Lower Devonian coaly shales of northern New Brunswick, Canada: plant accumulations in the early stages of Terrestrial colonization
Bibliographic record
Abstract
Abstract: We describe two Early Devonian occurrences of coaly shale composed mainly of the compacted remains of early plants, such that they resemble coal. Among the earliest thick phytodebris accumulations known, the occurrences lie within Pragian strata of the Val d'Amour Formation and Emsian strata of the Campbellton Formation of northern New Brunswick, and were deposited in low-energy wetlands where they were rapidly buried. Although the coaly shales did not yield recognizable plant taxa, numerous taxa are present in adjacent beds. Petrographic analysis revealed an average of 80.7% vitrinite (predominantly telovitrinite) and 18.7% liptinite (predominantly sporinite) on a mineral-matter-free basis, with a higher vitrinite content than most Devonian coals. Low sulfur content and atomic C/N ratios that vary from 44.3 to 82.1 in organic-rich samples indicate terrestrial derivation. Vitrinite reflectance in organic-rich samples (21.4–35.6 wt % total organic carbon) ranges from 0.48 to 1.00, indicating a low degree of thermal alteration that is supported by cross-polarization spectra from studies of 13C nuclear magnetic resonance; two carbon-poor samples were thermally altered to anthracitic rank adjacent to an intrusive body. Although plants at this time were still comparatively primitive, the presence at both sites of specimens with recognizable lignified cellular structures in vitrinite and particularly thick and resistant cuticle may represent an important step in peat development. In these Early Devonian formations, diverse assemblages of small vascular plants are present in a range of environments, and the plants were sufficiently abundant to form coal-like accumulations under suitable burial conditions, serving as a proxy for plant biomass and vegetation cover in the early stages of terrestrial colonization.
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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 | 0.002 | 0.002 |
| 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".