Late Carboniferous Tropical Dryland Vegetation in an Alluvial-plain Setting, Joggins, Nova Scotia, Canada
Bibliographic record
Abstract
Abstract The composition and ecology of Late Carboniferous tropical, dryland plant communities are described for the first time. The study focuses on a 700-m-thick succession through the Langsettian Joggins Formation. Red bed units (5–110 m thick) bearing isolated pedogenic carbonate nodules occur at fourteen intervals and are interpreted as originating in a seasonally dry, well-drained, alluvial-plain setting characterized, in places, by an anastomosing fluvial geometry. A quantitative quadrat analysis of red bed floral assemblages preserved as compressions, impressions, calcareous permineralizations, and charcoal was undertaken. Cordaites, represented by woody trunks, branches, pith casts, leaves, and seeds, comprise 74% of the red bed floral thanatomass, together with minor pteridosperms and sphenopsids, and rare sigillarian lycopsids. Taphonomic data demonstrate that while fire-prone cordaite-pteridosperm vegetation dominated nearly all seasonally dry floodplain niches, hydrophilic lycopsids and sphenopsids were restricted to riparian settings where water availability was greatest. Calculation of standard diversity indices indicates that growing conditions were generally stressful, consistent with a seasonal environment. The composition of these dryland communities differs markedly from lycopsid-dominated wetland communities known from gray, coal-bearing successions at other intervals in the Joggins Formation. Sequence stratigraphic analysis of the Joggins Formation suggests that dryland communities represent the vegetation of seasonal continental-interior environments in contrast to wetland communities that grew in humid coastal settings. Repeated alternations between continental and coastal settings were caused by tectonically and/or eustatically driven base-level fluctuations that resulted in marine transgressive-regressive rhythms minimally hundreds of kilometers long.
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 | 0.001 | 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".