The age of the Gunflint Formation, Ontario, Canada: single zircon UPb age determinations from reworked volcanic ash
Why this work is in the frame
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Bibliographic record
Abstract
The Gunflint Formation, a Paleoproterozoic chemicalclastic sedimentary assemblage outcropping to the immediate northwest of Lake Superior, became famous in 1954 as containing the oldest fossil assemblage known at that time. Older microfossils have since been discovered, but the Gunflint procaryotes remain one of the most diverse Precambrian fossil communities. The finding of possible multicellular organisms in correlative lithic units in Michigan has recently added to the need for an exact age of the Formation. Zircons were extracted from rainout and storm reworked volcanoclastic beds in the upper portion of the Gunflint Formation. A euhedral zircon population has yielded a 1878.3 ± 1.3 million years BP UPb age, believed to be nearly synchronous with the depositional age. This not only provides a precise age for the community of organisms, but also strongly supports a back-arc extensional setting for the Animikie Basin, rather than a foreland trough.
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Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.006 | 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 it