 2025-02-01
Series:Geophysical Research Letters
Subjects:
Online Access:https://doi.org/10.1029/2024GL113755
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author Eun Jeong Kim
Sung Keun Lee
author_facet Eun Jeong Kim
Sung Keun Lee
author_sort Eun Jeong Kim
collection DOAJ
description Abstract Carbon‐bearing dense silicate melts may account for the seismically weak layers on top of the mantle transition zone (MTZ) at 13–14 GPa. How carbon is incorporated into silicate melts at such high pressures has not been experimentally probed, making the nature of carbon in dense melts elusive. Here, our nuclear magnetic resonance experiments reveal how carbon and pressure influence the structure of mantle melts. The pressure‐driven changes in the Si coordination environments and network connectivity in dense melts are accompanied by a dramatic increase in the fraction of structurally bound carbonates above 8 GPa up to 14 GPa, further polymerizing melt networks. The pressure‐driven melt polymerization and increase in diversity in carbon configurations reveal the mechanisms behind the pressure‐induced propensity to store carbon in silicate melts under compression. The substantial carbon incorporation in silicate melts toward the MTZ may potentially filter out the carbon from subducting slabs, controlling the deep carbon cycle.
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spelling doaj-art-6743e9104f604478b36115194ae03f242025-08-20T02:52:30ZengWileyGeophysical Research Letters0094-82761944-80072025-02-01523n/an/a10.1029/2024GL113755Formation of Structurally Bound Carbonate in Silicate Melts on the Top of the Mantle Transition ZoneEun Jeong Kim0Sung Keun Lee1School of Earth and Environmental Sciences Seoul National University Seoul KoreaSchool of Earth and Environmental Sciences Seoul National University Seoul KoreaAbstract Carbon‐bearing dense silicate melts may account for the seismically weak layers on top of the mantle transition zone (MTZ) at 13–14 GPa. How carbon is incorporated into silicate melts at such high pressures has not been experimentally probed, making the nature of carbon in dense melts elusive. Here, our nuclear magnetic resonance experiments reveal how carbon and pressure influence the structure of mantle melts. The pressure‐driven changes in the Si coordination environments and network connectivity in dense melts are accompanied by a dramatic increase in the fraction of structurally bound carbonates above 8 GPa up to 14 GPa, further polymerizing melt networks. The pressure‐driven melt polymerization and increase in diversity in carbon configurations reveal the mechanisms behind the pressure‐induced propensity to store carbon in silicate melts under compression. The substantial carbon incorporation in silicate melts toward the MTZ may potentially filter out the carbon from subducting slabs, controlling the deep carbon cycle.https://doi.org/10.1029/2024GL113755deep carbon cyclelow‐velocity layermantle transition zonesolid‐state NMRsilicate melts under compression
spellingShingle Eun Jeong Kim
Sung Keun Lee
Formation of Structurally Bound Carbonate in Silicate Melts on the Top of the Mantle Transition Zone
Geophysical Research Letters
deep carbon cycle
low‐velocity layer
mantle transition zone
solid‐state NMR
silicate melts under compression
title Formation of Structurally Bound Carbonate in Silicate Melts on the Top of the Mantle Transition Zone
title_full Formation of Structurally Bound Carbonate in Silicate Melts on the Top of the Mantle Transition Zone
title_fullStr Formation of Structurally Bound Carbonate in Silicate Melts on the Top of the Mantle Transition Zone
title_full_unstemmed Formation of Structurally Bound Carbonate in Silicate Melts on the Top of the Mantle Transition Zone
title_short Formation of Structurally Bound Carbonate in Silicate Melts on the Top of the Mantle Transition Zone
title_sort formation of structurally bound carbonate in silicate melts on the top of the mantle transition zone
topic deep carbon cycle
low‐velocity layer
mantle transition zone
solid‐state NMR
silicate melts under compression
url https://doi.org/10.1029/2024GL113755
work_keys_str_mv AT eunjeongkim formationofstructurallyboundcarbonateinsilicatemeltsonthetopofthemantletransitionzone
AT sungkeunlee formationofstructurallyboundcarbonateinsilicatemeltsonthetopofthemantletransitionzone