Under the volcano: A new dimension in Ar‐Ar dating of volcanic ash
Bibliographic record
Abstract
A significant part of the history of the Greek island of Kos has been decoded from a handful of volcanic ash by argon‐argon laser probe dating of single crystals of the minerals sanidine, plagioclase and quartz. On a 3‐D argon isotope plot, the data define six straight lines, corresponding to four distinct volcanic events from 161 to 1728 ka. All four events produced plagioclase crystals, whose ages and Ca/K ratios are consistent with the known evolution of the rest of the Aegean arc. Sanidine appeared only in the final eruption at 161 ka. The joint occurrence of quartz and plagioclase at a 925 ka event implies that quartz did not reside for millennia in the magma, as has been suggested for quartz from the Bishop Tuff, California. The step‐heated cooling age of a schist fragment from the ash provides the first radiometric evidence for ∼250 Ma crust under the volcano.
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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 | 0.002 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.002 | 0.003 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".