Geochemical and C‐O Isotopic Study of Ophiolite‐Derived Carbonates of the Barzaman Formation, Oman: Evidence of Natural CO<sub>2</sub> Sequestration Via Carbonation of Ultramafic Clasts
Bibliographic record
Abstract
Abstract Carbonate precipitation through atmospheric CO2 uptake by alkaline‐hyperalkaline waters offers a potential approach to mitigating anthropogenic CO2 emissions. The Oman Ophiolite produces high‐pH water characterized by continuous sequestration of CO2 at the air‐water interface. The geochemical and isotopic data of carbonates from the Barzaman Formation is used to assess the amount of atmospheric CO2 stored in the dolomite‐calcite assemblage. Post Archean Australian Shale ‐normalized rare earth elements patterns, with the exception of La and Ce anomalies, are similar to those of the bulk oceanic and lower crusts, with increasing LREE and flat HREE trends, and a positive Eu anomaly. The δ13CVPDB and δ18OVSMOW isotope values of the analyzed samples show two distinct end‐members, in which dolomite (−7.77‰ and +27.3‰) is isotopically heavier than calcite (−9.93‰ and +21.5‰). The estimated carbonate growth temperatures (18°C–56°C) are indistinguishable from the previously reported range (18°C–66°C). The C‐O isotope model for calcite, groundwater, and atmospheric CO2 shows that an ophiolite‐derived calcite sample absorbed an unequivocal amount of atmospheric CO2 (78% ± 11%) during precipitation. At the same time, dissolved inorganic carbon (DIC) in water accounts for the remaining carbon contribution (22% ± 9%). DIC is closely associated with different carbonate lithofacies and ophiolite‐derived soil, exhibiting large variations in C‐O isotopic compositions caused by isotopic disequilibrium. Taken together, geochemical and isotopic properties confirm that the carbonates were formed under oxic conditions triggered by the water‐rock interaction. For a reliable estimate of CO2 sequestered by carbonates of the Barzaman Formation, a systematic groundwater analysis is recommended to determine the contribution of CO2 in DIC.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 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) | 0.000 | 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 source (direct Gemma or distilled Codex), 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".