Lead isotope ratios in 16th century copperware traded to North America: the Swedish connection
Bibliographic record
Abstract
Isotope analyses have been made on the trace amounts of lead in a small set of late 16th century pure copper trade kettles and kettle debris from Indigenous sites in eastern Canada. The isotope ratios are highly correlated. We interpret these correlations as the mixing of copper from Precambrian Swedish ores with metal from one or more of the Palaeozoic deposits occurring in central Europe and the British Isles. The data enable us to identify samples of pure Swedish copper, metal consisting of mixtures of Swedish and central European – British copper, and with less certainty, samples derived entirely from the latter deposits. Although most of the trace element concentrations in the coppers are quite variable, it appears that nickel values may be less so (∼100 ppm in pure Swedish samples, and ∼1100 ppm in the central European – British sources). Based on these values, two-component mixing relations provide estimates of the fractions of Swedish end members in mixed samples. These results suggest that more than half of the copper used in forming the kettles originated in Sweden.
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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 | 0.006 | 0.005 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.002 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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".