Islands of proglacial lake Ojibway acted as outposts favoring postglacial forest migration in northwestern Québec
Bibliographic record
Abstract
At the beginning of the Holocene, the Laurentide Ice Sheet was progressively melting and liberating Canadian landscapes. Proglacial Lake Ojibway formed at the contact of the glacier and covered western Québec and eastern Ontario for approximately 2000 years before flushing into James Bay around 8,200 years ago. Lake Ojibway could have limited the afforestation of newly liberated landscapes but could have also provided migratory outposts on its islands. Indeed, several islands were present on Lake Ojibway which could have been colonized by forests before the drainage of lake Ojibway. We studied lake sediments from a small lake located on a paleo-island of Lake Ojibway in Aiguebelle National Park, in order to test the outpost hypothesis. Radiocarbon dating, XRF analysis and charcoal analysis reveal that organic matter (gyttja) started to accumulate around 9,626 years before today (i.e., 1400 years before Lake Ojibway retreat). The signatures of Ca, Sr and Si indicate that soil erosion declined between 9500 and 9000 years before present, meaning this paleo-island was probably colonized during this interval as vegetation stabilizes the soils. Moreover, K (an indicator of vegetation extension) also suggests that afforestation occurred around 9,250 years before present. Macroscopic charcoal particles reveal that one local fire likely occurred 9239 years before present. Burned conifer needle fragments were found among the fossil charcoals, lending support to the hypothesis of wildfire occurrence. All the studied indicators suggest paleo-island colonization around 9,250 years before present, more than 1,000 years before Lake Ojibway retreat.
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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 | 0.000 | 0.001 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| 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".