Isotopically heavy carbon in the core
Year: 2026
Type: article
Abstract: Constraining the origin of Earth’s carbon requires knowing the isotopic composition of the core—a geochemical signature long presumed to be beyond observation for the planet’s largest carbon reservoir. Here, we report high-precision δ 13 C measurements from Hawaiian plume melt inclusions entrapped before significant degassing and sampling distinct mantle sources. Melt inclusions from shield-stage lavas, interpreted to sample the plume’s central axis, inferred to be rooted in the core–mantle boundary thermal boundary layer, converge toward a primary δ 13 C signature of –1 ± 2‰. In contrast, melt inclusions from rejuvenated-stage lavas, derived from entrained mantle at the plume’s periphery, record a normal mantle source signature of –7 ± 2‰. We interpret the uniquely 13 C-rich shield-stage signature as the isotopic fingerprint of carbon exchanged from the core into the mantle. Our results point to 13 C-rich carbonaceous chondrites as the primary source of Earth’s carbon.
Institutions: American Museum of Natural History, Lamont-Doherty Earth Observatory, Columbia University, Yale University, Centre National de la Recherche Scientifique, Institut des Sciences de la Terre d'Orléans, United States Geological Survey, Cascades Volcano Observatory, University of Oregon, University of Hawaiʻi at Mānoa, Brown University, University of California, Santa Barbara
Language: English
Subfield: Geochemistry and Petrology
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: hybrid
OpenAlex ID: W7225658916