Chlorite diagenesis in reservoir sandstones of the Lower Missisauga formation, offshore Nova Scotia
Bibliographic record
Abstract
Diagenetic chlorite rims on quartz grains preserve porosity by preventing the formation of secondary, pore-filling quartz overgrowths in wells from the Venture and Thebaud fields. Elsewhere, in the Norwegian Sea and the US Gulf Coast, such chlorite rims have been interpreted as an early burial diagenetic feature related to the input of iron from rivers or volcanic activity, or to later diagenesis by basinal fluids. The purpose of this study is to evaluate which hypothesis is applicable to the Scotian Basin. \n \nA set of 45 sandstone samples from conventional cores were analyzed for mineralogy in thin section, mineral composition by electron microprobe, whole-rock chemistry, and X-ray diffraction. \n \nFrom analytical data, it can be argued that a precursor iron-rich clay has diagenetically altered to form chlorite rims during early burial diagenesis, before widespread precipitation of pore-filling kaolinite and quartz overgrowths. \n \nThe depositional environment, including the degree of bioturbation, may influence formation of early Fe-rich clay coatings. The quality of the final chlorite rim depends on the sea floor diagenetic environment, apparent from the correlation between the quality of chlorite rims and phosphorus. The conditions that favour precipitation of phosphate must also result in Fe-rich clay coatings and may also make some coatings a better precursor than others for the conversion to chlorite during burial diagenesis. The presence of other Fe-rich minerals may also indicate an abundant supply of iron in the early diagenetic environment.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| 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".