Geological evidence of a palynologically defined cooling in southeastern Canada at 10 000-8000 14C yr BP
Bibliographic record
Abstract
Post-glacial pollen spectra over a wide area of southeastern Canada have been interpreted as showing that the general warmth-adapted trend of regional vegetation change was interrupted between 10 000 and 8000 14C yr BP, reverting to conditions associated with a markedly cooler climate. This biotic reversal has been attributed to a climatic cooling caused by discharge of frigid water from glacial Lake Agassiz, through the Great Lakes to the Goldthwait Sea in the Gulf of St. Lawrence basin. Here, we assemble geological evidence from widely scattered localities in and around the Gulf of St. Lawrence, all previously reported, a majority unexplained, and ascribe it collectively to the same climatic cooling. We interpret the marine diamicts and other faunal reversals as the products of cooling, which intensified sea-ice conditions during the interval 10 000-8000 14C yr BP, specifically at 9300 14C yr (9170 yr, reservoir corrected), conditions resulting from that meltwater influx. This age was several centuries too young to be correlated with the Preboreal Oscillation, but several easterly overflows of Lake Agassiz occurred before and after this date, and may have increased sea-ice in the Goldthwait Sea, singly or by hysteresis. Other truly glacial features in southeastern Canada, such as moraine systems and diamictons, are also referred to this cooling.
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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 | 0.001 | 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) | 0.002 | 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".