GEOGRAPHIC DIFFERENTIATION OF BOREAL AMMONOIDS IN THE LADINIAN AGE (<i>Middle Triassic</i>)
Bibliographic record
Abstract
Studying the spatial distribution of specific groups of marine invertebrates in the geological past and analyzing their geographic differentiation over time are crucial for understanding both their evolutionary patterns and the history of marine basin development. This study, based on modern paleontological and biostratigraphic data of the Boreal Triassic, refines the taxonomic composition and distribution of Ladinian ammonoids across various regions of the Boreal Realm. Zonal correlation on ammonoids of Ladinian deposits has been carried out for Northeast Asia, British Columbia, the Canadian Arctic Archipelago, northern Greenland, Svalbard, and Franz Josef Land, providing a chronological basis for comparative analysis of coeval ammonoid faunas. The qualitative and quantitative comparative analysis of ammonoid assemblages for different phases of the Ladinian Age has established that Northeast Asia consistently belonged to the Siberian Province of the Boreal Realm. The separation of the Canadian Province of the Boreal Realm occurred at the end of the constantis Phase due to the penetration of trachyceratids (genus Protrachyceras) into the paleobasins of the Canadian Arctic Archipelago. Subsequently, starting from the maclearni Phase, the area of the Canadian province expanded due to the migration of Tethyan forms into the paleobasins of Svalbard. The migrations of trachyceratids, gymnitids, and lobitids into boreal paleobasins from the Tethys Ocean, as well as the dispersal of Boreal tsvetkovitids and nathorstitids into ecotonal and Tethyan paleowaters of British Columbia, were influenced not only by circumpolar currents but likely, by the lifestyle of ammonoids and their adaptation to a broader or narrower range of marine basin depths.
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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 | 0.000 | 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".