Latest Mid-Pennsylvanian tree-fern forests in retrograding coastal plain deposits, Sydney Mines Formation, Nova Scotia, Canada
Bibliographic record
Abstract
A latest Mid-Pennsylvanian (early Cantabrian) tree-fern forest is reported from Cape Breton Island, Nova Scotia. The fossil forest is rooted below the Point Aconi coal seam of the Sydney Mines Formation at Cranberry Head. The tree-ferns are preserved in the deposits of a coastal plain, subject to brackish incursions. They were constructed of psaronid-type trunks and massive pecopterid fronds, and locally intergrew with sigillarian lycopsids, neuropterid pteridosperms, and calamiteans. Basal stump diameter measurements, including the root mantle, range from 12 to 89 cm, indicating that the ferns were mostly large forest trees, rather than shrubs. Stump distribution measurements on palaeosols indicate that localized patches of tree-fern-dominated forest attained densities of c . 3850 trees per hectare when scaled up to standard forestry units, much denser than typical Mid-Pennsylvanian lycopsid forests. Tree-ferns dominantly grew in aggrading floodbasin settings, and a few of the largest trees show evidence for post-burial regeneration. Being approximately coeval with the late Mid-Pennsylvanian extinction event, which resulted in tree-fern forests rising to dominate tropical lowlands for the first time, the Cranberry Head fossil forests provide insight into community composition and structure during a critical phase of ecosystem reorganization.
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 | 0.000 |
| 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".