Early Cambrian maximum depositional age for the upper Yelverton Formation, northern Ellesmere Island, Nunavut
Bibliographic record
Abstract
U-Pb detrital zircon analysis of sandstone samples collected from northern Ellesmere Island during the summer of 2017 provides new depositional age constraints for the Yelverton Formation. Two samples from the same outcrop locality near the top of the formation have yielded an Early Cambrian maximum depositional age (MDA) of 532.1 ± 9.1 Ma. Because the overlying Grantland Formation contains late Early Cambrian trilobites (Oldhamia), we conclude that the uppermost Yelverton Formation is Early Cambrian. A near-depositional age fraction of detrital zircon is interpreted as a proxy for the age of igneous rocks within the Yelverton Formation, which is conservatively estimated as ranging from 551.1 ± 8.9 Ma to 532.1 ± 9.1 Ma.
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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 | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".