Changes in Type II Kerogen Density as a Function of Maturity: Evidence from the Kimmeridge Clay Formation
Bibliographic record
Abstract
Kerogens were purified from 26 samples of the Kimmeridge Clay Formation over the full range of maturities pertinent to petroleum generation. Most samples comprised >90% amorphous organic matter (AOM). Prior to and during the early phase of petroleum generation, kerogen densities range between 1.18 and 1.25 g cm - 3 . During peak and late stage petroleum generation, densities increase to ∼1.35 g cm - 3 as hydrogen indices decrease from ∼350 to 50 mg HC/g C. The data are qualitatively consistent with the loss of alkyl carbon from kerogen to petroleum and the increased aromatization of remaining carbon. The density increase observed for AOM contrasts with the data for vitrinite, which exhibits a decrease in density at maturity levels relevant to petroleum generation. The contrasting behavior of AOM and vitrinite is thought to reflect the differing structural composition of the two kerogen types, most obviously the greater initial aromaticity of vitrinite.
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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 | 0.000 |
| 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".