Taxonomy of Cretaceous–Paleogene coniferous woods and their distribution in fossil Lagerstätten of the high latitudes
Bibliographic record
Abstract
ABSTRACT Anatomical analyses of fossil woods, supplemented by information from coal petrographic investigations, provide data for reconstructing the Cretaceous–Paleogene, mostly swampy woodland vegetation of the high latitudes. This paper is focused on the taxonomic description of conifers that have been recovered from a number of plant fossil Lagerstätten in Nathorstland, Yukon North Slope–western Mackenzie Delta, Ellesmere Island, northern Trolleland, and Kotel’nyi Island. The investigation revealed a relatively low taxonomic diversity. Wood-anatomical identification of Taxodioxylon vanderburghii provides evidence for the genus Metasequoia. The determination of Glyptostroboxylon cf. rudolphii demonstrates the most likely presence of Glyptostrobus, and the genus Cunninghamia is proved by the identification of Glyptostroboxylon tenerum. Moreover, this first evidence of Cunninghamia in the high latitudes establishes this plant as an “Arctic conifer.” Piceoxylon laricinoides (Høeg) comb. nov., a new combination, is proposed for a fossil wood species that represents the genus Larix. Fossils identified as Protopiceoxylon woods, Protopiceoxylon sp., and Protopiceoxylon yukonense represent the extinct gymnospermous Protopinaceae group. A fossil forest from the Split Lake Lagerstätte focusing on the habitus of in situ trunks and stumps was reconstructed. The vegetation encompasses a succession with three stages, an Equisetum reed facies, a Metasequoia swamp forest facies, and a Larix swamp forest facies. The taxonomic investigation suggests a widely distributed zone of vegetation with various conifers in the high latitudes. The lignite samples are characterized by predominantly woody (xylite) tissues with well-preserved, mummified stems and roots and a variable content of liptinite macerals, mostly resinite and suberinite. The intensive yellow fluorescent textinite of characteristic zoned structures and distinct microspores was observed in all investigated lignites.
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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 | 0.000 | 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) | 0.001 | 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".