High-resolution isotope geochemistry of the gas-hydrate-free gas transition in the JAPEX/JNOC/GSC et al. Mallik 5L-38 gas hydrate production research well
Bibliographic record
Abstract
Drillcore from the gas hydrate-free gas transition zone in the Mallik 5L-38 gas hydrate production research well was subsampled at a 2 cm resolution and pore waters were vacuum extracted. Variations in major-ion geochemistry and ?18O values are retained at the 2 to 3 cm scale, with trends developing at scales greater than 20 cm. Above the transition, d18O (-14 ± 1.0%ø) and chloride (278 ± 97 mmol/L) values suggest a precursor pore water of roughly 50% seawater and low-d18O freshwater, and have an inverse correlation due to pore-water freshening during gas hydrate decomposition. Below the transition, excess chloride (622 ± 125 mmol/L) and low d18O (-11.4 ± 3.3%ø) values suggest downward diffusion of solutes following gas hydrate formation. The low d18Ofreshwater is glacial meltwater infiltrating along permeable sediment units during periods of glaciation and low sea level. Sulphate anomalies indicate the presence of readily oxidized sulphide minerals from sulphate reduction prior to gas hydrate growth.
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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 | 0.000 |
| 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) | 0.001 | 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".