Trace Element and Isotopic Analysis by Laser Ablation ICP-MS of Ore Deposit Bitumens: A Test Case with Uranium Ores from Oklo, Gabon
Bibliographic record
Abstract
Carbonaceous substances (CS) such as kerogen and derivative bitumens are closely linked to the origin of various types of ore deposits. Examples are metal accumulations in living organisms, black shales, crude oils, solid bitumens, and coals. Although presently a marginal economic proposition, the uranium ores of Oklo provide a classic case. At Oklo, solid bitumen occurs closely associated with the several main uranium ore types and also as discrete veinlets in the 2.1 Ga old country rock shales. These bitumen occurrences have been distinguished on the basis of field evidence, petrography, carbon isotopic signatures, and degree of thermal maturation. Chemical analysis by laser ablation inductively coupled plasma-mass spectrometry (ICP-MS) now allows detailed chemical characterization of CS such as these solid bitumens. For the first time, the technique has been used to produce quantitative in situ trace element and isotopic analysis of bitumen. There is a potential here to make major contributions to the understanding of Oklo and other ore deposits associated with carbonaceous substances.
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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 | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 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".