Role of zooclasts in the kerogen type and hydrocarbon potential of the lower Paleozoic Alum Shale
Bibliographic record
Abstract
This study investigates the role of zooclasts in the bulk organic matter composition, kerogen type, and hydrocarbon generation potential of the lower Paleozoic marine Alum shale in Baltoscandia, northwestern Europe. The results show that graptolite periderm is composed of non-granular cuticles and granular filling. The graptolite cuticle is non-fluorescing and has a well-polishing measurable surface, while the graptolite granular fraction is semi-translucent and has brownish fluorescence, suggesting remaining hydrocarbon generation potential. The graptolite granular fraction shows similar optical characteristics to fluorescing diagenetic solid bitumen. Both the graptolite granular fraction and diagenetic solid bitumen have low intensity yellow to brown fluorescence and contribute to generative potential (Rock-Eval S2). The sum of semi-quantitative zooclastic cuticle (non-granular graptolite cuticle, chitinozoan cuticle, and vitrinite-like) and diagenetic solid bitumen content, obtained from maceral point-counting, correlates with the non-generative organic carbon content. Enrichment of zooclastic cuticle in the samples is displayed as enrichment of inert organic carbon, and hence bulk geochemical kerogen of type III. This refractory carbon-rich maceral enrichment results represents autochthonous ‘refractory organic carbon dilution’ and will lead to Hydrocarbon Index (HI) underestimation. Confined hydrous pyrolysis was used to compare the hydrocarbon generation process of a zooclastic cuticle-lean sample (0.2 vol%) and a zooclastic cuticle-rich (1.6 vol%) sample. Results indicate that there are four stages of hydrocarbon generation in the artificial maturation of unconventional source rock of the Alum Shale. The zooclastic cuticle-lean sample has higher hydrocarbon generation potential and more oil-prone than the zooclastic cuticle-rich sample, which is gas-prone and generates more CO2. This difference in hydrocarbon generation is attributed to differences in the organic constituent composition.
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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 | 0.001 | 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".