Paleoecology and ice limits of the early Fraser glaciation (Marine Isotope Stage 2) on Haida Gwaii, British Columbia, Canada
Bibliographic record
Abstract
Abstract Our study combines new geological and paleoecological information to reconstruct the glacial history and terrestrial paleoenvironments on Haida Gwaii during the advance phase of the Fraser glaciation (Marine Isotope Stage 2). At Cape Ball on eastern Graham Island, five accelerator mass spectrometry radiocarbon ages ranging from 23,200±280 to 26,650±390 14 C yr BP (ca. 27,000–31,400 cal yr BP) record the earliest approach of mainland glaciers to Haida Gwaii. Abundant marine dinoflagellate cysts indicate isostatic depression by glacial ice in Hecate Strait to the east. At Mary Point on the north coast of Graham Island, similar outwash of a piedmont lobe advancing westward along Dixon Entrance preserves plant remains dated from 19,270±360 to 23,740±300 14 C yr BP (22,500–28,600 cal yr BP). These sediments also contain marine indicators. Plant macrofossils, pollen, and invertebrates support the geological evidence of a proglacial environment under a colder-than-present macroclimate. Although some trees were likely present on Graham Island at this time, tundra-like plant communities dominated low-lying areas. A large area that appears to have been ice-free during this time is a portion of the continental shelf off the east coast of Moresby Island, referred to provisionally as the “Hecate Refugium.”
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.003 |
| 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) | 0.003 | 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".