Thermal history of the Arctic Ocean environs adjacent to North America during the last 3.5 Ma and a possible mechanism for the cause of the cold events (major glaciations and permafrost events)
Bibliographic record
Abstract
At 3.5 Ma, the Arctic Ocean was unfrozen, and only during the second Pliocene cold event (Californian - 3.0 Ma) did an extensive glaciation occur in Alaska-Yukon and Iceland. The sea froze during the third (Alaskan - 2.58 Ma) event as the western Arctic cooled rapidly. Baffin Island and Labrador were the centres of ice sheets, and ice-rafted debris appeared in the North Atlantic. Shrub-tundra replaced boreal forest in the west during the next warm episode but forested-shrubtundra persisted in north Greenland during the next (Wyoming - 2.2 Ma) cold event. During the last Pliocene (Montanan - 1.9 Ma) cold event, tundra surrounded the Arctic basin with widespread permafrost in unglaciated areas. Quaternary cold events were more frequent, with tundra persisting on land during warm episodes, although coastal seas usually thawed seasonally. There was a continuous cooling trend due to the demise of the Tethyan sea, but the 18 O marine curve shows about 130 fluctuations compared with 14 major cold events on land. The cause of the terrestrial changes seems to be the interaction of many cyclical controls with different periodicities. When enough cycles are synchronized for air temperature to cross a critical threshold, a climatic change occurs. The critical thresholds are dependent on local environments and latitude.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
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 | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".