Bibliographic record
Abstract
Abstract Economic deposits associated with terrestrial impact structures range from world-class to relatively localized occurrences. The more significant deposits are introduced under the classification: progenetic, syngenetic or epigenetic, with respect to the impact event. However, there is increasing evidence that post-impact hydrothermal systems at large impact structures have remobilized some progenetic deposits, such as some of the Witwatersrand gold deposits at the Vredefort impact structure. Impact-related hydrothermal activity may also have had a significant role in the formation of ores at such syngenetic ‘magmatic’ deposits as the Cu-Ni-platinum-group elements ores associated with the Sudbury impact structure. Although Vredefort and Sudbury contain world-class mineral deposits, in economic terms hydrocarbon production dominates natural resource deposits found at impact structures. The total value of impact-related resources in North America is estimated at US$18 billion per year. Many impact structures remain to be discovered and, as targets for resource exploration, their relatively invariant, but scale-dependent properties, may provide an aid to exploration strategies.
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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 | 0.003 | 0.002 |
| Science and technology studies | 0.001 | 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) | 0.009 | 0.001 |
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".