A window into mid-latitudinal Early Eocene environmental variability: a high-resolution palynological analysis of the Falkland site, Okanagan Highlands, British Columbia, Canada
Bibliographic record
Abstract
A series of Eocene lake shale deposits from British Columbia, coined the Okanagan Highlands, are dated from associated volcanic ash as mostly from the Early Eocene Climatic Optimum (EECO), the longest persisting of the early Paleogene hyperthermals. In this report we focus on high-resolution palynological sampling of short sequences for the Falkland site to determine if they record centennial- or millennial-scale vegetation change during the EECO. The Falkland shales consist of alternating dark- and light-coloured irregular laminae, along with interleaved tephras from volcanic eruptions. At this site it is apparent that deposition occurred over several millennia. Pollen grains were counted under light microscopy using a standard transect method, with clustering analysis determining whether the data show any long-term trends in plant representation and abundance. Our data show that regional vegetation was impacted by millennial- to centennial-scale climatic variability, as well as the effects of volcanic eruptions. At Falkland there appears to be alterations in vegetation assemblages (birch – golden larch association to fir–spruce) that reflect longer-term (centennial to millennial) climatic transitions (warm/wet to cool/dry). Within this sequence, a period of environmental disturbance (reflected in the presence of multiple volcanic ash layers, wave ripple marks, and a fish-kill layer) has a marked impact on vegetation representation, with a dramatic increase in Abies and Picea pollen at the expense of Alnus and Betula, which do eventually recover. These results suggest mid-latitude millennial-scale climate oscillations in the waning period of the EECO of a similar magnitude to Holocene variability.
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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 | 0.004 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.002 | 0.000 |
| Open science | 0.001 | 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".