Substantial carbon dioxide release from subducted dolomitic carbonate driven by episodic infiltration of eclogite-facies fluids
Bibliographic record
Abstract
Abstract The mechanism and efficiency of CO2 release from subducting carbonates lie at the heart of quantifying carbon cycling in subduction zones. Most previous studies focused on CO2 release from calcite/aragonite, while decarbonation behavior of another critical carbonate—dolomite—is poorly constrained. Here, we investigated reaction veins and zones in dolomitic marbles from the Dabie ultrahigh-pressure (UHP) terrane, China. Petrology, geochemistry, O-C isotopes, and U-Pb dating reveal that the reaction veins and zones record the metasomatic interaction of dolomitic marbles with episodic Si-Al-Ti–bearing aqueous fluids from UHP eclogites and substantial release of CO2. Mass-balance calculations indicate that 67%–84% of initial CO2 was released from the altered marbles, whereas the losses of Ca (34%–67%) and Mg (almost immobile) are much lower, suggesting that CO2 removal was not caused by simple (bulk) dissolution of dolomite. Instead, it reflects that ~50% of initial CO2 was removed via replacement reactions of dolomite by Mg-silicates + CaCO3, and another ~17%–34% CO2 extraction was by dissolution of reaction-formed CaCO3. Enrichment of solutes (e.g., Si and Al) in slab fluids facilitates the decarbonation by solute load in fluid-dolomite interactions, and pulsed fluid infiltration helps enhance CO2 liberation. Considering the wide presence of dolomite in subducted slabs and its high decarbonation efficiency during fluid infiltration, the findings highlight that slab dolomite plays a significant role in carbon release from subduction zones.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".