Palynostratigraphy of the lower Paleogene Margaret Formation at Stenkul Fiord, Ellesmere Island, Nunavut, Canada
Bibliographic record
Abstract
The upper Paleocene to lower Eocene Margaret Formation exposed at Stenkul Fiord on southern Ellesmere Island, Nunavut, Canada, represents a nearly continuous terrestrial succession of microfossil-rich clastic sediments and coal. These strata were deposited at a time of extensive tectonic activity associated with Eurekan deformation. The precise chronology of the Eurekan deformation is poorly known. Prior studies at Stenkul Fiord provided a stratigraphic overview and relative age estimates for exposed strata but lack the absolute age control required to investigate the timing of deformation events. Strata at Stenkul Fiord preserve evidence of Arctic forests that may have grown during hyperthermal events that characterized the Paleogene, namely, the Paleocene-Eocene Thermal Maximum (PETM) and Eocene Thermal Maximum 2 (ETM2). A quantitative palynological approach is herein used to define a new higher-resolution biostratigraphic framework for the Margaret Formation strata at Stenkul Fiord. This resulting improved biostratigraphic framework is integrated with new absolute age control of 53.7 ± 0.06 Ma provided by U-Pb ID-TIMS of zircon preserved in an ash bed within the studied succession. Nine pollen zones are defined based on cluster analysis, NMDS ordination, first- and last occurrences of taxa, and angiosperm pollen taxa diversity (H′). The presence of thermophilic pollen taxa at Stenkul Fiord provides evidence of climates related to the globally warm climates during the early Paleogene.
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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 | 0.002 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| 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".