Age, stable isotopes, and redescription of the first mammoth tooth from the Labrador Peninsula
Bibliographic record
Abstract
A mammoth ( Mammuthus) molar was discovered on Long Island, Nunavut in 1878, making it the first mammoth fossil from the Labrador Peninsula and most northeastern mammoth in eastern North America. On the basis of morphology, we cautiously identify the tooth as the worn stump of the third left upper molar of a woolly mammoth ( Mammuthus primigenius) although it was originally identified as the premolar of a Columbian mammoth ( Mammuthus columbi). The Long Island tooth yielded an infinite calibrated radiocarbon age of >39 800 years. However, bulk-sampled stable oxygen isotopes in the tooth’s enamel structural carbonate suggest a local climate with a mean air temperature of around 2.1 °C. This roughly corresponds to the predicted temperatures in the Long Island area during climatic optima. The tooth’s age can further be constrained by the presence of glaciers in the Long Island area and the appearance of M. primigenius-type mammoths in North America. Thus, we estimate the Long Island tooth to be between 500 and 55 ka old, but more likely from an interglacial period, and most likely from MIS5e. The Long Island tooth has a collagen δ 15 N value of 10.7‰, higher than expected for comparable North American mammoths and possibly indicative of nutritional stress. The tooth’s collagen δ 13 C value of −21.6‰ falls within the range of values for comparable mammoths, and the calculated dietary δ 13 C value of −26.0‰ suggests a diet rich in C3 plants.
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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 | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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".