Abstract—Mollusk migrations of various intensity in the Kimmeridgian to Valanginian time span were estab-
Bibliographic record
Abstract
lished in the Boreal Atlantic (West and East European Provinces), Boreal Pacific (Chukotka-Canadian and Boreal Pacific Provinces), and Arctic Realms of the Panboreal Superrealm. According to intensity degree, the migrations are classified as expansions, i.e., mass migrations, and influence migrations, i.e., penetration of sep-arate taxa. Migrations of the cross- and unidirectional types are distinguished according to directions of taxa exchange. Mollusks (ammonites, belemnites, and bivalves) are subdivided into Tethyan and Boreal forms, which inhabited areas south of 45°N, and north of 50°N, respectively. Low-boreal mollusks distinguished among the latter were characteristic of an ecotone between the Panboreal and Tethy s-Panthalassa Superrealms, and Boreal-Arctic taxa dwelt north of 60°N. The ecotone of the Boreal Atlantic Realm was situated between 50 ° and 55°N. The ecotone zone persistently existed in the Boreal Pacific Realm. The ammonite ecotone of the Chukotka-Canadian Province (Primor'e) was between 45 ° and 55°N. In the Boreal Pacific Province (northern California), an ecotone of the Tithonian-Valanginian time was located between 40 ° and 50°N. Water tempera-ture lower in the north was the major factor that influenced Boreal-Tethyan migrations and positioning of bio-geographic ecotones. The coincidence of transgression peaks with the ammonite migration events is character-istic only of the Kimmeridgian-Middle Volgian time, when northward migrations of the Tethyan ammonites coincided with sea level rises. The Berriasian expansion of berriasellids to the Central Russian Sea was not
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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) | 0.002 | 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".